* bug#37440: [PATCH] New rx implementation with extension constructs
@ 2019-09-17 12:49 Mattias Engdegård
2019-09-17 17:47 ` Paul Eggert
0 siblings, 1 reply; 5+ messages in thread
From: Mattias Engdegård @ 2019-09-17 12:49 UTC (permalink / raw)
To: 37440
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[Continuing from https://lists.gnu.org/archive/html/emacs-devel/2019-09/msg00048.html]
Here is a new rx implementation (faster, easier to work with, fewer bugs, better tests), and, as a separate patch, an rx extension mechanism adding the macros `rx-define', `rx-let' and `rx-let-eval'.
The first patch is a ground-up rewrite of rx. It should be completely compatible.
The second patch adds
(rx-define NAME [ARGS] RX)
(rx-let ((NAME [ARGS] RX) ...) BODY)
(rx-let-eval ((NAME [ARGS] RX) ...) BODY)
as mentioned in the emacs-devel thread earlier. Additions to the manual are included.
Although I believe this to be a consistent and useful design that could be used as-is, some points worth thinking about are:
* Allow for multiple RXs in the definitions, making an implicit (seq ...). This could be done with the Schemeish syntax
(rx-define NAME RX...)
(rx-define (NAME ARGS...) RX...)
which is quite readable as "definition mirrors use". Should then the &rest parameter be declared using a dotted list, as
(rx-define (NAME ARG1 ARG2 . ARG-REST) RX...)
?
* There is some disagreement regarding whether function-like definitions should be standard Lisp expressions instead of the restricted substitution-based macros in this patch, as in
(rx-define whole (x) `(seq bos ,x eos))
I believe the usability of the chosen design is better, but see the point of not reinventing the wheel.
* Not entirely satisfied with the name `rx-let-eval', but unless someone comes up with something better, it stands.
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From c467191f89de80c4ea1478bd7a137edaa5883a6b Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Mattias=20Engdeg=C3=A5rd?= <mattiase@acm.org>
Date: Sun, 15 Sep 2019 16:11:09 +0200
Subject: [PATCH 1/2] New rx implementation
* lisp/emacs-lisp/rx.el:
* test/lisp/emacs-lisp/rx-tests.el:
* doc/lispref/searching.texi (Rx Constructs):
Rewrite rx for correctness, clarity, and performance. The new
implementation retains full compatibility and has more comprehensive
tests.
* lisp/emacs-lisp/re-builder.el (reb-rx-font-lock-keywords):
Adapt to changes in internal variables in rx.el.
---
doc/lispref/searching.texi | 4 +-
lisp/emacs-lisp/re-builder.el | 9 +-
lisp/emacs-lisp/rx.el | 1822 ++++++++++++++----------------
test/lisp/emacs-lisp/rx-tests.el | 331 ++++--
4 files changed, 1099 insertions(+), 1067 deletions(-)
diff --git a/doc/lispref/searching.texi b/doc/lispref/searching.texi
index 1286b63446..21b1f7b68b 100644
--- a/doc/lispref/searching.texi
+++ b/doc/lispref/searching.texi
@@ -1044,11 +1044,9 @@ Rx Constructs
The various forms in @code{rx} regexps are described below. The
shorthand @var{rx} represents any @code{rx} form, and @var{rx}@dots{}
-means one or more @code{rx} forms. Where the corresponding string
+means zero or more @code{rx} forms. Where the corresponding string
regexp syntax is given, @var{A}, @var{B}, @dots{} are string regexp
subexpressions.
-@c With the new implementation of rx, this can be changed from
-@c 'one or more' to 'zero or more'.
@subsubheading Literals
diff --git a/lisp/emacs-lisp/re-builder.el b/lisp/emacs-lisp/re-builder.el
index 961d26a721..1054f1453b 100644
--- a/lisp/emacs-lisp/re-builder.el
+++ b/lisp/emacs-lisp/re-builder.el
@@ -816,13 +816,12 @@ reb-mark-non-matching-parenthesis
(require 'rx)
(defconst reb-rx-font-lock-keywords
- (let ((constituents (mapcar (lambda (rec)
- (symbol-name (car rec)))
- rx-constituents))
- (syntax (mapcar (lambda (rec) (symbol-name (car rec))) rx-syntax))
+ (let ((constituents (mapcar #'symbol-name rx--builtin-forms))
+ (syntax (mapcar (lambda (rec) (symbol-name (car rec)))
+ rx--syntax-codes))
(categories (mapcar (lambda (rec)
(symbol-name (car rec)))
- rx-categories)))
+ rx--categories)))
`(
(,(concat "(" (regexp-opt (list "rx-to-string") t) "[[:space:]]")
(1 font-lock-function-name-face))
diff --git a/lisp/emacs-lisp/rx.el b/lisp/emacs-lisp/rx.el
index 249529e54e..8ab32bdb1d 100644
--- a/lisp/emacs-lisp/rx.el
+++ b/lisp/emacs-lisp/rx.el
@@ -1,11 +1,7 @@
-;;; rx.el --- sexp notation for regular expressions -*- lexical-binding: t -*-
+;;; rx.el --- S-exp notation for regexps --*- lexical-binding: t -*-
;; Copyright (C) 2001-2019 Free Software Foundation, Inc.
-;; Author: Gerd Moellmann <gerd@gnu.org>
-;; Maintainer: emacs-devel@gnu.org
-;; Keywords: strings, regexps, extensions
-
;; This file is part of GNU Emacs.
;; GNU Emacs is free software: you can redistribute it and/or modify
@@ -23,937 +19,837 @@
;;; Commentary:
-;; This is another implementation of sexp-form regular expressions.
-;; It was unfortunately written without being aware of the Sregex
-;; package coming with Emacs, but as things stand, Rx completely
-;; covers all regexp features, which Sregex doesn't, doesn't suffer
-;; from the bugs mentioned in the commentary section of Sregex, and
-;; uses a nicer syntax (IMHO, of course :-).
-
-;; This significantly extended version of the original, is almost
-;; compatible with Sregex. The only incompatibility I (fx) know of is
-;; that the `repeat' form can't have multiple regexp args.
-
-;; Now alternative forms are provided for a degree of compatibility
-;; with Olin Shivers' attempted definitive SRE notation. SRE forms
-;; not catered for include: dsm, uncase, w/case, w/nocase, ,@<exp>,
-;; ,<exp>, (word ...), word+, posix-string, and character class forms.
-;; Some forms are inconsistent with SRE, either for historical reasons
-;; or because of the implementation -- simple translation into Emacs
-;; regexp strings. These include: any, word. Also, case-sensitivity
-;; and greediness are controlled by variables external to the regexp,
-;; and you need to feed the forms to the `posix-' functions to get
-;; SRE's POSIX semantics. There are probably more difficulties.
-
-;; Rx translates a sexp notation for regular expressions into the
-;; usual string notation. The translation can be done at compile-time
-;; by using the `rx' macro. The `regexp' and `literal' forms accept
-;; non-constant expressions, in which case `rx' will translate to a
-;; `concat' expression. Translation can be done fully at run time by
-;; calling function `rx-to-string'. See the documentation of `rx' for
-;; a complete description of the sexp notation.
-;;
-;; Some examples of string regexps and their sexp counterparts:
-;;
-;; "^[a-z]*"
-;; (rx line-start (0+ (in "a-z")))
-;;
-;; "\n[^ \t]"
-;; (rx ?\n (not (in " \t")))
-;;
-;; "\\*\\*\\* EOOH \\*\\*\\*\n"
-;; (rx "*** EOOH ***\n")
-;;
-;; "\\<\\(catch\\|finally\\)\\>[^_]"
-;; (rx word-start (submatch (or "catch" "finally")) word-end
-;; (not (in ?_)))
-;;
-;; "[ \t\n]*:\\($\\|[^:]+\\)"
-;; (rx (* (in " \t\n")) ":"
-;; (submatch (or line-end (+ (not (in ?:))))))
-;;
-;; "^content-transfer-encoding:\\(?:\n?[\t ]\\)*quoted-printable\\(?:\n?[\t ]\\)*"
-;; (rx line-start
-;; "content-transfer-encoding:"
-;; (* (? ?\n) (in " \t"))
-;; "quoted-printable"
-;; (* (? ?\n) (in " \t")))
-;;
-;; (concat "^\\(?:" something-else "\\)")
-;; (rx line-start (regexp something-else))
-;;
-;; (regexp-opt '(STRING1 STRING2 ...))
-;; (rx (or STRING1 STRING2 ...)), or in other words, `or' automatically
-;; calls `regexp-opt' as needed.
-;;
-;; "^;;\\s-*\n\\|^\n"
-;; (rx (or (seq line-start ";;" (0+ space) ?\n)
-;; (seq line-start ?\n)))
+;; This facility allows writing regexps in a sexp-based language
+;; instead of strings. Regexps in the `rx' notation are easier to
+;; read, write and maintain; they can be indented and commented in a
+;; natural way, and are easily composed by program code.
+;; The translation to string regexp is done by a macro and does not
+;; incur any extra processing during run time. Example:
;;
-;; "\\$[I]d: [^ ]+ \\([^ ]+\\) "
-;; (rx "$Id: "
-;; (1+ (not (in " ")))
-;; " "
-;; (submatch (1+ (not (in " "))))
-;; " ")
+;; (rx bos (or (not (any "^"))
+;; (seq "^" (or " *" "["))))
;;
-;; "\\\\\\\\\\[\\w+"
-;; (rx "\\\\[" (1+ word))
-;;
-;; etc.
-
-;;; History:
+;; => "\\`\\(?:[^^]\\|\\^\\(?: \\*\\|\\[\\)\\)"
;;
+;; The notation is much influenced by and retains some compatibility with
+;; Olin Shivers's SRE, with concessions to Emacs regexp peculiarities,
+;; and the older Emacs package Sregex.
;;; Code:
-(require 'cl-lib)
-(require 'cl-extra)
-
-;; FIXME: support macros.
-
-(defvar rx-constituents ;Not `const' because some modes extend it.
- '((and . (rx-and 0 nil))
- (seq . and) ; SRE
- (: . and) ; SRE
- (sequence . and) ; sregex
- (or . (rx-or 0 nil))
- (| . or) ; SRE
- (not-newline . ".")
- (nonl . not-newline) ; SRE
- (anything . (rx-anything 0 nil))
- (any . (rx-any 1 nil rx-check-any)) ; inconsistent with SRE
- (any . ".") ; sregex
- (in . any)
- (char . any) ; sregex
- (not-char . (rx-not-char 1 nil rx-check-any)) ; sregex
- (not . (rx-not 1 1 rx-check-not))
- (repeat . (rx-repeat 2 nil))
- (= . (rx-= 2 nil)) ; SRE
- (>= . (rx->= 2 nil)) ; SRE
- (** . (rx-** 2 nil)) ; SRE
- (submatch . (rx-submatch 1 nil)) ; SRE
- (group . submatch) ; sregex
- (submatch-n . (rx-submatch-n 2 nil))
- (group-n . submatch-n)
- (zero-or-more . (rx-kleene 1 nil))
- (one-or-more . (rx-kleene 1 nil))
- (zero-or-one . (rx-kleene 1 nil))
- (\? . zero-or-one) ; SRE
- (\?? . zero-or-one)
- (* . zero-or-more) ; SRE
- (*? . zero-or-more)
- (0+ . zero-or-more)
- (+ . one-or-more) ; SRE
- (+? . one-or-more)
- (1+ . one-or-more)
- (optional . zero-or-one)
- (opt . zero-or-one) ; sregex
- (minimal-match . (rx-greedy 1 1))
- (maximal-match . (rx-greedy 1 1))
- (backref . (rx-backref 1 1 rx-check-backref))
- (line-start . "^")
- (bol . line-start) ; SRE
- (line-end . "$")
- (eol . line-end) ; SRE
- (string-start . "\\`")
- (bos . string-start) ; SRE
- (bot . string-start) ; sregex
- (string-end . "\\'")
- (eos . string-end) ; SRE
- (eot . string-end) ; sregex
- (buffer-start . "\\`")
- (buffer-end . "\\'")
- (point . "\\=")
- (word-start . "\\<")
- (bow . word-start) ; SRE
- (word-end . "\\>")
- (eow . word-end) ; SRE
- (word-boundary . "\\b")
- (not-word-boundary . "\\B") ; sregex
- (symbol-start . "\\_<")
- (symbol-end . "\\_>")
- (syntax . (rx-syntax 1 1))
- (not-syntax . (rx-not-syntax 1 1)) ; sregex
- (category . (rx-category 1 1 rx-check-category))
- (eval . (rx-eval 1 1))
- (literal . (rx-literal 1 1 stringp))
- (regexp . (rx-regexp 1 1 stringp))
- (regex . regexp) ; sregex
- (digit . "[[:digit:]]")
- (numeric . digit) ; SRE
- (num . digit) ; SRE
- (control . "[[:cntrl:]]") ; SRE
- (cntrl . control) ; SRE
- (hex-digit . "[[:xdigit:]]") ; SRE
- (hex . hex-digit) ; SRE
- (xdigit . hex-digit) ; SRE
- (blank . "[[:blank:]]") ; SRE
- (graphic . "[[:graph:]]") ; SRE
- (graph . graphic) ; SRE
- (printing . "[[:print:]]") ; SRE
- (print . printing) ; SRE
- (alphanumeric . "[[:alnum:]]") ; SRE
- (alnum . alphanumeric) ; SRE
- (letter . "[[:alpha:]]")
- (alphabetic . letter) ; SRE
- (alpha . letter) ; SRE
- (ascii . "[[:ascii:]]") ; SRE
- (nonascii . "[[:nonascii:]]")
- (lower . "[[:lower:]]") ; SRE
- (lower-case . lower) ; SRE
- (punctuation . "[[:punct:]]") ; SRE
- (punct . punctuation) ; SRE
- (space . "[[:space:]]") ; SRE
- (whitespace . space) ; SRE
- (white . space) ; SRE
- (upper . "[[:upper:]]") ; SRE
- (upper-case . upper) ; SRE
- (word . "[[:word:]]") ; inconsistent with SRE
- (wordchar . word) ; sregex
- (not-wordchar . "\\W"))
- "Alist of sexp form regexp constituents.
-Each element of the alist has the form (SYMBOL . DEFN).
-SYMBOL is a valid constituent of sexp regular expressions.
-If DEFN is a string, SYMBOL is translated into DEFN.
-If DEFN is a symbol, use the definition of DEFN, recursively.
-Otherwise, DEFN must be a list (FUNCTION MIN-ARGS MAX-ARGS PREDICATE).
-FUNCTION is used to produce code for SYMBOL. MIN-ARGS and MAX-ARGS
-are the minimum and maximum number of arguments the function-form
-sexp constituent SYMBOL may have in sexp regular expressions.
-MAX-ARGS nil means no limit. PREDICATE, if specified, means that
-all arguments must satisfy PREDICATE.")
-
-
-(defconst rx-syntax
- '((whitespace . ?-)
- (punctuation . ?.)
- (word . ?w)
- (symbol . ?_)
- (open-parenthesis . ?\()
- (close-parenthesis . ?\))
- (expression-prefix . ?\')
- (string-quote . ?\")
- (paired-delimiter . ?$)
- (escape . ?\\)
- (character-quote . ?/)
- (comment-start . ?<)
- (comment-end . ?>)
- (string-delimiter . ?|)
- (comment-delimiter . ?!))
- "Alist mapping Rx syntax symbols to syntax characters.
-Each entry has the form (SYMBOL . CHAR), where SYMBOL is a valid
-symbol in `(syntax SYMBOL)', and CHAR is the syntax character
-corresponding to SYMBOL, as it would be used with \\s or \\S in
-regular expressions.")
-
-
-(defconst rx-categories
- '((space-for-indent . ?\s)
- (base . ?.)
- (consonant . ?0)
- (base-vowel . ?1)
- (upper-diacritical-mark . ?2)
- (lower-diacritical-mark . ?3)
- (tone-mark . ?4)
- (symbol . ?5)
- (digit . ?6)
- (vowel-modifying-diacritical-mark . ?7)
- (vowel-sign . ?8)
- (semivowel-lower . ?9)
- (not-at-end-of-line . ?<)
- (not-at-beginning-of-line . ?>)
- (alpha-numeric-two-byte . ?A)
- (chinese-two-byte . ?C)
- (chinse-two-byte . ?C) ;; A typo in Emacs 21.1-24.3.
- (greek-two-byte . ?G)
- (japanese-hiragana-two-byte . ?H)
- (indian-two-byte . ?I)
- (japanese-katakana-two-byte . ?K)
- (strong-left-to-right . ?L)
- (korean-hangul-two-byte . ?N)
- (strong-right-to-left . ?R)
- (cyrillic-two-byte . ?Y)
- (combining-diacritic . ?^)
- (ascii . ?a)
- (arabic . ?b)
- (chinese . ?c)
- (ethiopic . ?e)
- (greek . ?g)
- (korean . ?h)
- (indian . ?i)
- (japanese . ?j)
- (japanese-katakana . ?k)
- (latin . ?l)
- (lao . ?o)
- (tibetan . ?q)
- (japanese-roman . ?r)
- (thai . ?t)
- (vietnamese . ?v)
- (hebrew . ?w)
- (cyrillic . ?y)
- (can-break . ?|))
- "Alist mapping symbols to category characters.
-Each entry has the form (SYMBOL . CHAR), where SYMBOL is a valid
-symbol in `(category SYMBOL)', and CHAR is the category character
-corresponding to SYMBOL, as it would be used with `\\c' or `\\C' in
-regular expression strings.")
-
-
-(defvar rx-greedy-flag t
- "Non-nil means produce greedy regular expressions for `zero-or-one',
-`zero-or-more', and `one-or-more'. Dynamically bound.")
-
-(defvar rx--compile-to-lisp nil
- "Nil means return a regexp as a string.
-Non-nil means we may return a lisp form which produces a
-string (used for `rx' macro).")
-
-(defun rx-info (op head)
- "Return parsing/code generation info for OP.
-If OP is the space character ASCII 32, return info for the symbol `?'.
-If OP is the character `?', return info for the symbol `??'.
-See also `rx-constituents'.
-If HEAD is non-nil, then OP is the head of a sexp, otherwise it's
-a standalone symbol."
- (cond ((eq op ? ) (setq op '\?))
- ((eq op ??) (setq op '\??)))
- (let (old-op)
- (while (and (not (null op)) (symbolp op))
- (setq old-op op)
- (setq op (cdr (assq op rx-constituents)))
- (when (if head (stringp op) (consp op))
- ;; We found something but of the wrong kind. Let's look for an
- ;; alternate definition for the other case.
- (let ((new-op
- (cdr (assq old-op (cdr (memq (assq old-op rx-constituents)
- rx-constituents))))))
- (if (and new-op (not (if head (stringp new-op) (consp new-op))))
- (setq op new-op))))))
- op)
-
-
-(defun rx-check (form)
- "Check FORM according to its car's parsing info."
- (unless (listp form)
- (error "rx `%s' needs argument(s)" form))
- (let* ((rx (rx-info (car form) 'head))
- (nargs (1- (length form)))
- (min-args (nth 1 rx))
- (max-args (nth 2 rx))
- (type-pred (nth 3 rx)))
- (when (and (not (null min-args))
- (< nargs min-args))
- (error "rx form `%s' requires at least %d args"
- (car form) min-args))
- (when (and (not (null max-args))
- (> nargs max-args))
- (error "rx form `%s' accepts at most %d args"
- (car form) max-args))
- (when type-pred
- (dolist (sub-form (cdr form))
- (unless (funcall type-pred sub-form)
- (error "rx form `%s' requires args satisfying `%s'"
- (car form) type-pred))))))
-
-
-(defun rx-group-if (regexp group)
- "Put shy groups around REGEXP if seemingly necessary when GROUP
-is non-nil."
+;; The `rx--translate...' functions below return (REGEXP . PRECEDENCE),
+;; where REGEXP is a list of string expressions that will be
+;; concatenated into a regexp, and PRECEDENCE is one of
+;;
+;; t -- can be used as argument to postfix operators (eg. "a")
+;; seq -- can be concatenated in sequence with other seq or higher (eg. "ab")
+;; lseq -- can be concatenated to the left of rseq or higher (eg. "^a")
+;; rseq -- can be concatenated to the right of lseq or higher (eg. "a$")
+;; nil -- can only be used in alternatives (eg. "a\\|b")
+;;
+;; They form a lattice:
+;;
+;; t highest precedence
+;; |
+;; seq
+;; / \
+;; lseq rseq
+;; \ /
+;; nil lowest precedence
+
+
+(defconst rx--char-classes
+ '((digit . digit)
+ (numeric . digit)
+ (num . digit)
+ (control . cntrl)
+ (cntrl . cntrl)
+ (hex-digit . xdigit)
+ (hex . xdigit)
+ (xdigit . xdigit)
+ (blank . blank)
+ (graphic . graph)
+ (graph . graph)
+ (printing . print)
+ (print . print)
+ (alphanumeric . alnum)
+ (alnum . alnum)
+ (letter . alpha)
+ (alphabetic . alpha)
+ (alpha . alpha)
+ (ascii . ascii)
+ (nonascii . nonascii)
+ (lower . lower)
+ (lower-case . lower)
+ (punctuation . punct)
+ (punct . punct)
+ (space . space)
+ (whitespace . space)
+ (white . space)
+ (upper . upper)
+ (upper-case . upper)
+ (word . word)
+ (wordchar . word)
+ (unibyte . unibyte)
+ (multibyte . multibyte))
+ "Alist mapping rx symbols to character classes.
+Most of the names are from SRE.")
+
+(defvar rx-constituents nil
+ "Alist of old-style rx extensions, for compatibility.
+
+Each element is (SYMBOL . DEF).
+
+If DEF is a symbol, then SYMBOL is an alias of DEF.
+
+If DEF is a string, then SYMBOL is a plain rx symbol defined as the
+ regexp string DEF.
+
+If DEF is a list on the form (FUN MIN-ARGS MAX-ARGS PRED), then
+ SYMBOL is an rx form with at least MIN-ARGS and at most
+ MAX-ARGS arguments. If MAX-ARGS is nil, then there is no upper limit.
+ FUN is a function taking the entire rx form as single argument
+ and returning the translated regexp string.
+ If PRED is non-nil, it is a predicate that all actual arguments must
+ satisfy.")
+
+;; TODO: Additions to consider:
+;; - A better name for `anything', like `any-char' or `anychar'.
+;; - A name for (or), maybe `unmatchable'.
+;; - A construct like `or' but without the match order guarantee,
+;; maybe `unordered-or'. Useful for composition or generation of
+;; alternatives; permits more effective use of regexp-opt.
+
+(defun rx--translate-symbol (sym)
+ "Translate an rx symbol. Return (REGEXP . PRECEDENCE)."
+ (pcase sym
+ ;; Use `list' instead of a quoted list to wrap the strings here,
+ ;; since the return value may be mutated.
+ ((or 'nonl 'not-newline 'any) (cons (list ".") t))
+ ('anything (rx--translate-form '(or nonl "\n")))
+ ((or 'bol 'line-start) (cons (list "^") 'lseq))
+ ((or 'eol 'line-end) (cons (list "$") 'rseq))
+ ((or 'bos 'string-start 'bot 'buffer-start) (cons (list "\\`") t))
+ ((or 'eos 'string-end 'eot 'buffer-end) (cons (list "\\'") t))
+ ('point (cons (list "\\=") t))
+ ((or 'bow 'word-start) (cons (list "\\<") t))
+ ((or 'eow 'word-end) (cons (list "\\>") t))
+ ('word-boundary (cons (list "\\b") t))
+ ('not-word-boundary (cons (list "\\B") t))
+ ('symbol-start (cons (list "\\_<") t))
+ ('symbol-end (cons (list "\\_>") t))
+ ('not-wordchar (cons (list "\\W") t))
+ (_
+ (cond
+ ((let ((class (cdr (assq sym rx--char-classes))))
+ (and class (cons (list (concat "[[:" (symbol-name class) ":]]")) t))))
+
+ ;; For compatibility with old rx.
+ ((let ((entry (assq sym rx-constituents)))
+ (and (progn
+ (while (and entry (not (stringp (cdr entry))))
+ (setq entry
+ (if (symbolp (cdr entry))
+ ;; Alias for another entry.
+ (assq (cdr entry) rx-constituents)
+ ;; Wrong type, try further down the list.
+ (assq (car entry)
+ (cdr (memq entry rx-constituents))))))
+ entry)
+ (cons (list (cdr entry)) nil))))
+ (t (error "Unknown rx symbol `%s'" sym))))))
+
+(defun rx--enclose (left-str rexp right-str)
+ "Bracket REXP by LEFT-STR and RIGHT-STR."
+ (append (list left-str) rexp (list right-str)))
+
+(defun rx--bracket (rexp)
+ (rx--enclose "\\(?:" rexp "\\)"))
+
+(defun rx--sequence (left right)
+ "Return the sequence (concatenation) of two translated items,
+each on the form (REGEXP . PRECEDENCE), returning (REGEXP . PRECEDENCE)."
+ ;; Concatenation rules:
+ ;; seq ++ seq -> seq
+ ;; lseq ++ seq -> lseq
+ ;; seq ++ rseq -> rseq
+ ;; lseq ++ rseq -> nil
+ (cond ((not (car left)) right)
+ ((not (car right)) left)
+ (t
+ (let ((l (if (memq (cdr left) '(nil rseq))
+ (cons (rx--bracket (car left)) t)
+ left))
+ (r (if (memq (cdr right) '(nil lseq))
+ (cons (rx--bracket (car right)) t)
+ right)))
+ (cons (append (car l) (car r))
+ (if (eq (cdr l) 'lseq)
+ (if (eq (cdr r) 'rseq)
+ nil ; lseq ++ rseq
+ 'lseq) ; lseq ++ seq
+ (if (eq (cdr r) 'rseq)
+ 'rseq ; seq ++ rseq
+ 'seq))))))) ; seq ++ seq
+
+(defun rx--translate-seq (body)
+ "Translate a sequence of one or more rx items. Return (REGEXP . PRECEDENCE)."
+ (if body
+ (let* ((items (mapcar #'rx--translate body))
+ (result (car items)))
+ (dolist (item (cdr items))
+ (setq result (rx--sequence result item)))
+ result)
+ (cons nil 'seq)))
+
+(defun rx--empty ()
+ "Regexp that never matches anything."
+ (cons (list regexp-unmatchable) 'seq))
+
+;; `cl-every' replacement to avoid bootstrapping problems.
+(defun rx--every (pred list)
+ "Whether PRED is true for every element of LIST."
+ (while (and list (funcall pred (car list)))
+ (setq list (cdr list)))
+ (null list))
+
+(defun rx--translate-or (body)
+ "Translate an or-pattern of one of more rx items.
+Return (REGEXP . PRECEDENCE)."
+ ;; FIXME: Possible improvements:
+ ;;
+ ;; - Turn single characters to strings: (or ?a ?b) -> (or "a" "b"),
+ ;; so that they can be candidates for regexp-opt.
+ ;;
+ ;; - Translate compile-time strings (`eval' forms), again for regexp-opt.
+ ;;
+ ;; - Flatten sub-patterns first: (or (or A B) (or C D)) -> (or A B C D)
+ ;; in order to improve effectiveness of regexp-opt.
+ ;; This would also help composability.
+ ;;
+ ;; - Use associativity to run regexp-opt on contiguous subsets of arguments
+ ;; if not all of them are strings. Example:
+ ;; (or (+ digit) "CHARLIE" "CHAN" (+ blank))
+ ;; -> (or (+ digit) (or "CHARLIE" "CHAN") (+ blank))
+ ;;
+ ;; - Fuse patterns into a single character alternative if they fit.
+ ;; regexp-opt will do that if all are strings, but we want to do that for:
+ ;; * symbols that expand to classes: space, alpha, ...
+ ;; * character alternatives: (any ...)
+ ;; * (syntax S), for some S (whitespace, word)
+ ;; so that (or "@" "%" digit (any "A-Z" space) (syntax word))
+ ;; -> (any "@" "%" digit "A-Z" space word)
+ ;; -> "[A-Z@%[:digit:][:space:][:word:]]"
+ ;;
+ ;; Problem: If a subpattern is carefully written to to be
+ ;; optimisable by regexp-opt, how do we prevent the transforms
+ ;; above from destroying that property?
+ ;; Example: (or "a" (or "abc" "abd" "abe"))
(cond
- ;; for some repetition
- ((eq group '*) (if (rx-atomic-p regexp) (setq group nil)))
- ;; for concatenation
- ((eq group ':)
- (if (rx-atomic-p
- (if (and (stringp regexp)
- (string-match
- "\\(?:[?*+]\\??\\|\\\\{[0-9]*,?[0-9]*\\\\}\\)\\'" regexp))
- (substring regexp 0 (match-beginning 0))
- regexp))
- (setq group nil)))
- ;; for OR
- ((eq group '|) (setq group nil))
- ;; do anyway
- ((eq group t))
- ((rx-atomic-p regexp t) (setq group nil)))
- (cond ((and group (stringp regexp))
- (concat "\\(?:" regexp "\\)"))
- (group `("\\(?:" ,@regexp "\\)"))
- (t regexp)))
-
-
-(defvar rx-parent)
-;; dynamically bound in some functions.
-
-
-(defun rx-and (form)
- "Parse and produce code from FORM.
-FORM is of the form `(and FORM1 ...)'."
- (rx-check form)
- (rx-group-if
- (rx--subforms (cdr form) ':)
- (and (memq rx-parent '(* t)) rx-parent)))
-
-
-(defun rx-or (form)
- "Parse and produce code from FORM, which is `(or FORM1 ...)'."
- (rx-check form)
- (rx-group-if
- (cond
- ((null (cdr form)) regexp-unmatchable)
- ((cl-every #'stringp (cdr form))
- (regexp-opt (cdr form) nil t))
- (t (rx--subforms (cdr form) '| "\\|")))
- (and (memq rx-parent '(: * t)) rx-parent)))
-
-
-(defun rx-anything (form)
- "Match any character."
- (if (consp form)
- (error "rx `anything' syntax error: %s" form))
- (rx-or (list 'or 'not-newline ?\n)))
-
-
-(defun rx-any-delete-from-range (char ranges)
- "Delete by side effect character CHAR from RANGES.
-Only both edges of each range is checked."
- (let (m)
- (cond
- ((memq char ranges) (setq ranges (delq char ranges)))
- ((setq m (assq char ranges))
- (if (eq (1+ char) (cdr m))
- (setcar (memq m ranges) (1+ char))
- (setcar m (1+ char))))
- ((setq m (rassq char ranges))
- (if (eq (1- char) (car m))
- (setcar (memq m ranges) (1- char))
- (setcdr m (1- char)))))
- ranges))
-
-
-(defun rx-any-condense-range (args)
- "Condense by side effect ARGS as range for Rx `any'."
- (let (str
- l)
- ;; set STR list of all strings
- ;; set L list of all ranges
- (mapc (lambda (e) (cond ((stringp e) (push e str))
- ((numberp e) (push (cons e e) l))
- ;; Ranges between ASCII and raw bytes are split,
- ;; to prevent accidental inclusion of Unicode
- ;; characters later on.
- ((and (<= (car e) #x7f)
- (>= (cdr e) #x3fff80))
- (push (cons (car e) #x7f) l)
- (push (cons #x3fff80 (cdr e)) l))
- (t (push e l))))
- args)
- ;; condense overlapped ranges in L
- (let ((tail (setq l (sort l #'car-less-than-car)))
- d)
- (while (setq d (cdr tail))
- (if (>= (cdar tail) (1- (caar d)))
- (progn
- (setcdr (car tail) (max (cdar tail) (cdar d)))
- (setcdr tail (cdr d)))
- (setq tail d))))
- ;; Separate small ranges to single number, and delete dups.
- (nconc
- (apply #'nconc
- (mapcar (lambda (e)
- (cond
- ((= (car e) (cdr e)) (list (car e)))
- ((= (1+ (car e)) (cdr e)) (list (car e) (cdr e)))
- ((list e))))
- l))
- (delete-dups str))))
-
-
-(defun rx-check-any-string (str)
- "Turn the `any' argument string STR into a list of characters.
-The original order is not preserved. Ranges, \"A-Z\", become pairs, (?A . ?Z)."
+ ((null body) ; No items: a never-matching regexp.
+ (rx--empty))
+ ((null (cdr body)) ; Single item.
+ (rx--translate (car body)))
+ ((rx--every #'stringp body) ; All strings.
+ (cons (list (regexp-opt body nil t))
+ t))
+ (t
+ (cons (append (car (rx--translate (car body)))
+ (mapcan (lambda (item)
+ (cons "\\|" (car (rx--translate item))))
+ (cdr body)))
+ nil))))
+
+(defun rx--string-to-intervals (str)
+ "Decode STR as intervals: A-Z becomes (?A . ?Z), and the single
+character X becomes (?X . ?X). Return the intervals in a list."
+ ;; We could just do string-to-multibyte on the string and work with
+ ;; that instead of this `decode-char' workaround.
(let ((decode-char
- ;; Make sure raw bytes are decoded as such, to avoid confusion with
- ;; U+0080..U+00FF.
(if (multibyte-string-p str)
#'identity
- (lambda (c) (if (<= #x80 c #xff)
- (+ c #x3fff00)
- c))))
+ #'unibyte-char-to-multibyte))
(len (length str))
(i 0)
- (ret nil))
- (if (= 0 len)
- (error "String arg for Rx `any' must not be empty"))
+ (intervals nil))
(while (< i len)
(cond ((and (< i (- len 2))
- (= (aref str (+ i 1)) ?-))
+ (= (aref str (1+ i)) ?-))
;; Range.
(let ((start (funcall decode-char (aref str i)))
(end (funcall decode-char (aref str (+ i 2)))))
- (cond ((< start end) (push (cons start end) ret))
- ((= start end) (push start ret))
+ (cond ((and (<= start #x7f) (>= end #x3fff80))
+ ;; Ranges between ASCII and raw bytes are split to
+ ;; avoid having them absorb Unicode characters
+ ;; caught in-between.
+ (push (cons start #x7f) intervals)
+ (push (cons #x3fff80 end) intervals))
+ ((<= start end)
+ (push (cons start end) intervals))
(t
- (error "Rx character range `%c-%c' is reversed"
- start end)))
+ (error "Invalid rx `any' range: %s"
+ (substring str i 3))))
(setq i (+ i 3))))
(t
;; Single character.
- (push (funcall decode-char (aref str i)) ret)
+ (let ((char (funcall decode-char (aref str i))))
+ (push (cons char char) intervals))
(setq i (+ i 1)))))
- ret))
-
-
-(defun rx-check-any (arg)
- "Check arg ARG for Rx `any'."
- (cond
- ((integerp arg) (list arg))
- ((symbolp arg)
- (let ((translation (condition-case nil
- (rx-form arg)
- (error nil))))
- (if (or (null translation)
- (null (string-match "\\`\\[\\[:[-a-z]+:\\]\\]\\'" translation)))
- (error "Invalid char class `%s' in Rx `any'" arg))
- (list (substring translation 1 -1)))) ; strip outer brackets
- ((and (characterp (car-safe arg)) (characterp (cdr-safe arg)))
- (unless (<= (car arg) (cdr arg))
- (error "Rx character range `%c-%c' is reversed"
- (car arg) (cdr arg)))
- (list arg))
- ((stringp arg) (rx-check-any-string arg))
- ((error
- "rx `any' requires string, character, char pair or char class args"))))
-
-
-(defun rx-any (form)
- "Parse and produce code from FORM, which is `(any ARG ...)'.
-ARG is optional."
- (rx-check form)
- (let* ((args (rx-any-condense-range
- (apply
- #'nconc
- (mapcar #'rx-check-any (cdr form)))))
- m
- s)
- (cond
- ;; single close bracket
- ;; => "[]...-]" or "[]...--.]"
- ((memq ?\] args)
- ;; set ] at the beginning
- (setq args (cons ?\] (delq ?\] args)))
- ;; set - at the end
- (if (or (memq ?- args) (assq ?- args))
- (setq args (nconc (rx-any-delete-from-range ?- args)
- (list ?-)))))
- ;; close bracket starts a range
- ;; => "[]-....-]" or "[]-.--....]"
- ((setq m (assq ?\] args))
- ;; bring it to the beginning
- (setq args (cons m (delq m args)))
- (cond ((memq ?- args)
- ;; to the end
- (setq args (nconc (delq ?- args) (list ?-))))
- ((setq m (assq ?- args))
- ;; next to the bracket's range, make the second range
- (setcdr args (cons m (delq m (cdr args)))))))
- ;; bracket in the end range
- ;; => "[]...-]"
- ((setq m (rassq ?\] args))
- ;; set ] at the beginning
- (setq args (cons ?\] (rx-any-delete-from-range ?\] args)))
- ;; set - at the end
- (if (or (memq ?- args) (assq ?- args))
- (setq args (nconc (rx-any-delete-from-range ?- args)
- (list ?-)))))
- ;; {no close bracket appears}
- ;;
- ;; bring single bar to the beginning
- ((memq ?- args)
- (setq args (cons ?- (delq ?- args))))
- ;; bar start a range, bring it to the beginning
- ((setq m (assq ?- args))
- (setq args (cons m (delq m args))))
- ;;
- ;; hat at the beginning?
- ((or (eq (car args) ?^) (eq (car-safe (car args)) ?^))
- (setq args (if (cdr args)
- `(,(cadr args) ,(car args) ,@(cddr args))
- (nconc (rx-any-delete-from-range ?^ args)
- (list ?^))))))
- ;; some 1-char?
- (if (and (null (cdr args)) (numberp (car args))
- (or (= 1 (length
- (setq s (regexp-quote (string (car args))))))
- (and (equal (car args) ?^) ;; unnecessary predicate?
- (null (eq rx-parent '!)))))
- s
- (concat "["
- (mapconcat
- (lambda (e) (cond
- ((numberp e) (string e))
- ((consp e)
- (if (and (= (1+ (car e)) (cdr e))
- ;; rx-any-condense-range should
- ;; prevent this case from happening.
- (null (memq (car e) '(?\] ?-)))
- (null (memq (cdr e) '(?\] ?-))))
- (string (car e) (cdr e))
- (string (car e) ?- (cdr e))))
- (e)))
- args
- nil)
- "]"))))
-
-
-(defun rx-check-not (arg)
- "Check arg ARG for Rx `not'."
- (unless (or (and (symbolp arg)
- (string-match "\\`\\[\\[:[-a-z]+:\\]\\]\\'"
- (condition-case nil
- (rx-form arg)
- (error ""))))
- (eq arg 'word-boundary)
- (and (consp arg)
- (memq (car arg) '(not any in syntax category))))
- (error "rx `not' syntax error: %s" arg))
- t)
-
-
-(defun rx-not (form)
- "Parse and produce code from FORM. FORM is `(not ...)'."
- (rx-check form)
- (let ((result (rx-form (cadr form) '!))
- case-fold-search)
- (cond ((string-match "\\`\\[\\^" result)
- (cond
- ((equal result "[^]") "[^^]")
- ((and (= (length result) 4) (null (eq rx-parent '!)))
- (regexp-quote (substring result 2 3)))
- ((concat "[" (substring result 2)))))
- ((eq ?\[ (aref result 0))
- (concat "[^" (substring result 1)))
- ((string-match "\\`\\\\[scbw]" result)
- (concat (upcase (substring result 0 2))
- (substring result 2)))
- ((string-match "\\`\\\\[SCBW]" result)
- (concat (downcase (substring result 0 2))
- (substring result 2)))
- (t
- (concat "[^" result "]")))))
-
-
-(defun rx-not-char (form)
- "Parse and produce code from FORM. FORM is `(not-char ...)'."
- (rx-check form)
- (rx-not `(not (in ,@(cdr form)))))
-
-
-(defun rx-not-syntax (form)
- "Parse and produce code from FORM. FORM is `(not-syntax SYNTAX)'."
- (rx-check form)
- (rx-not `(not (syntax ,@(cdr form)))))
-
-
-(defun rx-trans-forms (form &optional skip)
- "If FORM's length is greater than two, transform it to length two.
-A form (HEAD REST ...) becomes (HEAD (and REST ...)).
-If SKIP is non-nil, allow that number of items after the head, i.e.
-`(= N REST ...)' becomes `(= N (and REST ...))' if SKIP is 1."
- (unless skip (setq skip 0))
- (let ((tail (nthcdr (1+ skip) form)))
- (if (= (length tail) 1)
- form
- (let ((form (copy-sequence form)))
- (setcdr (nthcdr skip form) (list (cons 'and tail)))
- form))))
-
-
-(defun rx-= (form)
- "Parse and produce code from FORM `(= N ...)'."
- (rx-check form)
- (setq form (rx-trans-forms form 1))
- (unless (and (integerp (nth 1 form))
- (> (nth 1 form) 0))
- (error "rx `=' requires positive integer first arg"))
- (let ((subform (rx-form (nth 2 form) '*)))
- (if (stringp subform)
- (format "%s\\{%d\\}" subform (nth 1 form))
- `(,@subform ,(format "\\{%d\\}" (nth 1 form))))))
-
-
-(defun rx->= (form)
- "Parse and produce code from FORM `(>= N ...)'."
- (rx-check form)
- (setq form (rx-trans-forms form 1))
- (unless (and (integerp (nth 1 form))
- (> (nth 1 form) 0))
- (error "rx `>=' requires positive integer first arg"))
- (let ((subform (rx-form (nth 2 form) '*)))
- (if (stringp subform)
- (format "%s\\{%d,\\}" subform (nth 1 form))
- `(,@subform ,(format "\\{%d,\\}" (nth 1 form))))))
-
-
-(defun rx-** (form)
- "Parse and produce code from FORM `(** N M ...)'."
- (rx-check form)
- (rx-form (cons 'repeat (cdr (rx-trans-forms form 2))) '*))
-
-
-(defun rx-repeat (form)
- "Parse and produce code from FORM.
-FORM is either `(repeat N FORM1)' or `(repeat N M FORMS...)'."
- (rx-check form)
- (if (> (length form) 4)
- (setq form (rx-trans-forms form 2)))
- (if (null (nth 2 form))
- (setq form (cons (nth 0 form) (cons (nth 1 form) (nthcdr 3 form)))))
- (cond ((= (length form) 3)
- (unless (and (integerp (nth 1 form))
- (> (nth 1 form) 0))
- (error "rx `repeat' requires positive integer first arg"))
- (let ((subform (rx-form (nth 2 form) '*)))
- (if (stringp subform)
- (format "%s\\{%d\\}" subform (nth 1 form))
- `(,@subform ,(format "\\{%d\\}" (nth 1 form))))))
- ((or (not (integerp (nth 2 form)))
- (< (nth 2 form) 0)
- (not (integerp (nth 1 form)))
- (< (nth 1 form) 0)
- (< (nth 2 form) (nth 1 form)))
- (error "rx `repeat' range error"))
- (t
- (let ((subform (rx-form (nth 3 form) '*)))
- (if (stringp subform)
- (format "%s\\{%d,%d\\}" subform (nth 1 form) (nth 2 form))
- `(,@subform ,(format "\\{%d,%d\\}" (nth 1 form) (nth 2 form))))))))
-
-
-(defun rx-submatch (form)
- "Parse and produce code from FORM, which is `(submatch ...)'."
- (let ((subforms (rx--subforms (cdr form) ':)))
- (if (stringp subforms)
- (concat "\\(" subforms "\\)")
- `("\\(" ,@subforms "\\)"))))
-
-(defun rx-submatch-n (form)
- "Parse and produce code from FORM, which is `(submatch-n N ...)'."
- (let ((n (nth 1 form))
- (subforms (rx--subforms (cddr form) ':)))
- (unless (and (integerp n) (> n 0))
- (error "rx `submatch-n' argument must be positive"))
- (if (stringp subforms)
- (concat "\\(?" (number-to-string n) ":" subforms "\\)")
- `("\\(?" ,(number-to-string n) ":" ,@subforms "\\)"))))
-
-(defun rx-backref (form)
- "Parse and produce code from FORM, which is `(backref N)'."
- (rx-check form)
- (format "\\%d" (nth 1 form)))
-
-(defun rx-check-backref (arg)
- "Check arg ARG for Rx `backref'."
- (or (and (integerp arg) (>= arg 1) (<= arg 9))
- (error "rx `backref' requires numeric 1<=arg<=9: %s" arg)))
-
-(defun rx-kleene (form)
- "Parse and produce code from FORM.
-FORM is `(OP FORM1)', where OP is one of the `zero-or-one',
-`zero-or-more' etc. operators.
-If OP is one of `*', `+', `?', produce a greedy regexp.
-If OP is one of `*?', `+?', `??', produce a non-greedy regexp.
-If OP is anything else, produce a greedy regexp if `rx-greedy-flag'
-is non-nil."
- (rx-check form)
- (setq form (rx-trans-forms form))
- (let ((suffix (cond ((memq (car form) '(* + \? ?\s)) "")
- ((memq (car form) '(*? +? \?? ??)) "?")
- (rx-greedy-flag "")
- (t "?")))
- (op (cond ((memq (car form) '(* *? 0+ zero-or-more)) "*")
- ((memq (car form) '(+ +? 1+ one-or-more)) "+")
- (t "?")))
- (subform (rx-form (cadr form) '*)))
- (rx-group-if
- (if (stringp subform)
- (concat subform op suffix)
- `(,@subform ,(concat op suffix)))
- (and (memq rx-parent '(t *)) rx-parent))))
-
-
-(defun rx-atomic-p (r &optional lax)
- "Return non-nil if regexp string R is atomic.
-An atomic regexp R is one such that a suffix operator
-appended to R will apply to all of R. For example, \"a\"
-\"[abc]\" and \"\\(ab\\|ab*c\\)\" are atomic and \"ab\",
-\"[ab]c\", and \"ab\\|ab*c\" are not atomic.
-
-This function may return false negatives, but it will not
-return false positives. It is nevertheless useful in
-situations where an efficiency shortcut can be taken only if a
-regexp is atomic. The function can be improved to detect
-more cases of atomic regexps. Presently, this function
-detects the following categories of atomic regexp;
-
- a group or shy group: \\(...\\)
- a character class: [...]
- a single character: a
-
-On the other hand, false negatives will be returned for
-regexps that are atomic but end in operators, such as
-\"a+\". I think these are rare. Probably such cases could
-be detected without much effort. A guarantee of no false
-negatives would require a theoretic specification of the set
-of all atomic regexps."
- (if (and rx--compile-to-lisp
- (not (stringp r)))
- nil ;; Runtime value, we must assume non-atomic.
- (let ((l (length r)))
+ intervals))
+
+(defun rx--condense-intervals (intervals)
+ "Merge adjacent and overlapping intervals by mutation, preserving the order.
+INTERVALS is a list of (START . END) with START ≤ END, sorted by START."
+ (let ((tail intervals)
+ d)
+ (while (setq d (cdr tail))
+ (if (>= (cdar tail) (1- (caar d)))
+ (progn
+ (setcdr (car tail) (max (cdar tail) (cdar d)))
+ (setcdr tail (cdr d)))
+ (setq tail d)))
+ intervals))
+
+;; FIXME: Consider expanding definitions inside (any ...) and (not ...),
+;; and perhaps allow (any ...) inside (any ...).
+;; It would be benefit composability (build a character alternative by pieces)
+;; and be handy for obtaining the complement of a defined set of
+;; characters. (See, for example, python.el:421, `not-simple-operator'.)
+;; (Expansion in other non-rx positions is probably not a good idea:
+;; syntax, category, backref, and the integer parameters of group-n,
+;; =, >=, **, repeat)
+;; Similar effect could be attained by ensuring that
+;; (or (any X) (any Y)) -> (any X Y), and find a way to compose negative
+;; sets. `and' is taken, but we could add
+;; (intersection (not (any X)) (not (any Y))) -> (not (any X Y)).
+
+(defun rx--translate-any (negated body)
+ "Translate an (any ...) construct. Return (REGEXP . PRECEDENCE).
+If NEGATED, negate the sense."
+ (let ((classes nil)
+ (strings nil)
+ (conses nil))
+ ;; Collect strings, conses and characters, and classes in separate bins.
+ (dolist (arg body)
+ (cond ((stringp arg)
+ (push arg strings))
+ ((and (consp arg)
+ (characterp (car arg))
+ (characterp (cdr arg))
+ (<= (car arg) (cdr arg)))
+ ;; Copy the cons, in case we need to modify it.
+ (push (cons (car arg) (cdr arg)) conses))
+ ((characterp arg)
+ (push (cons arg arg) conses))
+ ((and (symbolp arg)
+ (let ((class (cdr (assq arg rx--char-classes))))
+ (and class (push class classes)))))
+ (t (error "Invalid rx `any' argument: %s" arg))))
+ (let ((items
+ ;; Translate strings and conses into nonoverlapping intervals,
+ ;; and add classes as symbols at the end.
+ (append
+ (rx--condense-intervals
+ (sort (append conses
+ (mapcan #'rx--string-to-intervals strings))
+ #'car-less-than-car))
+ (reverse classes))))
+
+ ;; Move lone ] and range ]-x to the start.
+ (let ((rbrac-l (assq ?\] items)))
+ (when rbrac-l
+ (setq items (cons rbrac-l (delq rbrac-l items)))))
+
+ ;; Split x-] and move the lone ] to the start.
+ (let ((rbrac-r (rassq ?\] items)))
+ (when (and rbrac-r (not (eq (car rbrac-r) ?\])))
+ (setcdr rbrac-r ?\\)
+ (setq items (cons '(?\] . ?\]) items))))
+
+ ;; Split ,-- (which would end up as ,- otherwise).
+ (let ((dash-r (rassq ?- items)))
+ (when (eq (car dash-r) ?,)
+ (setcdr dash-r ?,)
+ (setq items (nconc items '((?- . ?-))))))
+
+ ;; Remove - (lone or at start of interval)
+ (let ((dash-l (assq ?- items)))
+ (when dash-l
+ (if (eq (cdr dash-l) ?-)
+ (setq items (delq dash-l items)) ; Remove lone -
+ (setcar dash-l ?.)) ; Reduce --x to .-x
+ (setq items (nconc items '((?- . ?-))))))
+
+ ;; Deal with leading ^ and range ^-x.
+ (when (and (consp (car items))
+ (eq (caar items) ?^)
+ (cdr items))
+ ;; Move ^ and ^-x to second place.
+ (setq items (cons (cadr items)
+ (cons (car items) (cddr items)))))
+
(cond
- ((<= l 1))
- ((= l 2) (= (aref r 0) ?\\))
- ((= l 3) (string-match "\\`\\(?:\\\\[cCsS_]\\|\\[[^^]\\]\\)" r))
- ((null lax)
- (cond
- ((string-match "\\`\\[\\^?]?\\(?:\\[:[a-z]+:]\\|[^]]\\)*]\\'" r))
- ((string-match "\\`\\\\(\\(?:[^\\]\\|\\\\[^)]\\)*\\\\)\\'" r))))))))
-
-
-(defun rx-syntax (form)
- "Parse and produce code from FORM, which is `(syntax SYMBOL)'."
- (rx-check form)
- (let* ((sym (cadr form))
- (syntax (cdr (assq sym rx-syntax))))
+ ;; Empty set: if negated, any char, otherwise match-nothing.
+ ((null items)
+ (if negated
+ (rx--translate-symbol 'anything)
+ (rx--empty)))
+ ;; Single non-negated character.
+ ((and (null (cdr items))
+ (consp (car items))
+ (eq (caar items) (cdar items))
+ (not negated))
+ (cons (list (regexp-quote (char-to-string (caar items))))
+ t))
+ ;; At least one character or class, possibly negated.
+ (t
+ (cons
+ (list
+ (concat
+ "["
+ (and negated "^")
+ (mapconcat (lambda (item)
+ (cond ((symbolp item)
+ (format "[:%s:]" item))
+ ((eq (car item) (cdr item))
+ (char-to-string (car item)))
+ ((eq (1+ (car item)) (cdr item))
+ (string (car item) (cdr item)))
+ (t
+ (string (car item) ?- (cdr item)))))
+ items nil)
+ "]"))
+ t))))))
+
+(defun rx--translate-not (negated body)
+ "Translate a (not ...) construct. Return (REGEXP . PRECEDENCE).
+If NEGATED, negate the sense (thus making it positive)."
+ (unless (and body (null (cdr body)))
+ (error "rx `not' form takes exactly one argument"))
+ (let ((arg (car body)))
+ (cond
+ ((consp arg)
+ (pcase (car arg)
+ ((or 'any 'in 'char) (rx--translate-any (not negated) (cdr arg)))
+ ('syntax (rx--translate-syntax (not negated) (cdr arg)))
+ ('category (rx--translate-category (not negated) (cdr arg)))
+ ('not (rx--translate-not (not negated) (cdr arg)))
+ (_ (error "Illegal argument to rx `not': %S" arg))))
+ ((eq arg 'word-boundary)
+ (rx--translate-symbol
+ (if negated 'word-boundary 'not-word-boundary)))
+ (t
+ (let ((class (cdr (assq arg rx--char-classes))))
+ (if class
+ (rx--translate-any (not negated) (list class))
+ (error "Illegal argument to rx `not': %s" arg)))))))
+
+(defun rx--atomic-regexp (item)
+ "ITEM is (REGEXP . PRECEDENCE); return a regexp of precedence t."
+ (if (eq (cdr item) t)
+ (car item)
+ (rx--bracket (car item))))
+
+(defun rx--translate-counted-repetition (min-count max-count body)
+ (let ((operand (rx--translate-seq body)))
+ (if (car operand)
+ (cons (append
+ (rx--atomic-regexp operand)
+ (list (concat "\\{"
+ (number-to-string min-count)
+ (cond ((null max-count) ",")
+ ((< min-count max-count)
+ (concat "," (number-to-string max-count))))
+ "\\}")))
+ t)
+ operand)))
+
+(defun rx--check-repeat-arg (name min-args body)
+ (unless (>= (length body) min-args)
+ (error "rx `%s' requires at least %d argument%s"
+ name min-args (if (= min-args 1) "" "s")))
+ ;; There seems to be no reason to disallow zero counts.
+ (unless (natnump (car body))
+ (error "rx `%s' first argument must be nonnegative" name)))
+
+(defun rx--translate-bounded-repetition (name body)
+ (let ((min-count (car body))
+ (max-count (cadr body))
+ (items (cddr body)))
+ (unless (and (natnump min-count)
+ (natnump max-count)
+ (<= min-count max-count))
+ (error "rx `%s' range error" name))
+ (rx--translate-counted-repetition min-count max-count items)))
+
+(defun rx--translate-repeat (body)
+ (rx--check-repeat-arg 'repeat 2 body)
+ (if (= (length body) 2)
+ (rx--translate-counted-repetition (car body) (car body) (cdr body))
+ (rx--translate-bounded-repetition 'repeat body)))
+
+(defun rx--translate-** (body)
+ (rx--check-repeat-arg '** 2 body)
+ (rx--translate-bounded-repetition '** body))
+
+(defun rx--translate->= (body)
+ (rx--check-repeat-arg '>= 1 body)
+ (rx--translate-counted-repetition (car body) nil (cdr body)))
+
+(defun rx--translate-= (body)
+ (rx--check-repeat-arg '= 1 body)
+ (rx--translate-counted-repetition (car body) (car body) (cdr body)))
+
+(defvar rx--greedy t)
+
+(defun rx--translate-rep (op-string greedy body)
+ "Translate a repetition; OP-STRING is one of \"*\", \"+\" or \"?\".
+GREEDY is a boolean. Return (REGEXP . PRECEDENCE)."
+ (let ((operand (rx--translate-seq body)))
+ (if (car operand)
+ (cons (append (rx--atomic-regexp operand)
+ (list (concat op-string (unless greedy "?"))))
+ ;; The result has precedence seq to avoid (? (* "a")) -> "a*?"
+ 'seq)
+ operand)))
+
+(defun rx--control-greedy (greedy body)
+ "Translate the sequence BODY with greediness GREEDY.
+Return (REGEXP . PRECEDENCE)."
+ (let ((rx--greedy greedy))
+ (rx--translate-seq body)))
+
+(defun rx--translate-group (body)
+ "Translate the `group' form. Return (REGEXP . PRECEDENCE)."
+ (cons (rx--enclose "\\("
+ (car (rx--translate-seq body))
+ "\\)")
+ t))
+
+(defun rx--translate-group-n (body)
+ "Translate the `group-n' form. Return (REGEXP . PRECEDENCE)."
+ (unless (and (integerp (car body)) (> (car body) 0))
+ (error "rx `group-n' requires a positive number as first argument"))
+ (cons (rx--enclose (concat "\\(?" (number-to-string (car body)) ":")
+ (car (rx--translate-seq (cdr body)))
+ "\\)")
+ t))
+
+(defun rx--translate-backref (body)
+ "Translate the `backref' form. Return (REGEXP . PRECEDENCE)."
+ (unless (and (= (length body) 1) (integerp (car body)) (<= 1 (car body) 9))
+ (error "rx `backref' requires an argument in the range 1..9"))
+ (cons (list "\\" (number-to-string (car body))) t))
+
+(defconst rx--syntax-codes
+ '((whitespace . ?-) ; SPC also accepted
+ (punctuation . ?.)
+ (word . ?w) ; W also accepted
+ (symbol . ?_)
+ (open-parenthesis . ?\()
+ (close-parenthesis . ?\))
+ (expression-prefix . ?\')
+ (string-quote . ?\")
+ (paired-delimiter . ?$)
+ (escape . ?\\)
+ (character-quote . ?/)
+ (comment-start . ?<)
+ (comment-end . ?>)
+ (string-delimiter . ?|)
+ (comment-delimiter . ?!)))
+
+(defun rx--translate-syntax (negated body)
+ "Translate the `syntax' form. Return (REGEXP . PRECEDENCE)."
+ (unless (and body (null (cdr body)))
+ (error "rx `syntax' form takes exactly one argument"))
+ (let* ((sym (car body))
+ (syntax (cdr (assq sym rx--syntax-codes))))
(unless syntax
- ;; Try sregex compatibility.
(cond
- ((characterp sym) (setq syntax sym))
+ ;; Syntax character directly (sregex compatibility)
+ ((and (characterp sym) (rassq sym rx--syntax-codes))
+ (setq syntax sym))
+ ;; Syntax character as symbol (sregex compatibility)
((symbolp sym)
(let ((name (symbol-name sym)))
- (if (= 1 (length name))
- (setq syntax (aref name 0))))))
+ (when (= (length name) 1)
+ (let ((char (string-to-char name)))
+ (when (rassq char rx--syntax-codes)
+ (setq syntax char)))))))
(unless syntax
- (error "Unknown rx syntax `%s'" sym)))
- (format "\\s%c" syntax)))
-
-
-(defun rx-check-category (form)
- "Check the argument FORM of a `(category FORM)'."
- (unless (or (integerp form)
- (cdr (assq form rx-categories)))
- (error "Unknown category `%s'" form))
- t)
-
-
-(defun rx-category (form)
- "Parse and produce code from FORM, which is `(category SYMBOL)'."
- (rx-check form)
- (let ((char (if (integerp (cadr form))
- (cadr form)
- (cdr (assq (cadr form) rx-categories)))))
- (format "\\c%c" char)))
-
-
-(defun rx-eval (form)
- "Parse and produce code from FORM, which is `(eval FORM)'."
- (rx-check form)
- (rx-form (eval (cadr form)) rx-parent))
-
-
-(defun rx-greedy (form)
- "Parse and produce code from FORM.
-If FORM is `(minimal-match FORM1)', non-greedy versions of `*',
-`+', and `?' operators will be used in FORM1. If FORM is
-`(maximal-match FORM1)', greedy operators will be used."
- (rx-check form)
- (let ((rx-greedy-flag (eq (car form) 'maximal-match)))
- (rx-form (cadr form) rx-parent)))
-
-
-(defun rx-regexp (form)
- "Parse and produce code from FORM, which is `(regexp STRING)'."
- (cond ((stringp (cadr form))
- (rx-group-if (cadr form) rx-parent))
- (rx--compile-to-lisp
- ;; Always group non-string forms, since we can't be sure they
- ;; are atomic.
- (rx-group-if (cdr form) t))
- (t (rx-check form))))
-
-(defun rx-literal (form)
- "Parse and produce code from FORM, which is `(literal STRING-EXP)'."
- (cond ((stringp (cadr form))
- ;; This is allowed, but makes little sense, you could just
- ;; use STRING directly.
- (rx-group-if (regexp-quote (cadr form)) rx-parent))
- (rx--compile-to-lisp
- (rx-group-if `((regexp-quote ,(cadr form))) rx-parent))
- (t (rx-check form))))
-
-(defun rx-form (form &optional parent)
- "Parse and produce code for regular expression FORM.
-FORM is a regular expression in sexp form.
-PARENT shows which type of expression calls and controls putting of
-shy groups around the result and some more in other functions."
- (let ((rx-parent parent))
- (cond
- ((stringp form)
- (rx-group-if (regexp-quote form)
- (if (and (eq parent '*) (< 1 (length form)))
- parent)))
- ((integerp form)
- (regexp-quote (char-to-string form)))
- ((symbolp form)
- (let ((info (rx-info form nil)))
- (cond ((stringp info)
- info)
- ((null info)
- (error "Unknown rx form `%s'" form))
- (t
- (funcall (nth 0 info) form)))))
- ((consp form)
- (let ((info (rx-info (car form) 'head)))
- (unless (consp info)
- (error "Unknown rx form `%s'" (car form)))
- (funcall (nth 0 info) form)))
- (t
- (error "rx syntax error at `%s'" form)))))
-
-(defun rx--subforms (subforms &optional parent separator)
- "Produce code for regular expressions SUBFORMS.
-SUBFORMS is a list of regular expression sexps.
-PARENT controls grouping, as in `rx-form'.
-Insert SEPARATOR between the code from each of SUBFORMS."
- (if (null (cdr subforms))
- ;; Zero or one forms, no need for grouping.
- (and subforms (rx-form (car subforms)))
- (let ((listify (lambda (x)
- (if (listp x) (copy-sequence x)
- (list x)))))
- (setq subforms (mapcar (lambda (x) (rx-form x parent)) subforms))
- (cond ((or (not rx--compile-to-lisp)
- (cl-every #'stringp subforms))
- (mapconcat #'identity subforms separator))
- (separator
- (nconc (funcall listify (car subforms))
- (mapcan (lambda (x)
- (cons separator (funcall listify x)))
- (cdr subforms))))
- (t (mapcan listify subforms))))))
+ (error "Unknown rx syntax name `%s'" sym)))
+ (cons (list (string ?\\ (if negated ?S ?s) syntax))
+ t)))
+
+(defconst rx--categories
+ '((space-for-indent . ?\s)
+ (base . ?.)
+ (consonant . ?0)
+ (base-vowel . ?1)
+ (upper-diacritical-mark . ?2)
+ (lower-diacritical-mark . ?3)
+ (tone-mark . ?4)
+ (symbol . ?5)
+ (digit . ?6)
+ (vowel-modifying-diacritical-mark . ?7)
+ (vowel-sign . ?8)
+ (semivowel-lower . ?9)
+ (not-at-end-of-line . ?<)
+ (not-at-beginning-of-line . ?>)
+ (alpha-numeric-two-byte . ?A)
+ (chinese-two-byte . ?C)
+ (chinse-two-byte . ?C) ; A typo in Emacs 21.1-24.3.
+ (greek-two-byte . ?G)
+ (japanese-hiragana-two-byte . ?H)
+ (indian-two-byte . ?I)
+ (japanese-katakana-two-byte . ?K)
+ (strong-left-to-right . ?L)
+ (korean-hangul-two-byte . ?N)
+ (strong-right-to-left . ?R)
+ (cyrillic-two-byte . ?Y)
+ (combining-diacritic . ?^)
+ (ascii . ?a)
+ (arabic . ?b)
+ (chinese . ?c)
+ (ethiopic . ?e)
+ (greek . ?g)
+ (korean . ?h)
+ (indian . ?i)
+ (japanese . ?j)
+ (japanese-katakana . ?k)
+ (latin . ?l)
+ (lao . ?o)
+ (tibetan . ?q)
+ (japanese-roman . ?r)
+ (thai . ?t)
+ (vietnamese . ?v)
+ (hebrew . ?w)
+ (cyrillic . ?y)
+ (can-break . ?|)))
+
+(defun rx--translate-category (negated body)
+ "Translate the `category' form. Return (REGEXP . PRECEDENCE)."
+ (unless (and body (null (cdr body)))
+ (error "rx `category' form takes exactly one argument"))
+ (let* ((arg (car body))
+ (category
+ (cond ((symbolp arg)
+ (let ((cat (assq arg rx--categories)))
+ (unless cat
+ (error "Unknown rx category `%s'" arg))
+ (cdr cat)))
+ ((characterp arg) arg)
+ (t (error "Invalid rx `category' argument `%s'" arg)))))
+ (cons (list (string ?\\ (if negated ?C ?c) category))
+ t)))
+
+(defvar rx--delayed-evaluation nil
+ "Whether to allow certain forms to be evaluated at runtime.")
+
+(defun rx--translate-literal (body)
+ "Translate the `literal' form. Return (REGEXP . PRECEDENCE)."
+ (unless (and body (null (cdr body)))
+ (error "rx `literal' form takes exactly one argument"))
+ (let ((arg (car body)))
+ (cond ((stringp arg)
+ (cons (list (regexp-quote arg)) (if (= (length arg) 1) t 'seq)))
+ (rx--delayed-evaluation
+ (cons (list (list 'regexp-quote arg)) 'seq))
+ (t (error "rx `literal' form with non-string argument")))))
+
+(defun rx--translate-eval (body)
+ "Translate the `eval' form. Return (REGEXP . PRECEDENCE)."
+ (unless (and body (null (cdr body)))
+ (error "rx `eval' form takes exactly one argument"))
+ (rx--translate (eval (car body))))
+
+(defvar rx--regexp-atomic-regexp nil)
+
+(defun rx--translate-regexp (body)
+ "Translate the `regexp' form. Return (REGEXP . PRECEDENCE)."
+ (unless (and body (null (cdr body)))
+ (error "rx `regexp' form takes exactly one argument"))
+ (let ((arg (car body)))
+ (cond ((stringp arg)
+ ;; Generate the regexp when needed, since rx isn't
+ ;; necessarily present in the byte-compilation environment.
+ (unless rx--regexp-atomic-regexp
+ (setq rx--regexp-atomic-regexp
+ ;; Match atomic (precedence t) regexps: may give
+ ;; false negatives but no false positives, assuming
+ ;; the target string is syntactically correct.
+ (rx-to-string
+ '(seq
+ bos
+ (or (seq "["
+ (opt "^")
+ (opt "]")
+ (* (or (seq "[:" (+ (any "a-z")) ":]")
+ (not (any "]"))))
+ "]")
+ anything
+ (seq "\\"
+ (or anything
+ (seq (any "sScC_") anything)
+ (seq "("
+ (* (or (not (any "\\"))
+ (seq "\\" (not (any ")")))))
+ "\\)"))))
+ eos)
+ t)))
+ (cons (list arg)
+ (if (string-match-p rx--regexp-atomic-regexp arg) t nil)))
+ (rx--delayed-evaluation
+ (cons (list arg) nil))
+ (t (error "rx `regexp' form with non-string argument")))))
+
+(defun rx--translate-compat-form (def form)
+ "Translate a compatibility form from `rx-constituents'.
+DEF is the definition tuple. Return (REGEXP . PRECEDENCE)."
+ (let* ((fn (nth 0 def))
+ (min-args (nth 1 def))
+ (max-args (nth 2 def))
+ (predicate (nth 3 def))
+ (nargs (1- (length form))))
+ (when (< nargs min-args)
+ (error "The `%s' form takes at least %d argument(s)"
+ (car form) min-args))
+ (when (and max-args (> nargs max-args))
+ (error "The `%s' form takes at most %d argument(s)"
+ (car form) max-args))
+ (when (and predicate (not (rx--every predicate (cdr form))))
+ (error "The `%s' form requires arguments satisfying `%s'"
+ (car form) predicate))
+ (let ((regexp (funcall fn form)))
+ (unless (stringp regexp)
+ (error "The `%s' form did not expand to a string" (car form)))
+ (cons (list regexp) nil))))
+
+(defun rx--translate-form (form)
+ "Translate an rx form (list structure). Return (REGEXP . PRECEDENCE)."
+ (let ((body (cdr form)))
+ (pcase (car form)
+ ((or 'seq : 'and 'sequence) (rx--translate-seq body))
+ ((or 'or '|) (rx--translate-or body))
+ ((or 'any 'in 'char) (rx--translate-any nil body))
+ ('not-char (rx--translate-any t body))
+ ('not (rx--translate-not nil body))
+
+ ('repeat (rx--translate-repeat body))
+ ('= (rx--translate-= body))
+ ('>= (rx--translate->= body))
+ ('** (rx--translate-** body))
+
+ ((or 'zero-or-more '0+) (rx--translate-rep "*" rx--greedy body))
+ ((or 'one-or-more '1+) (rx--translate-rep "+" rx--greedy body))
+ ((or 'zero-or-one 'opt 'optional) (rx--translate-rep "?" rx--greedy body))
+
+ ('* (rx--translate-rep "*" t body))
+ ('+ (rx--translate-rep "+" t body))
+ ((or '\? ?\s) (rx--translate-rep "?" t body))
+
+ ('*? (rx--translate-rep "*" nil body))
+ ('+? (rx--translate-rep "+" nil body))
+ ((or '\?? ??) (rx--translate-rep "?" nil body))
+
+ ('minimal-match (rx--control-greedy nil body))
+ ('maximal-match (rx--control-greedy t body))
+
+ ((or 'group 'submatch) (rx--translate-group body))
+ ((or 'group-n 'submatch-n) (rx--translate-group-n body))
+ ('backref (rx--translate-backref body))
+
+ ('syntax (rx--translate-syntax nil body))
+ ('not-syntax (rx--translate-syntax t body))
+ ('category (rx--translate-category nil body))
+
+ ('literal (rx--translate-literal body))
+ ('eval (rx--translate-eval body))
+ ((or 'regexp 'regex) (rx--translate-regexp body))
+
+ (op
+ (unless (symbolp op)
+ (error "Bad rx operator `%S'" op))
+
+ ;; For compatibility with old rx.
+ (let ((entry (assq op rx-constituents)))
+ (if (progn
+ (while (and entry (not (consp (cdr entry))))
+ (setq entry
+ (if (symbolp (cdr entry))
+ ;; Alias for another entry.
+ (assq (cdr entry) rx-constituents)
+ ;; Wrong type, try further down the list.
+ (assq (car entry)
+ (cdr (memq entry rx-constituents))))))
+ entry)
+ (rx--translate-compat-form (cdr entry) form)
+ (error "Unknown rx form `%s'" op)))))))
+
+;; Defined here rather than in re-builder to lower the odds that it
+;; will be kept in sync with changes.
+(defconst rx--builtin-forms
+ '(seq sequence : and or | any in char not-char not
+ repeat = >= **
+ zero-or-more 0+ *
+ one-or-more 1+ +
+ zero-or-one opt optional \?
+ *? +? \??
+ minimal-match maximal-match
+ group submatch group-n submatch-n backref
+ syntax not-syntax category
+ literal eval regexp regex)
+ "List of built-in rx forms. For use in re-builder only.")
+
+(defun rx--translate (item)
+ "Translate the rx-expression ITEM. Return (REGEXP . PRECEDENCE)."
+ (cond
+ ((stringp item)
+ (if (= (length item) 0)
+ (cons nil 'seq)
+ (cons (list (regexp-quote item)) (if (= (length item) 1) t 'seq))))
+ ((characterp item)
+ (cons (list (regexp-quote (char-to-string item))) t))
+ ((symbolp item)
+ (rx--translate-symbol item))
+ ((consp item)
+ (rx--translate-form item))
+ (t (error "Bad rx expression: %S" item))))
;;;###autoload
(defun rx-to-string (form &optional no-group)
- "Parse and produce code for regular expression FORM.
-FORM is a regular expression in sexp form.
-NO-GROUP non-nil means don't put shy groups around the result.
-
-In contrast to the `rx' macro, subforms `literal' and `regexp'
-will not accept non-string arguments, i.e., (literal STRING)
-becomes just a more verbose version of STRING."
- (rx-group-if (rx-form form) (null no-group)))
+ "Translate FORM from `rx' sexp syntax into a string regexp.
+The arguments to `literal' and `regexp' forms inside FORM must be
+constant strings.
+If NO-GROUP is non-nil, don't bracket the result in a non-capturing
+group."
+ (let* ((item (rx--translate form))
+ (exprs (if no-group
+ (car item)
+ (rx--atomic-regexp item))))
+ (apply #'concat exprs)))
+
+(defun rx--to-expr (form)
+ "Translate the rx-expression FORM to a Lisp expression yielding a regexp."
+ (let* ((rx--delayed-evaluation t)
+ (elems (car (rx--translate form)))
+ (args nil))
+ ;; Merge adjacent strings.
+ (while elems
+ (let ((strings nil))
+ (while (and elems (stringp (car elems)))
+ (push (car elems) strings)
+ (setq elems (cdr elems)))
+ (let ((s (apply #'concat (nreverse strings))))
+ (unless (zerop (length s))
+ (push s args))))
+ (when elems
+ (push (car elems) args)
+ (setq elems (cdr elems))))
+ (cond ((null args) "") ; 0 args
+ ((cdr args) (cons 'concat (nreverse args))) ; ≥2 args
+ (t (car args))))) ; 1 arg
;;;###autoload
@@ -1054,78 +950,64 @@ rx
(literal EXPR) Match the literal string from evaluating EXPR at run time.
(regexp EXPR) Match the string regexp from evaluating EXPR at run time.
-(eval EXPR) Match the rx sexp from evaluating EXPR at compile time."
- (let* ((rx--compile-to-lisp t)
- (re (cond ((null regexps)
- (error "No regexp"))
- ((cdr regexps)
- (rx-to-string `(and ,@regexps) t))
- (t
- (rx-to-string (car regexps) t)))))
- (if (stringp re)
- re
- `(concat ,@re))))
-
+(eval EXPR) Match the rx sexp from evaluating EXPR at compile time.
+
+\(fn REGEXPS...)"
+ (rx--to-expr (cons 'seq regexps)))
+
+
+;; During `rx--pcase-transform', list of defined variables in right-to-left
+;; order.
+(defvar rx--pcase-vars)
+
+(defun rx--pcase-transform (rx)
+ "Transform RX, an rx-expression augmented with `let' and named `backref',
+into a plain rx-expression, collecting names into `rx--pcase-vars'."
+ (pcase rx
+ (`(let ,name . ,body)
+ (let* ((index (length (memq name rx--pcase-vars)))
+ (i (if (zerop index)
+ (length (push name rx--pcase-vars))
+ index)))
+ `(group-n ,i ,(rx--pcase-transform (cons 'seq body)))))
+ ((and `(backref ,ref)
+ (guard (symbolp ref)))
+ (let ((index (length (memq ref rx--pcase-vars))))
+ (when (zerop index)
+ (error "rx `backref' variable must be one of: %s"
+ (mapconcat #'symbol-name rx--pcase-vars " ")))
+ `(backref ,index)))
+ ((and `(,head . ,rest)
+ (guard (and (symbolp head)
+ (not (memq head '(literal regexp regex eval))))))
+ (cons head (mapcar #'rx--pcase-transform rest)))
+ (_ rx)))
(pcase-defmacro rx (&rest regexps)
- "Build a `pcase' pattern matching `rx' REGEXPS in sexp form.
-The REGEXPS are interpreted as in `rx'. The pattern matches any
-string that is a match for the regular expression so constructed,
-as if by `string-match'.
+ "A pattern that matches strings against `rx' REGEXPS in sexp form.
+REGEXPS are interpreted as in `rx'. The pattern matches any
+string that is a match for REGEXPS, as if by `string-match'.
-In addition to the usual `rx' constructs, REGEXPS can contain the
+In addition to the usual `rx' syntax, REGEXPS can contain the
following constructs:
- (let REF SEXP...) creates a new explicitly named reference to
- a submatch that matches regular expressions
- SEXP, and binds the match to REF.
- (backref REF) creates a backreference to the submatch
- introduced by a previous (let REF ...)
- construct. REF can be the same symbol
- in the first argument of the corresponding
- (let REF ...) construct, or it can be a
- submatch number. It matches the referenced
- submatch.
-
-The REFs are associated with explicitly named submatches starting
-from 1. Multiple occurrences of the same REF refer to the same
-submatch.
-
-If a case matches, the match data is modified as usual so you can
-use it in the case body, but you still have to pass the correct
-string as argument to `match-string'."
- (let* ((vars ())
- (rx-constituents
- `((let
- ,(lambda (form)
- (rx-check form)
- (let ((var (cadr form)))
- (cl-check-type var symbol)
- (let ((i (or (cl-position var vars :test #'eq)
- (prog1 (length vars)
- (setq vars `(,@vars ,var))))))
- (rx-form `(submatch-n ,(1+ i) ,@(cddr form))))))
- 1 nil)
- (backref
- ,(lambda (form)
- (rx-check form)
- (rx-backref
- `(backref ,(let ((var (cadr form)))
- (if (integerp var) var
- (1+ (cl-position var vars :test #'eq)))))))
- 1 1
- ,(lambda (var)
- (cond ((integerp var) (rx-check-backref var))
- ((memq var vars) t)
- (t (error "rx `backref' variable must be one of %s: %s"
- vars var)))))
- ,@rx-constituents))
- (regexp (rx-to-string `(seq ,@regexps) :no-group)))
+ (let REF RX...) binds the symbol REF to a submatch that matches
+ the regular expressions RX. REF is bound in
+ CODE to the string of the submatch or nil, but
+ can also be used in `backref'.
+ (backref REF) matches whatever the submatch REF matched.
+ REF can be a number, as usual, or a name
+ introduced by a previous (let REF ...)
+ construct."
+ (let* ((rx--pcase-vars nil)
+ (regexp (rx--to-expr (rx--pcase-transform (cons 'seq regexps)))))
`(and (pred (string-match ,regexp))
- ,@(cl-loop for i from 1
- for var in vars
- collect `(app (match-string ,i) ,var)))))
-\f
+ ,@(let ((i 0))
+ (mapcar (lambda (name)
+ (setq i (1+ i))
+ `(app (match-string ,i) ,name))
+ (reverse rx--pcase-vars))))))
+
(provide 'rx)
;;; rx.el ends here
diff --git a/test/lisp/emacs-lisp/rx-tests.el b/test/lisp/emacs-lisp/rx-tests.el
index 8845ebf46d..56c96e4c44 100644
--- a/test/lisp/emacs-lisp/rx-tests.el
+++ b/test/lisp/emacs-lisp/rx-tests.el
@@ -1,4 +1,4 @@
-;;; rx-tests.el --- test for rx.el functions -*- lexical-binding: t -*-
+;;; rx-tests.el --- tests for rx.el -*- lexical-binding: t -*-
;; Copyright (C) 2016-2019 Free Software Foundation, Inc.
@@ -17,21 +17,44 @@
;; You should have received a copy of the GNU General Public License
;; along with GNU Emacs. If not, see <https://www.gnu.org/licenses/>.
-;;; Commentary:
-
(require 'ert)
(require 'rx)
-;;; Code:
+(ert-deftest rx-seq ()
+ (should (equal (rx "a.b" "*" "c")
+ "a\\.b\\*c"))
+ (should (equal (rx (seq "a" (: "b" (and "c" (sequence "d" nonl)
+ "e")
+ "f")
+ "g"))
+ "abcd.efg"))
+ (should (equal (rx "a$" "b")
+ "a\\$b"))
+ (should (equal (rx bol "a" "b" ?c eol)
+ "^abc$"))
+ (should (equal (rx "a" "" "b")
+ "ab"))
+ (should (equal (rx (seq))
+ ""))
+ (should (equal (rx "" (or "ab" nonl) "")
+ "ab\\|.")))
+
+(ert-deftest rx-or ()
+ (should (equal (rx (or "ab" (| "c" nonl) "de"))
+ "ab\\|c\\|.\\|de"))
+ (should (equal (rx (or "ab" "abc" "a"))
+ "\\(?:ab\\|abc\\|a\\)"))
+ (should (equal (rx (| nonl "a") (| "b" blank))
+ "\\(?:.\\|a\\)\\(?:b\\|[[:blank:]]\\)"))
+ (should (equal (rx (|))
+ "\\`a\\`")))
(ert-deftest rx-char-any ()
"Test character alternatives with `]' and `-' (Bug#25123)."
- (should (string-match
+ (should (equal
(rx string-start (1+ (char (?\] . ?\{) (?< . ?\]) (?- . ?:)))
string-end)
- (apply #'string (nconc (number-sequence ?\] ?\{)
- (number-sequence ?< ?\])
- (number-sequence ?- ?:))))))
+ "\\`[.-:<-{-]+\\'")))
(ert-deftest rx-char-any-range-nl ()
"Test character alternatives with LF as a range endpoint."
@@ -40,28 +63,67 @@
(should (equal (rx (any "\a-\n"))
"[\a-\n]")))
-(ert-deftest rx-char-any-range-bad ()
- (should-error (rx (any "0-9a-Z")))
- (should-error (rx (any (?0 . ?9) (?a . ?Z)))))
-
(ert-deftest rx-char-any-raw-byte ()
"Test raw bytes in character alternatives."
;; Separate raw characters.
- (should (equal (string-match-p (rx (any "\326A\333B"))
- "X\326\333")
- 1))
+ (should (equal (rx (any "\326A\333B"))
+ (string-to-multibyte "[AB\326\333]")))
;; Range of raw characters, unibyte.
- (should (equal (string-match-p (rx (any "\200-\377"))
- "ÿA\310B")
- 2))
+ (should (equal (rx (any "\200-\377"))
+ (string-to-multibyte "[\200-\377]")))
;; Range of raw characters, multibyte.
- (should (equal (string-match-p (rx (any "Å\211\326-\377\177"))
- "XY\355\177\327")
- 2))
+ (should (equal (rx (any "Å\211\326-\377\177"))
+ "[\177Å\211\326-\377]"))
;; Split range; \177-\377ÿ should not be optimised to \177-\377.
- (should (equal (string-match-p (rx (any "\177-\377" ?ÿ))
- "ÿA\310B")
- 0)))
+ (should (equal (rx (any "\177-\377" ?ÿ))
+ "[\177ÿ\200-\377]")))
+
+(ert-deftest rx-any ()
+ (should (equal (rx (any ?A (?C . ?D) "F-H" "J-L" "M" "N-P" "Q" "RS"))
+ "[ACDF-HJ-S]"))
+ (should (equal (rx (in "a!f" ?c) (char "q-z" "0-3")
+ (not-char "a-e1-5") (not (in "A-M" ?q)))
+ "[!acf][0-3q-z][^1-5a-e][^A-Mq]"))
+ (should (equal (rx (any "^") (any "]") (any "-")
+ (not (any "^")) (not (any "]")) (not (any "-")))
+ "\\^]-[^^][^]][^-]"))
+ (should (equal (rx (any "]" "^") (any "]" "-") (any "-" "^")
+ (not (any "]" "^")) (not (any "]" "-"))
+ (not (any "-" "^")))
+ "[]^][]-][-^][^]^][^]-][^-^]"))
+ (should (equal (rx (any "]" "^" "-") (not (any "]" "^" "-")))
+ "[]^-][^]^-]"))
+ (should (equal (rx (any "-" ascii) (any "^" ascii) (any "]" ascii))
+ "[[:ascii:]-][[:ascii:]^][][:ascii:]]"))
+ (should (equal (rx (not (any "-" ascii)) (not (any "^" ascii))
+ (not (any "]" ascii)))
+ "[^[:ascii:]-][^[:ascii:]^][^][:ascii:]]"))
+ (should (equal (rx (any "-]" ascii) (any "^]" ascii) (any "-^" ascii))
+ "[][:ascii:]-][]^[:ascii:]][[:ascii:]^-]"))
+ (should (equal (rx (not (any "-]" ascii)) (not (any "^]" ascii))
+ (not (any "-^" ascii)))
+ "[^][:ascii:]-][^]^[:ascii:]][^[:ascii:]^-]"))
+ (should (equal (rx (any "-]^" ascii) (not (any "-]^" ascii)))
+ "[]^[:ascii:]-][^]^[:ascii:]-]"))
+ (should (equal (rx (any "^" lower upper) (not (any "^" lower upper)))
+ "[[:lower:]^[:upper:]][^[:lower:]^[:upper:]]"))
+ (should (equal (rx (any "-" lower upper) (not (any "-" lower upper)))
+ "[[:lower:][:upper:]-][^[:lower:][:upper:]-]"))
+ (should (equal (rx (any "]" lower upper) (not (any "]" lower upper)))
+ "[][:lower:][:upper:]][^][:lower:][:upper:]]"))
+ (should (equal (rx (any "-a" "c-" "f-f" "--/*--"))
+ "[*-/acf]"))
+ (should (equal (rx (any "]-a" ?-) (not (any "]-a" ?-)))
+ "[]-a-][^]-a-]"))
+ (should (equal (rx (any "--]") (not (any "--]"))
+ (any "-" "^-a") (not (any "-" "^-a")))
+ "[].-\\-][^].-\\-][-^-a][^-^-a]"))
+ (should (equal (rx (not (any "!a" "0-8" digit nonascii)))
+ "[^!0-8a[:digit:][:nonascii:]]"))
+ (should (equal (rx (any) (not (any)))
+ "\\`a\\`\\(?:.\\|\n\\)"))
+ (should (equal (rx (any "") (not (any "")))
+ "\\`a\\`\\(?:.\\|\n\\)")))
(ert-deftest rx-pcase ()
(should (equal (pcase "a 1 2 3 1 1 b"
@@ -71,7 +133,11 @@
(backref u) space
(backref 1))
(list u v)))
- '("1" "3"))))
+ '("1" "3")))
+ (let ((k "blue"))
+ (should (equal (pcase "<blue>"
+ ((rx "<" (literal k) ">") 'ok))
+ 'ok))))
(ert-deftest rx-kleene ()
"Test greedy and non-greedy repetition operators."
@@ -94,71 +160,158 @@
(should (equal (rx (maximal-match
(seq (* "a") (+ "b") (\? "c") (?\s "d")
(*? "e") (+? "f") (\?? "g") (?? "h"))))
- "a*b+c?d?e*?f+?g??h??")))
+ "a*b+c?d?e*?f+?g??h??"))
+ (should (equal (rx "a" (*) (+ (*)) (? (*) (+)) "b")
+ "ab")))
-(ert-deftest rx-or ()
- ;; Test or-pattern reordering (Bug#34641).
- (let ((s "abc"))
- (should (equal (and (string-match (rx (or "abc" "ab" "a")) s)
- (match-string 0 s))
- "abc"))
- (should (equal (and (string-match (rx (or "ab" "abc" "a")) s)
- (match-string 0 s))
- "ab"))
- (should (equal (and (string-match (rx (or "a" "ab" "abc")) s)
- (match-string 0 s))
- "a")))
- ;; Test zero-argument `or'.
- (should (equal (rx (or)) regexp-unmatchable)))
+(ert-deftest rx-repeat ()
+ (should (equal (rx (= 3 "a") (>= 51 "b")
+ (** 2 11 "c") (repeat 6 "d") (repeat 4 8 "e"))
+ "a\\{3\\}b\\{51,\\}c\\{2,11\\}d\\{6\\}e\\{4,8\\}"))
+ (should (equal (rx (= 0 "k") (>= 0 "l") (** 0 0 "m") (repeat 0 "n")
+ (repeat 0 0 "o"))
+ "k\\{0\\}l\\{0,\\}m\\{0\\}n\\{0\\}o\\{0\\}"))
+ (should (equal (rx (opt (0+ "a")))
+ "\\(?:a*\\)?"))
+ (should (equal (rx (opt (= 4 "a")))
+ "a\\{4\\}?"))
+ (should (equal (rx "a" (** 3 7) (= 4) (>= 3) (= 4 (>= 7) (= 2)) "b")
+ "ab")))
+
+(ert-deftest rx-atoms ()
+ (should (equal (rx anything)
+ ".\\|\n"))
+ (should (equal (rx line-start not-newline nonl any line-end)
+ "^...$"))
+ (should (equal (rx bol string-start string-end buffer-start buffer-end
+ bos eos bot eot eol)
+ "^\\`\\'\\`\\'\\`\\'\\`\\'$"))
+ (should (equal (rx point word-start word-end bow eow symbol-start symbol-end
+ word-boundary not-word-boundary not-wordchar)
+ "\\=\\<\\>\\<\\>\\_<\\_>\\b\\B\\W"))
+ (should (equal (rx digit numeric num control cntrl)
+ "[[:digit:]][[:digit:]][[:digit:]][[:cntrl:]][[:cntrl:]]"))
+ (should (equal (rx hex-digit hex xdigit blank)
+ "[[:xdigit:]][[:xdigit:]][[:xdigit:]][[:blank:]]"))
+ (should (equal (rx graph graphic print printing)
+ "[[:graph:]][[:graph:]][[:print:]][[:print:]]"))
+ (should (equal (rx alphanumeric alnum letter alphabetic alpha)
+ "[[:alnum:]][[:alnum:]][[:alpha:]][[:alpha:]][[:alpha:]]"))
+ (should (equal (rx ascii nonascii lower lower-case)
+ "[[:ascii:]][[:nonascii:]][[:lower:]][[:lower:]]"))
+ (should (equal (rx punctuation punct space whitespace white)
+ "[[:punct:]][[:punct:]][[:space:]][[:space:]][[:space:]]"))
+ (should (equal (rx upper upper-case word wordchar)
+ "[[:upper:]][[:upper:]][[:word:]][[:word:]]"))
+ (should (equal (rx unibyte multibyte)
+ "[[:unibyte:]][[:multibyte:]]")))
+
+(ert-deftest rx-syntax ()
+ (should (equal (rx (syntax whitespace) (syntax punctuation)
+ (syntax word) (syntax symbol)
+ (syntax open-parenthesis) (syntax close-parenthesis))
+ "\\s-\\s.\\sw\\s_\\s(\\s)"))
+ (should (equal (rx (syntax string-quote) (syntax paired-delimiter)
+ (syntax escape) (syntax character-quote)
+ (syntax comment-start) (syntax comment-end)
+ (syntax string-delimiter) (syntax comment-delimiter))
+ "\\s\"\\s$\\s\\\\s/\\s<\\s>\\s|\\s!")))
+
+(ert-deftest rx-category ()
+ (should (equal (rx (category space-for-indent) (category base)
+ (category consonant) (category base-vowel)
+ (category upper-diacritical-mark)
+ (category lower-diacritical-mark)
+ (category tone-mark) (category symbol)
+ (category digit)
+ (category vowel-modifying-diacritical-mark)
+ (category vowel-sign) (category semivowel-lower)
+ (category not-at-end-of-line)
+ (category not-at-beginning-of-line))
+ "\\c \\c.\\c0\\c1\\c2\\c3\\c4\\c5\\c6\\c7\\c8\\c9\\c<\\c>"))
+ (should (equal (rx (category alpha-numeric-two-byte)
+ (category chinese-two-byte) (category greek-two-byte)
+ (category japanese-hiragana-two-byte)
+ (category indian-two-byte)
+ (category japanese-katakana-two-byte)
+ (category strong-left-to-right)
+ (category korean-hangul-two-byte)
+ (category strong-right-to-left)
+ (category cyrillic-two-byte)
+ (category combining-diacritic))
+ "\\cA\\cC\\cG\\cH\\cI\\cK\\cL\\cN\\cR\\cY\\c^"))
+ (should (equal (rx (category ascii) (category arabic) (category chinese)
+ (category ethiopic) (category greek) (category korean)
+ (category indian) (category japanese)
+ (category japanese-katakana) (category latin)
+ (category lao) (category tibetan))
+ "\\ca\\cb\\cc\\ce\\cg\\ch\\ci\\cj\\ck\\cl\\co\\cq"))
+ (should (equal (rx (category japanese-roman) (category thai)
+ (category vietnamese) (category hebrew)
+ (category cyrillic) (category can-break))
+ "\\cr\\ct\\cv\\cw\\cy\\c|"))
+ (should (equal (rx (category ?g) (not (category ?~)))
+ "\\cg\\C~")))
+
+(ert-deftest rx-not ()
+ (should (equal (rx (not word-boundary))
+ "\\B"))
+ (should (equal (rx (not ascii) (not lower-case) (not wordchar))
+ "[^[:ascii:]][^[:lower:]][^[:word:]]"))
+ (should (equal (rx (not (syntax punctuation)) (not (syntax escape)))
+ "\\S.\\S\\"))
+ (should (equal (rx (not (category tone-mark)) (not (category lao)))
+ "\\C4\\Co")))
+
+(ert-deftest rx-group ()
+ (should (equal (rx (group nonl) (submatch "x")
+ (group-n 3 "y") (submatch-n 13 "z") (backref 1))
+ "\\(.\\)\\(x\\)\\(?3:y\\)\\(?13:z\\)\\1"))
+ (should (equal (rx (group) (group-n 2))
+ "\\(\\)\\(?2:\\)")))
+
+(ert-deftest rx-regexp ()
+ (should (equal (rx (regexp "abc") (regex "[de]"))
+ "\\(?:abc\\)[de]"))
+ (let ((x "a*"))
+ (should (equal (rx (regexp x) "b")
+ "\\(?:a*\\)b"))
+ (should (equal (rx "" (regexp x) (eval ""))
+ "a*"))))
+
+(ert-deftest rx-eval ()
+ (should (equal (rx (eval (list 'syntax 'symbol)))
+ "\\s_"))
+ (should (equal (rx "a" (eval (concat)) "b")
+ "ab")))
+
+(ert-deftest rx-literal ()
+ (should (equal (rx (literal (char-to-string 42)) nonl)
+ "\\*."))
+ (let ((x "a+b"))
+ (should (equal (rx (opt (literal (upcase x))))
+ "\\(?:A\\+B\\)?"))))
+
+(ert-deftest rx-to-string ()
+ (should (equal (rx-to-string '(or nonl "\nx"))
+ "\\(?:.\\|\nx\\)"))
+ (should (equal (rx-to-string '(or nonl "\nx") t)
+ ".\\|\nx")))
+
+
+(ert-deftest rx-constituents ()
+ (let ((rx-constituents
+ (append '((beta . gamma)
+ (gamma . "a*b")
+ (delta . ((lambda (form)
+ (regexp-quote (format "<%S>" form)))
+ 1 nil symbolp))
+ (epsilon . delta))
+ rx-constituents)))
+ (should (equal (rx-to-string '(seq (+ beta) nonl gamma) t)
+ "\\(?:a*b\\)+.\\(?:a*b\\)"))
+ (should (equal (rx-to-string '(seq (delta a b c) (* (epsilon d e))) t)
+ "\\(?:<(delta a b c)>\\)\\(?:<(epsilon d e)>\\)*"))))
-(ert-deftest rx-seq ()
- ;; Test zero-argument `seq'.
- (should (equal (rx (seq)) "")))
-
-(defmacro rx-tests--match (regexp string &optional match)
- (macroexp-let2 nil strexp string
- `(ert-info ((format "Matching %S to %S" ',regexp ,strexp))
- (should (string-match ,regexp ,strexp))
- ,@(when match
- `((should (equal (match-string 0 ,strexp) ,match)))))))
-
-(ert-deftest rx-nonstring-expr ()
- (let ((bee "b")
- (vowel "[aeiou]"))
- (rx-tests--match (rx "a" (literal bee) "c") "abc")
- (rx-tests--match (rx "a" (regexp bee) "c") "abc")
- (rx-tests--match (rx "a" (or (regexp bee) "xy") "c") "abc")
- (rx-tests--match (rx "a" (or "xy" (regexp bee)) "c") "abc")
- (should-not (string-match (rx (or (regexp bee) "xy")) ""))
- (rx-tests--match (rx "a" (= 3 (regexp bee)) "c") "abbbc")
- (rx-tests--match (rx "x" (= 3 (regexp vowel)) "z") "xeoez")
- (should-not (string-match (rx "x" (= 3 (regexp vowel)) "z") "xe[]z"))
- (rx-tests--match (rx "x" (= 3 (literal vowel)) "z")
- "x[aeiou][aeiou][aeiou]z")
- (rx-tests--match (rx "x" (repeat 1 (regexp vowel)) "z") "xaz")
- (rx-tests--match (rx "x" (repeat 1 2 (regexp vowel)) "z") "xaz")
- (rx-tests--match (rx "x" (repeat 1 2 (regexp vowel)) "z") "xauz")
- (rx-tests--match (rx "x" (>= 1 (regexp vowel)) "z") "xaiiz")
- (rx-tests--match (rx "x" (** 1 2 (regexp vowel)) "z") "xaiz")
- (rx-tests--match (rx "x" (group (regexp vowel)) "z") "xaz")
- (rx-tests--match (rx "x" (group-n 1 (regexp vowel)) "z") "xaz")
- (rx-tests--match (rx "x" (? (regexp vowel)) "z") "xz")))
-
-(ert-deftest rx-nonstring-expr-non-greedy ()
- "`rx's greediness can't affect runtime regexp parts."
- (let ((ad-min "[ad]*?")
- (ad-max "[ad]*")
- (ad "[ad]"))
- (rx-tests--match (rx "c" (regexp ad-min) "a") "cdaaada" "cda")
- (rx-tests--match (rx "c" (regexp ad-max) "a") "cdaaada" "cdaaada")
- (rx-tests--match (rx "c" (minimal-match (regexp ad-max)) "a") "cdaaada" "cdaaada")
- (rx-tests--match (rx "c" (maximal-match (regexp ad-min)) "a") "cdaaada" "cda")
- (rx-tests--match (rx "c" (minimal-match (0+ (regexp ad))) "a") "cdaaada" "cda")
- (rx-tests--match (rx "c" (maximal-match (0+ (regexp ad))) "a") "cdaaada" "cdaaada")))
-
-(ert-deftest rx-to-string-lisp-forms ()
- (rx-tests--match (rx-to-string '(seq "a" (literal "b") "c")) "abc")
- (rx-tests--match (rx-to-string '(seq "a" (regexp "b") "c")) "abc"))
(provide 'rx-tests)
-;; rx-tests.el ends here.
--
2.20.1 (Apple Git-117)
[-- Attachment #3: 0002-Add-rx-extension-mechanism.patch --]
[-- Type: application/octet-stream, Size: 27059 bytes --]
From e884634efd3cd12e9c2bae733f4e11ababdb18a5 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Mattias=20Engdeg=C3=A5rd?= <mattiase@acm.org>
Date: Mon, 2 Sep 2019 16:07:23 +0200
Subject: [PATCH 2/2] Add rx extension mechanism
Add a built-in set of extension macros: `rx-define', `rx-let' and
`rx-let-eval'.
* lisp/emacs-lisp/rx.el (rx-constituents, rx-to-string): Doc updates.
(rx--builtin-symbols, rx--builtin-names, rx--local-definitions)
(rx--lookup-def, rx--substitute, rx--expand-template)
(rx--make-binding, rx--make-named-binding, rx--extend-local-defs)
(rx-let-eval, rx-let, rx-define): New.
(rx--translate-symbol, rx--translate-form): Use extensions if any.
(rx): Use local definitions.
* test/lisp/emacs-lisp/rx-tests.el (rx-let, rx-define)
(rx-to-string-define, rx-let-define, rx-let-eval): New.
* etc/NEWS (Changes in Specialized Modes and Packages):
* doc/lispref/searching.texi (Rx Notation, Rx Functions, Extending Rx):
Add node about rx extensions.
---
doc/lispref/searching.texi | 157 +++++++++++++++++
etc/NEWS | 4 +
lisp/emacs-lisp/rx.el | 286 ++++++++++++++++++++++++++++---
test/lisp/emacs-lisp/rx-tests.el | 93 ++++++++++
4 files changed, 520 insertions(+), 20 deletions(-)
diff --git a/doc/lispref/searching.texi b/doc/lispref/searching.texi
index 21b1f7b68b..015871fab0 100644
--- a/doc/lispref/searching.texi
+++ b/doc/lispref/searching.texi
@@ -1037,6 +1037,7 @@ Rx Notation
@menu
* Rx Constructs:: Constructs valid in rx forms.
* Rx Functions:: Functions and macros that use rx forms.
+* Extending Rx:: How to define your own rx forms.
@end menu
@node Rx Constructs
@@ -1524,6 +1525,162 @@ Rx Functions
The @code{pcase} macro can use @code{rx} expressions as patterns
directly; @pxref{rx in pcase}.
+
+For mechanisms to add user-defined extensions to the @code{rx}
+notation, @pxref{Extending Rx}.
+
+@node Extending Rx
+@subsubsection Defining new @code{rx} forms
+
+The @code{rx} notation can be extended by defining new symbols and
+parametrised forms in terms of other @code{rx} expressions. This is
+handy for sharing parts between several regexps, and for making
+complex ones easier to build and understand by putting them together
+from smaller pieces.
+
+For example, you could define @code{name} to mean
+@code{(one-or-more letter)}, and @code{(quoted @var{x})} to mean
+@code{(seq ?' @var{x} ?')} for any @var{x}. These forms could then be
+used in @code{rx} expressions like any other: @code{(rx (quoted name))}
+would match a nonempty sequence of letters inside single quotes.
+
+The Lisp macros below provide different ways of binding names to
+definitions. Common to all of them are the following rules:
+
+@itemize
+@item
+Built-in @code{rx} forms, like @code{digit} and @code{group}, cannot
+be redefined.
+
+@item
+The definitions live in a name space of their own, separate from that
+of Lisp variables. There is thus no need to attach a suffix like
+@code{-regexp} to names; they cannot collide with anything else.
+
+@item
+Definitions cannot refer to themselves recursively, directly or
+indirectly. If you find yourself needing this, you want a parser, not
+a regular expression.
+
+@item
+Definitions are only ever expanded in calls to @code{rx} or
+@code{rx-to-string}, not merely by their presence in definition
+macros. This means that the order of definitions doesn't matter, even
+when they refer to each other, and that syntax errors only show up
+when they are used, not when they are defined.
+
+@item
+User-defined forms are allowed wherever arbitrary @code{rx}
+expressions are expected; for example, in the body of a
+@code{zero-or-one} form, but not inside @code{any} or @code{category}
+forms.
+@end itemize
+
+@defmac rx-define name [arglist] rx-form
+Define @var{name} globally in all subsequent calls to @code{rx} and
+@code{rx-to-string}. If @var{arglist} is absent, then @var{name} is
+defined as a plain symbol to be replaced with @var{rx-form}. Example:
+
+@example
+@group
+(rx-define haskell-comment (seq "--" (zero-or-more nonl)))
+(rx haskell-comment)
+ @result{} "--.*"
+@end group
+@end example
+
+If @var{arglist} is present, it must be a list of zero or more
+argument names, and @var{name} is then defined as a parametrised form.
+When used in an @code{rx} expression as @code{(@var{name} @var{arg}@dots{})},
+each @var{arg} will replace the corresponding argument name inside
+@var{rx-form}.
+
+@var{arglist} may end in @code{&rest} and one final argument name,
+denoting a rest parameter. The rest parameter will expand to all
+extra actual argument values not matched by any other parameter in
+@var{arglist}, spliced into @var{rx-form} where it occurs. Example:
+
+@example
+@group
+(rx-define moan (x y &rest r) (seq x (one-or-more y) r "!"))
+(rx (moan "MOO" "A" "MEE" "OW"))
+ @result{} "MOOA+MEEOW!"
+@end group
+@end example
+
+Since the definition is global, it is recommended to give @var{name} a
+package prefix to avoid name clashes with definitions elsewhere, as is
+usual when naming non-local variables and functions.
+@end defmac
+
+@defmac rx-let (bindings@dots{}) body@dots{}
+Make the @code{rx} definitions in @var{bindings} available locally for
+@code{rx} macro invocations in @var{body}, which is then evaluated.
+
+Each element of @var{bindings} is on the form
+@w{@code{(@var{name} [@var{arglist}] @var{rx-form})}}, where the parts
+have the same meaning as in @code{rx-define} above. Example:
+
+@example
+@group
+(rx-let ((comma-separated (item) (seq item (0+ "," item)))
+ (number (1+ digit))
+ (numbers (comma-separated number)))
+ (re-search-forward (rx "(" numbers ")")))
+@end group
+@end example
+
+The definitions are only available during the macro-expansion of
+@var{body}, and are thus not present during execution of compiled
+code.
+
+@code{rx-let} can be used not only inside a function, but also at top
+level to include global variable and function definitions that need
+to share a common set of @code{rx} forms. Since the names are local
+inside @var{body}, there is no need for any package prefixes.
+Example:
+
+@example
+@group
+(rx-let ((phone-number (seq (opt ?+) (1+ (any digit ?-)))))
+ (defun find-next-phone-number ()
+ (re-search-forward (rx phone-number)))
+ (defun phone-number-p (string)
+ (string-match-p (rx bos phone-number eos) string)))
+@end group
+@end example
+
+The scope of the @code{rx-let} bindings is lexical, which means that
+they are not visible outside @var{body} itself, even in functions
+called from @var{body}.
+@end defmac
+
+@defmac rx-let-eval bindings body@dots{}
+Evaluate @var{bindings} to a list of bindings as in @code{rx-let},
+and evaluate @var{body} with those bindings in effect for calls
+to @code{rx-to-string}.
+
+This macro is similar to @code{rx-let}, except that the @var{bindings}
+argument is evaluated (and thus needs to be quoted if it is a list
+literal), and the definitions are substituted at run time, which is
+required for @code{rx-to-string} to work. Example:
+
+@example
+@group
+(rx-let-eval
+ '((ponder (x) (seq "Where have all the " x " gone?")))
+ (looking-at (rx-to-string
+ '(ponder (or "flowers" "young girls"
+ "left socks")))))
+@end group
+@end example
+
+Another difference from @code{rx-let} is that the @var{bindings} are
+dynamically scoped, and thus also available in functions called from
+@var{body}. However, they are not visible inside functions defined in
+@var{body}.
+@end defmac
+
@end ifnottex
@node Regexp Functions
diff --git a/etc/NEWS b/etc/NEWS
index 2db5db3978..b582d38326 100644
--- a/etc/NEWS
+++ b/etc/NEWS
@@ -1688,6 +1688,10 @@ This also works for their aliases: '|' for 'or'; ':', 'and' and
In this case, 'rx' will generate code which produces a regexp string
at run time, instead of a constant string.
+---
+*** New rx extension mechanism: 'rx-define', 'rx-let', 'rx-let-eval'.
+These macros add new forms to the rx notation.
+
** Frames
+++
diff --git a/lisp/emacs-lisp/rx.el b/lisp/emacs-lisp/rx.el
index 8ab32bdb1d..a192ed1ad2 100644
--- a/lisp/emacs-lisp/rx.el
+++ b/lisp/emacs-lisp/rx.el
@@ -97,6 +97,7 @@ rx--char-classes
(defvar rx-constituents nil
"Alist of old-style rx extensions, for compatibility.
+For new code, use `rx-define', `rx-let' or `rx-let-eval'.
Each element is (SYMBOL . DEF).
@@ -113,6 +114,17 @@ rx-constituents
If PRED is non-nil, it is a predicate that all actual arguments must
satisfy.")
+(defvar rx--local-definitions nil
+ "Alist of dynamic local rx definitions.
+Each entry is:
+ (NAME DEF) -- NAME is an rx symbol defined as the rx form DEF.
+ (NAME ARGS DEF) -- NAME is an rx form with arglist ARGS, defined
+ as the rx form DEF (which can contain members of ARGS).")
+
+(defsubst rx--lookup-def (name)
+ (or (cdr (assq name rx--local-definitions))
+ (get name 'rx-definition)))
+
;; TODO: Additions to consider:
;; - A better name for `anything', like `any-char' or `anychar'.
;; - A name for (or), maybe `unmatchable'.
@@ -144,6 +156,12 @@ rx--translate-symbol
((let ((class (cdr (assq sym rx--char-classes))))
(and class (cons (list (concat "[[:" (symbol-name class) ":]]")) t))))
+ ((let ((definition (rx--lookup-def sym)))
+ (and definition
+ (if (cdr definition)
+ (error "Not an `rx' symbol definition: %s" sym)
+ (rx--translate (nth 0 definition))))))
+
;; For compatibility with old rx.
((let ((entry (assq sym rx-constituents)))
(and (progn
@@ -725,6 +743,94 @@ rx--translate-compat-form
(error "The `%s' form did not expand to a string" (car form)))
(cons (list regexp) nil))))
+(defun rx--substitute (bindings form)
+ "Substitute BINDINGS in FORM. BINDINGS is an alist of (NAME . VALUES)
+where VALUES is a list to splice into FORM wherever NAME occurs.
+Return the substitution result wrapped in a list, since a single value
+can expand to any number of values."
+ (cond ((symbolp form)
+ (let ((binding (assq form bindings)))
+ (if binding
+ (cdr binding)
+ (list form))))
+ ((consp form)
+ (if (listp (cdr form))
+ ;; Proper list. We substitute variables even in the head
+ ;; position -- who knows, might be handy one day.
+ (list (mapcan (lambda (x) (copy-sequence
+ (rx--substitute bindings x)))
+ form))
+ ;; Cons pair (presumably an interval).
+ (let ((first (rx--substitute bindings (car form)))
+ (second (rx--substitute bindings (cdr form))))
+ (if (and first (not (cdr first))
+ second (not (cdr second)))
+ (list (cons (car first) (car second)))
+ (error
+ "Cannot substitute a &rest parameter into a dotted pair")))))
+ (t (list form))))
+
+;; FIXME: Consider adding extensions in Lisp macro style, where
+;; arguments are passed unevaluated to code that returns the rx form
+;; to use. Example:
+;;
+;; (rx-let ((radix-digit (radix)
+;; :lisp (list 'any (cons ?0 (+ ?0 (eval radix) -1)))))
+;; (rx (radix-digit (+ 5 3))))
+;; =>
+;; "[0-7]"
+;;
+;; While this would permit more powerful extensions, it's unclear just
+;; how often they would be used in practice. Let's wait until there is
+;; demand for it.
+
+;; FIXME: An alternative binding syntax would be
+;;
+;; (NAME RXs...)
+;; and
+;; ((NAME ARGS...) RXs...)
+;;
+;; which would have two minor advantages: multiple RXs with implicit
+;; `seq' in the definition, and the arglist is no longer an optional
+;; element in the middle of the list. On the other hand, it's less
+;; like traditional lisp arglist constructs (defun, defmacro).
+;; Since it's a Scheme-like syntax, &rest parameters could be done using
+;; dotted lists:
+;; (rx-let (((name arg1 arg2 . rest) ...definition...)) ...)
+
+(defun rx--expand-template (op values arglist template)
+ "Return TEMPLATE with variables in ARGLIST replaced with VALUES."
+ (let ((bindings nil)
+ (value-tail values)
+ (formals arglist))
+ (while formals
+ (pcase (car formals)
+ ('&rest
+ (unless (cdr formals)
+ (error
+ "Expanding rx def `%s': missing &rest parameter name" op))
+ (push (cons (cadr formals) value-tail) bindings)
+ (setq formals nil)
+ (setq value-tail nil))
+ (name
+ (unless value-tail
+ (error
+ "Expanding rx def `%s': too few arguments (got %d, need %s%d)"
+ op (length values)
+ (if (memq '&rest arglist) "at least " "")
+ (- (length arglist) (length (memq '&rest arglist)))))
+ (push (cons name (list (car value-tail))) bindings)
+ (setq value-tail (cdr value-tail))))
+ (setq formals (cdr formals)))
+ (when value-tail
+ (error
+ "Expanding rx def `%s': too many arguments (got %d, need %d)"
+ op (length values) (length arglist)))
+ (let ((subst (rx--substitute bindings template)))
+ (if (and subst (not (cdr subst)))
+ (car subst)
+ (error "Expanding rx def `%s': must result in a single value" op)))))
+
(defun rx--translate-form (form)
"Translate an rx form (list structure). Return (REGEXP . PRECEDENCE)."
(let ((body (cdr form)))
@@ -770,24 +876,29 @@ rx--translate-form
(op
(unless (symbolp op)
(error "Bad rx operator `%S'" op))
+ (let ((definition (rx--lookup-def op)))
+ (if definition
+ (if (cdr definition)
+ (rx--translate
+ (rx--expand-template
+ op body (nth 0 definition) (nth 1 definition)))
+ (error "Not an `rx' form definition: %s" op))
+
+ ;; For compatibility with old rx.
+ (let ((entry (assq op rx-constituents)))
+ (if (progn
+ (while (and entry (not (consp (cdr entry))))
+ (setq entry
+ (if (symbolp (cdr entry))
+ ;; Alias for another entry.
+ (assq (cdr entry) rx-constituents)
+ ;; Wrong type, try further down the list.
+ (assq (car entry)
+ (cdr (memq entry rx-constituents))))))
+ entry)
+ (rx--translate-compat-form (cdr entry) form)
+ (error "Unknown rx form `%s'" op)))))))))
- ;; For compatibility with old rx.
- (let ((entry (assq op rx-constituents)))
- (if (progn
- (while (and entry (not (consp (cdr entry))))
- (setq entry
- (if (symbolp (cdr entry))
- ;; Alias for another entry.
- (assq (cdr entry) rx-constituents)
- ;; Wrong type, try further down the list.
- (assq (car entry)
- (cdr (memq entry rx-constituents))))))
- entry)
- (rx--translate-compat-form (cdr entry) form)
- (error "Unknown rx form `%s'" op)))))))
-
-;; Defined here rather than in re-builder to lower the odds that it
-;; will be kept in sync with changes.
(defconst rx--builtin-forms
'(seq sequence : and or | any in char not-char not
repeat = >= **
@@ -799,7 +910,21 @@ rx--builtin-forms
group submatch group-n submatch-n backref
syntax not-syntax category
literal eval regexp regex)
- "List of built-in rx forms. For use in re-builder only.")
+ "List of built-in rx function-like symbols.")
+
+(defconst rx--builtin-symbols
+ (append '(nonl not-newline any anything
+ bol eol line-start line-end
+ bos eos string-start string-end
+ bow eow word-start word-end
+ symbol-start symbol-end
+ point word-boundary not-word-boundary not-wordchar)
+ (mapcar #'car rx--char-classes))
+ "List of built-in rx variable-like symbols.")
+
+(defconst rx--builtin-names
+ (append rx--builtin-forms rx--builtin-symbols)
+ "List of built-in rx names. These cannot be redefined by the user.")
(defun rx--translate (item)
"Translate the rx-expression ITEM. Return (REGEXP . PRECEDENCE)."
@@ -823,7 +948,9 @@ rx-to-string
The arguments to `literal' and `regexp' forms inside FORM must be
constant strings.
If NO-GROUP is non-nil, don't bracket the result in a non-capturing
-group."
+group.
+
+For extending the `rx' notation in FORM, use `rx-define' or `rx-let-eval'."
(let* ((item (rx--translate form))
(exprs (if no-group
(car item)
@@ -952,14 +1079,133 @@ rx
(regexp EXPR) Match the string regexp from evaluating EXPR at run time.
(eval EXPR) Match the rx sexp from evaluating EXPR at compile time.
+Additional constructs can be defined using `rx-define' and `rx-let',
+which see.
+
\(fn REGEXPS...)"
- (rx--to-expr (cons 'seq regexps)))
+ ;; Retrieve local definitions from the macroexpansion environment.
+ ;; (It's unclear whether the previous value of `rx--local-definitions'
+ ;; should be included, and if so, in which order.)
+ (let ((rx--local-definitions
+ (cdr (assq :rx-locals macroexpand-all-environment))))
+ (rx--to-expr (cons 'seq regexps))))
+
+(defun rx--make-binding (name tail)
+ "Make a definitions entry out of TAIL.
+TAIL is on the form ([ARGLIST] DEFINITION)."
+ (unless (symbolp name)
+ (error "Bad `rx' definition name: %S" name))
+ ;; FIXME: Consider using a hash table or symbol property, for speed.
+ (when (memq name rx--builtin-names)
+ (error "Cannot redefine built-in rx name `%s'" name))
+ (pcase tail
+ (`(,def)
+ (list def))
+ (`(,args ,def)
+ (unless (and (listp args) (rx--every #'symbolp args))
+ (error "Bad argument list for `rx' definition %s: %S" name args))
+ (list args def))
+ (_ (error "Bad `rx' definition of %s: %S" name tail))))
+
+(defun rx--make-named-binding (bindspec)
+ "Make a definitions entry out of BINDSPEC.
+BINDSPEC is on the form (NAME [ARGLIST] DEFINITION)."
+ (unless (consp bindspec)
+ (error "Bad `rx-let' binding: %S" bindspec))
+ (cons (car bindspec)
+ (rx--make-binding (car bindspec) (cdr bindspec))))
+
+(defun rx--extend-local-defs (bindspecs)
+ (append (mapcar #'rx--make-named-binding bindspecs)
+ rx--local-definitions))
+
+;;;###autoload
+(defmacro rx-let-eval (bindings &rest body)
+ "Evaluate BODY with local BINDINGS for `rx-to-string'.
+BINDINGS, after evaluation, is a list of definitions each on the form
+(NAME [(ARGS...)] RX), in effect for calls to `rx-to-string'
+in BODY.
+
+For bindings without an ARGS list, NAME is defined as an alias
+for the `rx' expression RX. Where ARGS is supplied, NAME is
+defined as an `rx' form with ARGS as argument list. The
+parameters are bound from the values in the (NAME ...) form and
+are substituted in RX. ARGS can contain `&rest' parameters,
+whose values are spliced into RX where the parameter name occurs.
+
+Any previous definitions with the same names are shadowed during
+the expansion of BODY only.
+For extensions when using the `rx' macro, use `rx-let'.
+To make global rx extensions, use `rx-define'.
+For more details, see Info node `(elisp) Extending Rx'.
+
+\(fn BINDINGS BODY...)"
+ (declare (indent 1) (debug (form body)))
+ ;; FIXME: this way, `rx--extend-local-defs' may need to be autoloaded.
+ `(let ((rx--local-definitions (rx--extend-local-defs ,bindings)))
+ ,@body))
+;;;###autoload
+(defmacro rx-let (bindings &rest body)
+ "Evaluate BODY with local BINDINGS for `rx'.
+BINDINGS is an unevaluated list of bindings each on the form
+(NAME [(ARGS...)] RX).
+They are bound lexically and are available in `rx' expressions in
+BODY only.
+
+For bindings without an ARGS list, NAME is defined as an alias
+for the `rx' expression RX. Where ARGS is supplied, NAME is
+defined as an `rx' form with ARGS as argument list. The
+parameters are bound from the values in the (NAME ...) form and
+are substituted in RX. ARGS can contain `&rest' parameters,
+whose values are spliced into RX where the parameter name occurs.
+
+Any previous definitions with the same names are shadowed during
+the expansion of BODY only.
+For local extensions to `rx-to-string', use `rx-let-eval'.
+To make global rx extensions, use `rx-define'.
+For more details, see Info node `(elisp) Extending Rx'.
+
+\(fn BINDINGS BODY...)"
+ (declare (indent 1) (debug (sexp body)))
+ (let ((prev-locals (cdr (assq :rx-locals macroexpand-all-environment)))
+ (new-locals (mapcar #'rx--make-named-binding bindings)))
+ (macroexpand-all (cons 'progn body)
+ (cons (cons :rx-locals (append new-locals prev-locals))
+ macroexpand-all-environment))))
+
+;;;###autoload
+(defmacro rx-define (name &rest definition)
+ "Define NAME as a global `rx' definition.
+If the ARGS list is omitted, define NAME as an alias for the `rx'
+expression RX.
+
+If the ARGS list is supplied, define NAME as an `rx' form with
+ARGS as argument list. The parameters are bound from the values
+in the (NAME ...) form and are substituted in RX.
+ARGS can contain `&rest' parameters, whose values are spliced
+into RX where the parameter name occurs.
+
+Any previous global definition of NAME is overwritten with the new one.
+To make local rx extensions, use `rx-let' for `rx',
+`rx-let-eval' for `rx-to-string'.
+For more details, see Info node `(elisp) Extending Rx'.
+
+\(fn NAME [(ARGS...)] RX)"
+ (declare (indent 1))
+ `(eval-and-compile
+ (put ',name 'rx-definition ',(rx--make-binding name definition))
+ ',name))
;; During `rx--pcase-transform', list of defined variables in right-to-left
;; order.
(defvar rx--pcase-vars)
+;; FIXME: The rewriting strategy for pcase works so-so with extensions;
+;; definitions cannot expand to `let' or named `backref'. If this ever
+;; becomes a problem, we can handle those forms in the ordinary parser,
+;; using a dynamic variable for activating the augmented forms.
+
(defun rx--pcase-transform (rx)
"Transform RX, an rx-expression augmented with `let' and named `backref',
into a plain rx-expression, collecting names into `rx--pcase-vars'."
diff --git a/test/lisp/emacs-lisp/rx-tests.el b/test/lisp/emacs-lisp/rx-tests.el
index 56c96e4c44..02b61d9477 100644
--- a/test/lisp/emacs-lisp/rx-tests.el
+++ b/test/lisp/emacs-lisp/rx-tests.el
@@ -298,6 +298,99 @@
(should (equal (rx-to-string '(or nonl "\nx") t)
".\\|\nx")))
+(ert-deftest rx-let ()
+ (rx-let ((beta gamma)
+ (gamma delta)
+ (delta (+ digit))
+ (epsilon (or gamma nonl)))
+ (should (equal (rx bol delta epsilon)
+ "^[[:digit:]]+\\(?:[[:digit:]]+\\|.\\)")))
+ (rx-let ((p () point)
+ (separated (x sep) (seq x (* sep x)))
+ (comma-separated (x) (separated x ","))
+ (semi-separated (x) (separated x ";"))
+ (matrix (v) (semi-separated (comma-separated v))))
+ (should (equal (rx (p) (matrix (+ "a")) eos)
+ "\\=a+\\(?:,a+\\)*\\(?:;a+\\(?:,a+\\)*\\)*\\'")))
+ (rx-let ((b bol)
+ (z "B")
+ (three (x) (= 3 x)))
+ (rx-let ((two (x) (seq x x))
+ (z "A")
+ (e eol))
+ (should (equal (rx b (two (three z)) e)
+ "^A\\{3\\}A\\{3\\}$"))))
+ (rx-let ((f (a b &rest r) (seq "<" a ";" b ":" r ">")))
+ (should (equal (rx bol (f ?x ?y) ?! (f ?u ?v ?w) ?! (f ?k ?l ?m ?n) eol)
+ "^<x;y:>!<u;v:w>!<k;l:mn>$")))
+
+ ;; Rest parameters are expanded by splicing.
+ (rx-let ((f (&rest r) (or bol r eol)))
+ (should (equal (rx (f "ab" nonl))
+ "^\\|ab\\|.\\|$")))
+
+ ;; Substitution is done in number positions.
+ (rx-let ((stars (n) (= n ?*)))
+ (should (equal (rx (stars 4))
+ "\\*\\{4\\}")))
+
+ ;; Substitution is done inside dotted pairs.
+ (rx-let ((f (x y z) (any x (y . z))))
+ (should (equal (rx (f ?* ?a ?t))
+ "[*a-t]")))
+
+ ;; Substitution is done in the head position of forms.
+ (rx-let ((f (x) (x "a")))
+ (should (equal (rx (f +))
+ "a+"))))
+
+(ert-deftest rx-define ()
+ (rx-define rx--a (seq "x" (opt "y")))
+ (should (equal (rx bol rx--a eol)
+ "^xy?$"))
+ (rx-define rx--c (lb rb &rest stuff) (seq lb stuff rb))
+ (should (equal (rx bol (rx--c "<" ">" rx--a nonl) eol)
+ "^<xy?.>$"))
+ (rx-define rx--b (* rx--a))
+ (should (equal (rx rx--b)
+ "\\(?:xy?\\)*"))
+ (rx-define rx--a "z")
+ (should (equal (rx rx--b)
+ "z*")))
+
+(ert-deftest rx-to-string-define ()
+ "Check that `rx-to-string' uses definitions made by `rx-define'."
+ (rx-define rx--d "Q")
+ (should (equal (rx-to-string '(seq bol rx--d) t)
+ "^Q")))
+
+(ert-deftest rx-let-define ()
+ "Test interaction between `rx-let' and `rx-define'."
+ (rx-define rx--e "one")
+ (rx-define rx--f "eins")
+ (rx-let ((rx--e "two"))
+ (should (equal (rx rx--e nonl rx--f) "two.eins"))
+ (rx-define rx--e "three")
+ (should (equal (rx rx--e) "two"))
+ (rx-define rx--f "zwei")
+ (should (equal (rx rx--f) "zwei")))
+ (should (equal (rx rx--e nonl rx--f) "three.zwei")))
+
+(ert-deftest rx-let-eval ()
+ (rx-let-eval '((a (* digit))
+ (f (x &rest r) (seq x nonl r)))
+ (should (equal (rx-to-string '(seq a (f bow a ?b)) t)
+ "[[:digit:]]*\\<.[[:digit:]]*b"))))
+
+(ert-deftest rx-redefine-builtin ()
+ (should-error (rx-define sequence () "x"))
+ (should-error (rx-define sequence "x"))
+ (should-error (rx-define nonl () "x"))
+ (should-error (rx-define nonl "x"))
+ (should-error (rx-let ((punctuation () "x")) nil))
+ (should-error (rx-let ((punctuation "x")) nil))
+ (should-error (rx-let-eval '((not-char () "x")) nil))
+ (should-error (rx-let-eval '((not-char "x")) nil)))
(ert-deftest rx-constituents ()
(let ((rx-constituents
--
2.20.1 (Apple Git-117)
^ permalink raw reply related [flat|nested] 5+ messages in thread* bug#37440: [PATCH] New rx implementation with extension constructs
2019-09-17 12:49 bug#37440: [PATCH] New rx implementation with extension constructs Mattias Engdegård
@ 2019-09-17 17:47 ` Paul Eggert
2019-09-24 17:55 ` Paul Eggert
0 siblings, 1 reply; 5+ messages in thread
From: Paul Eggert @ 2019-09-17 17:47 UTC (permalink / raw)
To: Mattias Engdegård; +Cc: 37440
I like the rx proposal in <https://bugs.gnu.org/37440>. Let's install it into
master if no significant problems turn up after a few days of review. Thanks for
bird-dogging it.
^ permalink raw reply [flat|nested] 5+ messages in thread
* bug#37440: [PATCH] New rx implementation with extension constructs
2019-09-17 17:47 ` Paul Eggert
@ 2019-09-24 17:55 ` Paul Eggert
2019-09-25 12:33 ` Mattias Engdegård
0 siblings, 1 reply; 5+ messages in thread
From: Paul Eggert @ 2019-09-24 17:55 UTC (permalink / raw)
To: Mattias Engdegård; +Cc: 37440
[-- Attachment #1: Type: text/plain, Size: 172 bytes --]
I tried the proposed patches with current Emacs master on Fedora 30
x86-64 and got a test failure as shown in the attached file. Could you
please look into that? Thanks.
[-- Attachment #2: rx-tests.log --]
[-- Type: text/x-log, Size: 3501 bytes --]
Running 25 tests (2019-09-24 10:51:06-0700, selector `(not (or (tag :expensive-test) (tag :unstable)))')
passed 1/25 rx-any (0.000164 sec)
passed 2/25 rx-atoms (0.000106 sec)
passed 3/25 rx-category (0.000088 sec)
passed 4/25 rx-char-any (0.000077 sec)
passed 5/25 rx-char-any-range-nl (0.000078 sec)
Test rx-char-any-raw-byte backtrace:
signal(ert-test-failed (((should (equal (rx (any "\326A\333B")) (str
ert-fail(((should (equal (rx (any "\326A\333B")) (string-to-multibyt
#f(compiled-function () #<bytecode 0x631e5d>)()
ert--run-test-internal(#s(ert--test-execution-info :test #s(ert-test
ert-run-test(#s(ert-test :name rx-char-any-raw-byte :documentation "
ert-run-or-rerun-test(#s(ert--stats :selector (not ...) :tests [...
ert-run-tests((not (or (tag :expensive-test) (tag :unstable))) #f(co
ert-run-tests-batch((not (or (tag :expensive-test) (tag :unstable)))
ert-run-tests-batch-and-exit((not (or (tag :expensive-test) (tag :un
eval((ert-run-tests-batch-and-exit '(not (or (tag :expensive-test) (
command-line-1(("-L" ":." "-l" "ert" "-l" "lisp/emacs-lisp/rx-tests"
command-line()
normal-top-level()
Test rx-char-any-raw-byte condition:
(ert-test-failed
((should
(equal
(rx ...)
(string-to-multibyte "[AB\326\333]")))
:form
(equal "[AB\326\333]" "[AB\326\333]")
:value nil :explanation
(array-elt 3
(different-atoms
(214 "#xd6" "?Ö")
(4194262 "#x3fffd6" "?\326")))))
FAILED 6/25 rx-char-any-raw-byte (0.000191 sec)
passed 7/25 rx-constituents (0.000136 sec)
passed 8/25 rx-define (0.000081 sec)
passed 9/25 rx-eval (0.000076 sec)
passed 10/25 rx-group (0.000075 sec)
passed 11/25 rx-kleene (0.000084 sec)
passed 12/25 rx-let (0.000109 sec)
passed 13/25 rx-let-define (0.000081 sec)
passed 14/25 rx-let-eval (0.000102 sec)
passed 15/25 rx-literal (0.000083 sec)
passed 16/25 rx-not (0.000084 sec)
passed 17/25 rx-or (0.000084 sec)
passed 18/25 rx-pcase (0.000108 sec)
passed 19/25 rx-redefine-builtin (0.000129 sec)
passed 20/25 rx-regexp (0.000087 sec)
passed 21/25 rx-repeat (0.000090 sec)
passed 22/25 rx-seq (0.000095 sec)
passed 23/25 rx-syntax (0.000083 sec)
passed 24/25 rx-to-string (0.000091 sec)
Test rx-to-string-define backtrace:
signal(error ("Unknown rx symbol `rx--d'"))
apply(signal (error ("Unknown rx symbol `rx--d'")))
#f(compiled-function () #<bytecode 0x637951>)()
ert--run-test-internal(#s(ert--test-execution-info :test #s(ert-test
ert-run-test(#s(ert-test :name rx-to-string-define :documentation "C
ert-run-or-rerun-test(#s(ert--stats :selector ... :tests ... :test-m
ert-run-tests((not (or (tag :expensive-test) (tag :unstable))) #f(co
ert-run-tests-batch((not (or (tag :expensive-test) (tag :unstable)))
ert-run-tests-batch-and-exit((not (or (tag :expensive-test) (tag :un
eval((ert-run-tests-batch-and-exit '(not (or (tag :expensive-test) (
command-line-1(("-L" ":." "-l" "ert" "-l" "lisp/emacs-lisp/rx-tests"
command-line()
normal-top-level()
Test rx-to-string-define condition:
(error "Unknown rx symbol `rx--d'")
FAILED 25/25 rx-to-string-define (0.000149 sec)
Ran 25 tests, 23 results as expected, 2 unexpected (2019-09-24 10:51:06-0700, 0.264977 sec)
2 unexpected results:
FAILED rx-char-any-raw-byte
FAILED rx-to-string-define
^ permalink raw reply [flat|nested] 5+ messages in thread* bug#37440: [PATCH] New rx implementation with extension constructs
2019-09-24 17:55 ` Paul Eggert
@ 2019-09-25 12:33 ` Mattias Engdegård
2019-09-25 21:30 ` Paul Eggert
0 siblings, 1 reply; 5+ messages in thread
From: Mattias Engdegård @ 2019-09-25 12:33 UTC (permalink / raw)
To: Paul Eggert; +Cc: 37440
[-- Attachment #1: Type: text/plain, Size: 1208 bytes --]
24 sep. 2019 kl. 19.55 skrev Paul Eggert <eggert@cs.ucla.edu>:
>
> I tried the proposed patches with current Emacs master on Fedora 30 x86-64 and got a test failure as shown in the attached file.
Thank you! Those failures only occur when running test loaded from a byte-compiled file -- I suppose you used TEST_LOAD_EL=no.
First, the unibyte and multibyte forms of a string like "\326" print the same but aren't equal:
(string-to-multibyte "\326")
=> "\326"
(equal (string-to-multibyte "\326") "\326")
=> nil
This means that if a multibyte string ends up as a constant in byte-compiled code, surprise, it may become a unibyte value when loaded. The test had to be made to work both interpreted and compiled. Fortunately the regexp engine was recently fixed with respect to raw bytes, making its semantics invariant for strings with the same print representation, so this is not a problem with the rx implementation.
The second item of interest was that `rx-define', since it relies on `eval-and-compile', doesn't expand to code when macroexpanded. I don't know if it will be a problem in practice. The test now uses an auxiliary function as work-around.
Updated patches attached.
[-- Attachment #2: 0001-New-rx-implementation.patch --]
[-- Type: application/octet-stream, Size: 93292 bytes --]
From 0eb84f9a8e378e0a1a14065915129edc060d0722 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Mattias=20Engdeg=C3=A5rd?= <mattiase@acm.org>
Date: Sun, 15 Sep 2019 16:11:09 +0200
Subject: [PATCH 1/2] New rx implementation
* lisp/emacs-lisp/rx.el:
* test/lisp/emacs-lisp/rx-tests.el:
* doc/lispref/searching.texi (Rx Constructs):
Rewrite rx for correctness, clarity, and performance. The new
implementation retains full compatibility and has more comprehensive
tests.
* lisp/emacs-lisp/re-builder.el (reb-rx-font-lock-keywords):
Adapt to changes in internal variables in rx.el.
---
doc/lispref/searching.texi | 4 +-
lisp/emacs-lisp/re-builder.el | 9 +-
lisp/emacs-lisp/rx.el | 1809 ++++++++++++++----------------
test/lisp/emacs-lisp/rx-tests.el | 336 ++++--
4 files changed, 1091 insertions(+), 1067 deletions(-)
diff --git a/doc/lispref/searching.texi b/doc/lispref/searching.texi
index 1286b63446..21b1f7b68b 100644
--- a/doc/lispref/searching.texi
+++ b/doc/lispref/searching.texi
@@ -1044,11 +1044,9 @@ Rx Constructs
The various forms in @code{rx} regexps are described below. The
shorthand @var{rx} represents any @code{rx} form, and @var{rx}@dots{}
-means one or more @code{rx} forms. Where the corresponding string
+means zero or more @code{rx} forms. Where the corresponding string
regexp syntax is given, @var{A}, @var{B}, @dots{} are string regexp
subexpressions.
-@c With the new implementation of rx, this can be changed from
-@c 'one or more' to 'zero or more'.
@subsubheading Literals
diff --git a/lisp/emacs-lisp/re-builder.el b/lisp/emacs-lisp/re-builder.el
index 961d26a721..1054f1453b 100644
--- a/lisp/emacs-lisp/re-builder.el
+++ b/lisp/emacs-lisp/re-builder.el
@@ -816,13 +816,12 @@ reb-mark-non-matching-parenthesis
(require 'rx)
(defconst reb-rx-font-lock-keywords
- (let ((constituents (mapcar (lambda (rec)
- (symbol-name (car rec)))
- rx-constituents))
- (syntax (mapcar (lambda (rec) (symbol-name (car rec))) rx-syntax))
+ (let ((constituents (mapcar #'symbol-name rx--builtin-forms))
+ (syntax (mapcar (lambda (rec) (symbol-name (car rec)))
+ rx--syntax-codes))
(categories (mapcar (lambda (rec)
(symbol-name (car rec)))
- rx-categories)))
+ rx--categories)))
`(
(,(concat "(" (regexp-opt (list "rx-to-string") t) "[[:space:]]")
(1 font-lock-function-name-face))
diff --git a/lisp/emacs-lisp/rx.el b/lisp/emacs-lisp/rx.el
index 249529e54e..9b3419e1c8 100644
--- a/lisp/emacs-lisp/rx.el
+++ b/lisp/emacs-lisp/rx.el
@@ -1,11 +1,7 @@
-;;; rx.el --- sexp notation for regular expressions -*- lexical-binding: t -*-
+;;; rx.el --- S-exp notation for regexps --*- lexical-binding: t -*-
;; Copyright (C) 2001-2019 Free Software Foundation, Inc.
-;; Author: Gerd Moellmann <gerd@gnu.org>
-;; Maintainer: emacs-devel@gnu.org
-;; Keywords: strings, regexps, extensions
-
;; This file is part of GNU Emacs.
;; GNU Emacs is free software: you can redistribute it and/or modify
@@ -23,937 +19,824 @@
;;; Commentary:
-;; This is another implementation of sexp-form regular expressions.
-;; It was unfortunately written without being aware of the Sregex
-;; package coming with Emacs, but as things stand, Rx completely
-;; covers all regexp features, which Sregex doesn't, doesn't suffer
-;; from the bugs mentioned in the commentary section of Sregex, and
-;; uses a nicer syntax (IMHO, of course :-).
-
-;; This significantly extended version of the original, is almost
-;; compatible with Sregex. The only incompatibility I (fx) know of is
-;; that the `repeat' form can't have multiple regexp args.
-
-;; Now alternative forms are provided for a degree of compatibility
-;; with Olin Shivers' attempted definitive SRE notation. SRE forms
-;; not catered for include: dsm, uncase, w/case, w/nocase, ,@<exp>,
-;; ,<exp>, (word ...), word+, posix-string, and character class forms.
-;; Some forms are inconsistent with SRE, either for historical reasons
-;; or because of the implementation -- simple translation into Emacs
-;; regexp strings. These include: any, word. Also, case-sensitivity
-;; and greediness are controlled by variables external to the regexp,
-;; and you need to feed the forms to the `posix-' functions to get
-;; SRE's POSIX semantics. There are probably more difficulties.
-
-;; Rx translates a sexp notation for regular expressions into the
-;; usual string notation. The translation can be done at compile-time
-;; by using the `rx' macro. The `regexp' and `literal' forms accept
-;; non-constant expressions, in which case `rx' will translate to a
-;; `concat' expression. Translation can be done fully at run time by
-;; calling function `rx-to-string'. See the documentation of `rx' for
-;; a complete description of the sexp notation.
-;;
-;; Some examples of string regexps and their sexp counterparts:
-;;
-;; "^[a-z]*"
-;; (rx line-start (0+ (in "a-z")))
-;;
-;; "\n[^ \t]"
-;; (rx ?\n (not (in " \t")))
-;;
-;; "\\*\\*\\* EOOH \\*\\*\\*\n"
-;; (rx "*** EOOH ***\n")
-;;
-;; "\\<\\(catch\\|finally\\)\\>[^_]"
-;; (rx word-start (submatch (or "catch" "finally")) word-end
-;; (not (in ?_)))
-;;
-;; "[ \t\n]*:\\($\\|[^:]+\\)"
-;; (rx (* (in " \t\n")) ":"
-;; (submatch (or line-end (+ (not (in ?:))))))
-;;
-;; "^content-transfer-encoding:\\(?:\n?[\t ]\\)*quoted-printable\\(?:\n?[\t ]\\)*"
-;; (rx line-start
-;; "content-transfer-encoding:"
-;; (* (? ?\n) (in " \t"))
-;; "quoted-printable"
-;; (* (? ?\n) (in " \t")))
-;;
-;; (concat "^\\(?:" something-else "\\)")
-;; (rx line-start (regexp something-else))
-;;
-;; (regexp-opt '(STRING1 STRING2 ...))
-;; (rx (or STRING1 STRING2 ...)), or in other words, `or' automatically
-;; calls `regexp-opt' as needed.
-;;
-;; "^;;\\s-*\n\\|^\n"
-;; (rx (or (seq line-start ";;" (0+ space) ?\n)
-;; (seq line-start ?\n)))
+;; This facility allows writing regexps in a sexp-based language
+;; instead of strings. Regexps in the `rx' notation are easier to
+;; read, write and maintain; they can be indented and commented in a
+;; natural way, and are easily composed by program code.
+;; The translation to string regexp is done by a macro and does not
+;; incur any extra processing during run time. Example:
;;
-;; "\\$[I]d: [^ ]+ \\([^ ]+\\) "
-;; (rx "$Id: "
-;; (1+ (not (in " ")))
-;; " "
-;; (submatch (1+ (not (in " "))))
-;; " ")
+;; (rx bos (or (not (any "^"))
+;; (seq "^" (or " *" "["))))
;;
-;; "\\\\\\\\\\[\\w+"
-;; (rx "\\\\[" (1+ word))
-;;
-;; etc.
-
-;;; History:
+;; => "\\`\\(?:[^^]\\|\\^\\(?: \\*\\|\\[\\)\\)"
;;
+;; The notation is much influenced by and retains some compatibility with
+;; Olin Shivers's SRE, with concessions to Emacs regexp peculiarities,
+;; and the older Emacs package Sregex.
;;; Code:
-(require 'cl-lib)
-(require 'cl-extra)
-
-;; FIXME: support macros.
-
-(defvar rx-constituents ;Not `const' because some modes extend it.
- '((and . (rx-and 0 nil))
- (seq . and) ; SRE
- (: . and) ; SRE
- (sequence . and) ; sregex
- (or . (rx-or 0 nil))
- (| . or) ; SRE
- (not-newline . ".")
- (nonl . not-newline) ; SRE
- (anything . (rx-anything 0 nil))
- (any . (rx-any 1 nil rx-check-any)) ; inconsistent with SRE
- (any . ".") ; sregex
- (in . any)
- (char . any) ; sregex
- (not-char . (rx-not-char 1 nil rx-check-any)) ; sregex
- (not . (rx-not 1 1 rx-check-not))
- (repeat . (rx-repeat 2 nil))
- (= . (rx-= 2 nil)) ; SRE
- (>= . (rx->= 2 nil)) ; SRE
- (** . (rx-** 2 nil)) ; SRE
- (submatch . (rx-submatch 1 nil)) ; SRE
- (group . submatch) ; sregex
- (submatch-n . (rx-submatch-n 2 nil))
- (group-n . submatch-n)
- (zero-or-more . (rx-kleene 1 nil))
- (one-or-more . (rx-kleene 1 nil))
- (zero-or-one . (rx-kleene 1 nil))
- (\? . zero-or-one) ; SRE
- (\?? . zero-or-one)
- (* . zero-or-more) ; SRE
- (*? . zero-or-more)
- (0+ . zero-or-more)
- (+ . one-or-more) ; SRE
- (+? . one-or-more)
- (1+ . one-or-more)
- (optional . zero-or-one)
- (opt . zero-or-one) ; sregex
- (minimal-match . (rx-greedy 1 1))
- (maximal-match . (rx-greedy 1 1))
- (backref . (rx-backref 1 1 rx-check-backref))
- (line-start . "^")
- (bol . line-start) ; SRE
- (line-end . "$")
- (eol . line-end) ; SRE
- (string-start . "\\`")
- (bos . string-start) ; SRE
- (bot . string-start) ; sregex
- (string-end . "\\'")
- (eos . string-end) ; SRE
- (eot . string-end) ; sregex
- (buffer-start . "\\`")
- (buffer-end . "\\'")
- (point . "\\=")
- (word-start . "\\<")
- (bow . word-start) ; SRE
- (word-end . "\\>")
- (eow . word-end) ; SRE
- (word-boundary . "\\b")
- (not-word-boundary . "\\B") ; sregex
- (symbol-start . "\\_<")
- (symbol-end . "\\_>")
- (syntax . (rx-syntax 1 1))
- (not-syntax . (rx-not-syntax 1 1)) ; sregex
- (category . (rx-category 1 1 rx-check-category))
- (eval . (rx-eval 1 1))
- (literal . (rx-literal 1 1 stringp))
- (regexp . (rx-regexp 1 1 stringp))
- (regex . regexp) ; sregex
- (digit . "[[:digit:]]")
- (numeric . digit) ; SRE
- (num . digit) ; SRE
- (control . "[[:cntrl:]]") ; SRE
- (cntrl . control) ; SRE
- (hex-digit . "[[:xdigit:]]") ; SRE
- (hex . hex-digit) ; SRE
- (xdigit . hex-digit) ; SRE
- (blank . "[[:blank:]]") ; SRE
- (graphic . "[[:graph:]]") ; SRE
- (graph . graphic) ; SRE
- (printing . "[[:print:]]") ; SRE
- (print . printing) ; SRE
- (alphanumeric . "[[:alnum:]]") ; SRE
- (alnum . alphanumeric) ; SRE
- (letter . "[[:alpha:]]")
- (alphabetic . letter) ; SRE
- (alpha . letter) ; SRE
- (ascii . "[[:ascii:]]") ; SRE
- (nonascii . "[[:nonascii:]]")
- (lower . "[[:lower:]]") ; SRE
- (lower-case . lower) ; SRE
- (punctuation . "[[:punct:]]") ; SRE
- (punct . punctuation) ; SRE
- (space . "[[:space:]]") ; SRE
- (whitespace . space) ; SRE
- (white . space) ; SRE
- (upper . "[[:upper:]]") ; SRE
- (upper-case . upper) ; SRE
- (word . "[[:word:]]") ; inconsistent with SRE
- (wordchar . word) ; sregex
- (not-wordchar . "\\W"))
- "Alist of sexp form regexp constituents.
-Each element of the alist has the form (SYMBOL . DEFN).
-SYMBOL is a valid constituent of sexp regular expressions.
-If DEFN is a string, SYMBOL is translated into DEFN.
-If DEFN is a symbol, use the definition of DEFN, recursively.
-Otherwise, DEFN must be a list (FUNCTION MIN-ARGS MAX-ARGS PREDICATE).
-FUNCTION is used to produce code for SYMBOL. MIN-ARGS and MAX-ARGS
-are the minimum and maximum number of arguments the function-form
-sexp constituent SYMBOL may have in sexp regular expressions.
-MAX-ARGS nil means no limit. PREDICATE, if specified, means that
-all arguments must satisfy PREDICATE.")
-
-
-(defconst rx-syntax
- '((whitespace . ?-)
- (punctuation . ?.)
- (word . ?w)
- (symbol . ?_)
- (open-parenthesis . ?\()
- (close-parenthesis . ?\))
- (expression-prefix . ?\')
- (string-quote . ?\")
- (paired-delimiter . ?$)
- (escape . ?\\)
- (character-quote . ?/)
- (comment-start . ?<)
- (comment-end . ?>)
- (string-delimiter . ?|)
- (comment-delimiter . ?!))
- "Alist mapping Rx syntax symbols to syntax characters.
-Each entry has the form (SYMBOL . CHAR), where SYMBOL is a valid
-symbol in `(syntax SYMBOL)', and CHAR is the syntax character
-corresponding to SYMBOL, as it would be used with \\s or \\S in
-regular expressions.")
-
-
-(defconst rx-categories
- '((space-for-indent . ?\s)
- (base . ?.)
- (consonant . ?0)
- (base-vowel . ?1)
- (upper-diacritical-mark . ?2)
- (lower-diacritical-mark . ?3)
- (tone-mark . ?4)
- (symbol . ?5)
- (digit . ?6)
- (vowel-modifying-diacritical-mark . ?7)
- (vowel-sign . ?8)
- (semivowel-lower . ?9)
- (not-at-end-of-line . ?<)
- (not-at-beginning-of-line . ?>)
- (alpha-numeric-two-byte . ?A)
- (chinese-two-byte . ?C)
- (chinse-two-byte . ?C) ;; A typo in Emacs 21.1-24.3.
- (greek-two-byte . ?G)
- (japanese-hiragana-two-byte . ?H)
- (indian-two-byte . ?I)
- (japanese-katakana-two-byte . ?K)
- (strong-left-to-right . ?L)
- (korean-hangul-two-byte . ?N)
- (strong-right-to-left . ?R)
- (cyrillic-two-byte . ?Y)
- (combining-diacritic . ?^)
- (ascii . ?a)
- (arabic . ?b)
- (chinese . ?c)
- (ethiopic . ?e)
- (greek . ?g)
- (korean . ?h)
- (indian . ?i)
- (japanese . ?j)
- (japanese-katakana . ?k)
- (latin . ?l)
- (lao . ?o)
- (tibetan . ?q)
- (japanese-roman . ?r)
- (thai . ?t)
- (vietnamese . ?v)
- (hebrew . ?w)
- (cyrillic . ?y)
- (can-break . ?|))
- "Alist mapping symbols to category characters.
-Each entry has the form (SYMBOL . CHAR), where SYMBOL is a valid
-symbol in `(category SYMBOL)', and CHAR is the category character
-corresponding to SYMBOL, as it would be used with `\\c' or `\\C' in
-regular expression strings.")
-
-
-(defvar rx-greedy-flag t
- "Non-nil means produce greedy regular expressions for `zero-or-one',
-`zero-or-more', and `one-or-more'. Dynamically bound.")
-
-(defvar rx--compile-to-lisp nil
- "Nil means return a regexp as a string.
-Non-nil means we may return a lisp form which produces a
-string (used for `rx' macro).")
-
-(defun rx-info (op head)
- "Return parsing/code generation info for OP.
-If OP is the space character ASCII 32, return info for the symbol `?'.
-If OP is the character `?', return info for the symbol `??'.
-See also `rx-constituents'.
-If HEAD is non-nil, then OP is the head of a sexp, otherwise it's
-a standalone symbol."
- (cond ((eq op ? ) (setq op '\?))
- ((eq op ??) (setq op '\??)))
- (let (old-op)
- (while (and (not (null op)) (symbolp op))
- (setq old-op op)
- (setq op (cdr (assq op rx-constituents)))
- (when (if head (stringp op) (consp op))
- ;; We found something but of the wrong kind. Let's look for an
- ;; alternate definition for the other case.
- (let ((new-op
- (cdr (assq old-op (cdr (memq (assq old-op rx-constituents)
- rx-constituents))))))
- (if (and new-op (not (if head (stringp new-op) (consp new-op))))
- (setq op new-op))))))
- op)
-
-
-(defun rx-check (form)
- "Check FORM according to its car's parsing info."
- (unless (listp form)
- (error "rx `%s' needs argument(s)" form))
- (let* ((rx (rx-info (car form) 'head))
- (nargs (1- (length form)))
- (min-args (nth 1 rx))
- (max-args (nth 2 rx))
- (type-pred (nth 3 rx)))
- (when (and (not (null min-args))
- (< nargs min-args))
- (error "rx form `%s' requires at least %d args"
- (car form) min-args))
- (when (and (not (null max-args))
- (> nargs max-args))
- (error "rx form `%s' accepts at most %d args"
- (car form) max-args))
- (when type-pred
- (dolist (sub-form (cdr form))
- (unless (funcall type-pred sub-form)
- (error "rx form `%s' requires args satisfying `%s'"
- (car form) type-pred))))))
-
-
-(defun rx-group-if (regexp group)
- "Put shy groups around REGEXP if seemingly necessary when GROUP
-is non-nil."
+;; The `rx--translate...' functions below return (REGEXP . PRECEDENCE),
+;; where REGEXP is a list of string expressions that will be
+;; concatenated into a regexp, and PRECEDENCE is one of
+;;
+;; t -- can be used as argument to postfix operators (eg. "a")
+;; seq -- can be concatenated in sequence with other seq or higher (eg. "ab")
+;; lseq -- can be concatenated to the left of rseq or higher (eg. "^a")
+;; rseq -- can be concatenated to the right of lseq or higher (eg. "a$")
+;; nil -- can only be used in alternatives (eg. "a\\|b")
+;;
+;; They form a lattice:
+;;
+;; t highest precedence
+;; |
+;; seq
+;; / \
+;; lseq rseq
+;; \ /
+;; nil lowest precedence
+
+
+(defconst rx--char-classes
+ '((digit . digit)
+ (numeric . digit)
+ (num . digit)
+ (control . cntrl)
+ (cntrl . cntrl)
+ (hex-digit . xdigit)
+ (hex . xdigit)
+ (xdigit . xdigit)
+ (blank . blank)
+ (graphic . graph)
+ (graph . graph)
+ (printing . print)
+ (print . print)
+ (alphanumeric . alnum)
+ (alnum . alnum)
+ (letter . alpha)
+ (alphabetic . alpha)
+ (alpha . alpha)
+ (ascii . ascii)
+ (nonascii . nonascii)
+ (lower . lower)
+ (lower-case . lower)
+ (punctuation . punct)
+ (punct . punct)
+ (space . space)
+ (whitespace . space)
+ (white . space)
+ (upper . upper)
+ (upper-case . upper)
+ (word . word)
+ (wordchar . word)
+ (unibyte . unibyte)
+ (multibyte . multibyte))
+ "Alist mapping rx symbols to character classes.
+Most of the names are from SRE.")
+
+(defvar rx-constituents nil
+ "Alist of old-style rx extensions, for compatibility.
+
+Each element is (SYMBOL . DEF).
+
+If DEF is a symbol, then SYMBOL is an alias of DEF.
+
+If DEF is a string, then SYMBOL is a plain rx symbol defined as the
+ regexp string DEF.
+
+If DEF is a list on the form (FUN MIN-ARGS MAX-ARGS PRED), then
+ SYMBOL is an rx form with at least MIN-ARGS and at most
+ MAX-ARGS arguments. If MAX-ARGS is nil, then there is no upper limit.
+ FUN is a function taking the entire rx form as single argument
+ and returning the translated regexp string.
+ If PRED is non-nil, it is a predicate that all actual arguments must
+ satisfy.")
+
+;; TODO: Additions to consider:
+;; - A better name for `anything', like `any-char' or `anychar'.
+;; - A name for (or), maybe `unmatchable'.
+;; - A construct like `or' but without the match order guarantee,
+;; maybe `unordered-or'. Useful for composition or generation of
+;; alternatives; permits more effective use of regexp-opt.
+
+(defun rx--translate-symbol (sym)
+ "Translate an rx symbol. Return (REGEXP . PRECEDENCE)."
+ (pcase sym
+ ;; Use `list' instead of a quoted list to wrap the strings here,
+ ;; since the return value may be mutated.
+ ((or 'nonl 'not-newline 'any) (cons (list ".") t))
+ ('anything (rx--translate-form '(or nonl "\n")))
+ ((or 'bol 'line-start) (cons (list "^") 'lseq))
+ ((or 'eol 'line-end) (cons (list "$") 'rseq))
+ ((or 'bos 'string-start 'bot 'buffer-start) (cons (list "\\`") t))
+ ((or 'eos 'string-end 'eot 'buffer-end) (cons (list "\\'") t))
+ ('point (cons (list "\\=") t))
+ ((or 'bow 'word-start) (cons (list "\\<") t))
+ ((or 'eow 'word-end) (cons (list "\\>") t))
+ ('word-boundary (cons (list "\\b") t))
+ ('not-word-boundary (cons (list "\\B") t))
+ ('symbol-start (cons (list "\\_<") t))
+ ('symbol-end (cons (list "\\_>") t))
+ ('not-wordchar (cons (list "\\W") t))
+ (_
+ (cond
+ ((let ((class (cdr (assq sym rx--char-classes))))
+ (and class (cons (list (concat "[[:" (symbol-name class) ":]]")) t))))
+
+ ;; For compatibility with old rx.
+ ((let ((entry (assq sym rx-constituents)))
+ (and (progn
+ (while (and entry (not (stringp (cdr entry))))
+ (setq entry
+ (if (symbolp (cdr entry))
+ ;; Alias for another entry.
+ (assq (cdr entry) rx-constituents)
+ ;; Wrong type, try further down the list.
+ (assq (car entry)
+ (cdr (memq entry rx-constituents))))))
+ entry)
+ (cons (list (cdr entry)) nil))))
+ (t (error "Unknown rx symbol `%s'" sym))))))
+
+(defun rx--enclose (left-str rexp right-str)
+ "Bracket REXP by LEFT-STR and RIGHT-STR."
+ (append (list left-str) rexp (list right-str)))
+
+(defun rx--bracket (rexp)
+ (rx--enclose "\\(?:" rexp "\\)"))
+
+(defun rx--sequence (left right)
+ "Return the sequence (concatenation) of two translated items,
+each on the form (REGEXP . PRECEDENCE), returning (REGEXP . PRECEDENCE)."
+ ;; Concatenation rules:
+ ;; seq ++ seq -> seq
+ ;; lseq ++ seq -> lseq
+ ;; seq ++ rseq -> rseq
+ ;; lseq ++ rseq -> nil
+ (cond ((not (car left)) right)
+ ((not (car right)) left)
+ (t
+ (let ((l (if (memq (cdr left) '(nil rseq))
+ (cons (rx--bracket (car left)) t)
+ left))
+ (r (if (memq (cdr right) '(nil lseq))
+ (cons (rx--bracket (car right)) t)
+ right)))
+ (cons (append (car l) (car r))
+ (if (eq (cdr l) 'lseq)
+ (if (eq (cdr r) 'rseq)
+ nil ; lseq ++ rseq
+ 'lseq) ; lseq ++ seq
+ (if (eq (cdr r) 'rseq)
+ 'rseq ; seq ++ rseq
+ 'seq))))))) ; seq ++ seq
+
+(defun rx--translate-seq (body)
+ "Translate a sequence of one or more rx items. Return (REGEXP . PRECEDENCE)."
+ (if body
+ (let* ((items (mapcar #'rx--translate body))
+ (result (car items)))
+ (dolist (item (cdr items))
+ (setq result (rx--sequence result item)))
+ result)
+ (cons nil 'seq)))
+
+(defun rx--empty ()
+ "Regexp that never matches anything."
+ (cons (list regexp-unmatchable) 'seq))
+
+;; `cl-every' replacement to avoid bootstrapping problems.
+(defun rx--every (pred list)
+ "Whether PRED is true for every element of LIST."
+ (while (and list (funcall pred (car list)))
+ (setq list (cdr list)))
+ (null list))
+
+(defun rx--translate-or (body)
+ "Translate an or-pattern of one of more rx items.
+Return (REGEXP . PRECEDENCE)."
+ ;; FIXME: Possible improvements:
+ ;;
+ ;; - Turn single characters to strings: (or ?a ?b) -> (or "a" "b"),
+ ;; so that they can be candidates for regexp-opt.
+ ;;
+ ;; - Translate compile-time strings (`eval' forms), again for regexp-opt.
+ ;;
+ ;; - Flatten sub-patterns first: (or (or A B) (or C D)) -> (or A B C D)
+ ;; in order to improve effectiveness of regexp-opt.
+ ;; This would also help composability.
+ ;;
+ ;; - Use associativity to run regexp-opt on contiguous subsets of arguments
+ ;; if not all of them are strings. Example:
+ ;; (or (+ digit) "CHARLIE" "CHAN" (+ blank))
+ ;; -> (or (+ digit) (or "CHARLIE" "CHAN") (+ blank))
+ ;;
+ ;; - Fuse patterns into a single character alternative if they fit.
+ ;; regexp-opt will do that if all are strings, but we want to do that for:
+ ;; * symbols that expand to classes: space, alpha, ...
+ ;; * character alternatives: (any ...)
+ ;; * (syntax S), for some S (whitespace, word)
+ ;; so that (or "@" "%" digit (any "A-Z" space) (syntax word))
+ ;; -> (any "@" "%" digit "A-Z" space word)
+ ;; -> "[A-Z@%[:digit:][:space:][:word:]]"
+ ;;
+ ;; Problem: If a subpattern is carefully written to to be
+ ;; optimisable by regexp-opt, how do we prevent the transforms
+ ;; above from destroying that property?
+ ;; Example: (or "a" (or "abc" "abd" "abe"))
(cond
- ;; for some repetition
- ((eq group '*) (if (rx-atomic-p regexp) (setq group nil)))
- ;; for concatenation
- ((eq group ':)
- (if (rx-atomic-p
- (if (and (stringp regexp)
- (string-match
- "\\(?:[?*+]\\??\\|\\\\{[0-9]*,?[0-9]*\\\\}\\)\\'" regexp))
- (substring regexp 0 (match-beginning 0))
- regexp))
- (setq group nil)))
- ;; for OR
- ((eq group '|) (setq group nil))
- ;; do anyway
- ((eq group t))
- ((rx-atomic-p regexp t) (setq group nil)))
- (cond ((and group (stringp regexp))
- (concat "\\(?:" regexp "\\)"))
- (group `("\\(?:" ,@regexp "\\)"))
- (t regexp)))
-
-
-(defvar rx-parent)
-;; dynamically bound in some functions.
-
-
-(defun rx-and (form)
- "Parse and produce code from FORM.
-FORM is of the form `(and FORM1 ...)'."
- (rx-check form)
- (rx-group-if
- (rx--subforms (cdr form) ':)
- (and (memq rx-parent '(* t)) rx-parent)))
-
-
-(defun rx-or (form)
- "Parse and produce code from FORM, which is `(or FORM1 ...)'."
- (rx-check form)
- (rx-group-if
- (cond
- ((null (cdr form)) regexp-unmatchable)
- ((cl-every #'stringp (cdr form))
- (regexp-opt (cdr form) nil t))
- (t (rx--subforms (cdr form) '| "\\|")))
- (and (memq rx-parent '(: * t)) rx-parent)))
-
-
-(defun rx-anything (form)
- "Match any character."
- (if (consp form)
- (error "rx `anything' syntax error: %s" form))
- (rx-or (list 'or 'not-newline ?\n)))
-
-
-(defun rx-any-delete-from-range (char ranges)
- "Delete by side effect character CHAR from RANGES.
-Only both edges of each range is checked."
- (let (m)
- (cond
- ((memq char ranges) (setq ranges (delq char ranges)))
- ((setq m (assq char ranges))
- (if (eq (1+ char) (cdr m))
- (setcar (memq m ranges) (1+ char))
- (setcar m (1+ char))))
- ((setq m (rassq char ranges))
- (if (eq (1- char) (car m))
- (setcar (memq m ranges) (1- char))
- (setcdr m (1- char)))))
- ranges))
-
-
-(defun rx-any-condense-range (args)
- "Condense by side effect ARGS as range for Rx `any'."
- (let (str
- l)
- ;; set STR list of all strings
- ;; set L list of all ranges
- (mapc (lambda (e) (cond ((stringp e) (push e str))
- ((numberp e) (push (cons e e) l))
- ;; Ranges between ASCII and raw bytes are split,
- ;; to prevent accidental inclusion of Unicode
- ;; characters later on.
- ((and (<= (car e) #x7f)
- (>= (cdr e) #x3fff80))
- (push (cons (car e) #x7f) l)
- (push (cons #x3fff80 (cdr e)) l))
- (t (push e l))))
- args)
- ;; condense overlapped ranges in L
- (let ((tail (setq l (sort l #'car-less-than-car)))
- d)
- (while (setq d (cdr tail))
- (if (>= (cdar tail) (1- (caar d)))
- (progn
- (setcdr (car tail) (max (cdar tail) (cdar d)))
- (setcdr tail (cdr d)))
- (setq tail d))))
- ;; Separate small ranges to single number, and delete dups.
- (nconc
- (apply #'nconc
- (mapcar (lambda (e)
- (cond
- ((= (car e) (cdr e)) (list (car e)))
- ((= (1+ (car e)) (cdr e)) (list (car e) (cdr e)))
- ((list e))))
- l))
- (delete-dups str))))
-
-
-(defun rx-check-any-string (str)
- "Turn the `any' argument string STR into a list of characters.
-The original order is not preserved. Ranges, \"A-Z\", become pairs, (?A . ?Z)."
+ ((null body) ; No items: a never-matching regexp.
+ (rx--empty))
+ ((null (cdr body)) ; Single item.
+ (rx--translate (car body)))
+ ((rx--every #'stringp body) ; All strings.
+ (cons (list (regexp-opt body nil t))
+ t))
+ (t
+ (cons (append (car (rx--translate (car body)))
+ (mapcan (lambda (item)
+ (cons "\\|" (car (rx--translate item))))
+ (cdr body)))
+ nil))))
+
+(defun rx--string-to-intervals (str)
+ "Decode STR as intervals: A-Z becomes (?A . ?Z), and the single
+character X becomes (?X . ?X). Return the intervals in a list."
+ ;; We could just do string-to-multibyte on the string and work with
+ ;; that instead of this `decode-char' workaround.
(let ((decode-char
- ;; Make sure raw bytes are decoded as such, to avoid confusion with
- ;; U+0080..U+00FF.
(if (multibyte-string-p str)
#'identity
- (lambda (c) (if (<= #x80 c #xff)
- (+ c #x3fff00)
- c))))
+ #'unibyte-char-to-multibyte))
(len (length str))
(i 0)
- (ret nil))
- (if (= 0 len)
- (error "String arg for Rx `any' must not be empty"))
+ (intervals nil))
(while (< i len)
(cond ((and (< i (- len 2))
- (= (aref str (+ i 1)) ?-))
+ (= (aref str (1+ i)) ?-))
;; Range.
(let ((start (funcall decode-char (aref str i)))
(end (funcall decode-char (aref str (+ i 2)))))
- (cond ((< start end) (push (cons start end) ret))
- ((= start end) (push start ret))
+ (cond ((and (<= start #x7f) (>= end #x3fff80))
+ ;; Ranges between ASCII and raw bytes are split to
+ ;; avoid having them absorb Unicode characters
+ ;; caught in-between.
+ (push (cons start #x7f) intervals)
+ (push (cons #x3fff80 end) intervals))
+ ((<= start end)
+ (push (cons start end) intervals))
(t
- (error "Rx character range `%c-%c' is reversed"
- start end)))
+ (error "Invalid rx `any' range: %s"
+ (substring str i 3))))
(setq i (+ i 3))))
(t
;; Single character.
- (push (funcall decode-char (aref str i)) ret)
+ (let ((char (funcall decode-char (aref str i))))
+ (push (cons char char) intervals))
(setq i (+ i 1)))))
- ret))
-
-
-(defun rx-check-any (arg)
- "Check arg ARG for Rx `any'."
- (cond
- ((integerp arg) (list arg))
- ((symbolp arg)
- (let ((translation (condition-case nil
- (rx-form arg)
- (error nil))))
- (if (or (null translation)
- (null (string-match "\\`\\[\\[:[-a-z]+:\\]\\]\\'" translation)))
- (error "Invalid char class `%s' in Rx `any'" arg))
- (list (substring translation 1 -1)))) ; strip outer brackets
- ((and (characterp (car-safe arg)) (characterp (cdr-safe arg)))
- (unless (<= (car arg) (cdr arg))
- (error "Rx character range `%c-%c' is reversed"
- (car arg) (cdr arg)))
- (list arg))
- ((stringp arg) (rx-check-any-string arg))
- ((error
- "rx `any' requires string, character, char pair or char class args"))))
-
-
-(defun rx-any (form)
- "Parse and produce code from FORM, which is `(any ARG ...)'.
-ARG is optional."
- (rx-check form)
- (let* ((args (rx-any-condense-range
- (apply
- #'nconc
- (mapcar #'rx-check-any (cdr form)))))
- m
- s)
- (cond
- ;; single close bracket
- ;; => "[]...-]" or "[]...--.]"
- ((memq ?\] args)
- ;; set ] at the beginning
- (setq args (cons ?\] (delq ?\] args)))
- ;; set - at the end
- (if (or (memq ?- args) (assq ?- args))
- (setq args (nconc (rx-any-delete-from-range ?- args)
- (list ?-)))))
- ;; close bracket starts a range
- ;; => "[]-....-]" or "[]-.--....]"
- ((setq m (assq ?\] args))
- ;; bring it to the beginning
- (setq args (cons m (delq m args)))
- (cond ((memq ?- args)
- ;; to the end
- (setq args (nconc (delq ?- args) (list ?-))))
- ((setq m (assq ?- args))
- ;; next to the bracket's range, make the second range
- (setcdr args (cons m (delq m (cdr args)))))))
- ;; bracket in the end range
- ;; => "[]...-]"
- ((setq m (rassq ?\] args))
- ;; set ] at the beginning
- (setq args (cons ?\] (rx-any-delete-from-range ?\] args)))
- ;; set - at the end
- (if (or (memq ?- args) (assq ?- args))
- (setq args (nconc (rx-any-delete-from-range ?- args)
- (list ?-)))))
- ;; {no close bracket appears}
- ;;
- ;; bring single bar to the beginning
- ((memq ?- args)
- (setq args (cons ?- (delq ?- args))))
- ;; bar start a range, bring it to the beginning
- ((setq m (assq ?- args))
- (setq args (cons m (delq m args))))
- ;;
- ;; hat at the beginning?
- ((or (eq (car args) ?^) (eq (car-safe (car args)) ?^))
- (setq args (if (cdr args)
- `(,(cadr args) ,(car args) ,@(cddr args))
- (nconc (rx-any-delete-from-range ?^ args)
- (list ?^))))))
- ;; some 1-char?
- (if (and (null (cdr args)) (numberp (car args))
- (or (= 1 (length
- (setq s (regexp-quote (string (car args))))))
- (and (equal (car args) ?^) ;; unnecessary predicate?
- (null (eq rx-parent '!)))))
- s
- (concat "["
- (mapconcat
- (lambda (e) (cond
- ((numberp e) (string e))
- ((consp e)
- (if (and (= (1+ (car e)) (cdr e))
- ;; rx-any-condense-range should
- ;; prevent this case from happening.
- (null (memq (car e) '(?\] ?-)))
- (null (memq (cdr e) '(?\] ?-))))
- (string (car e) (cdr e))
- (string (car e) ?- (cdr e))))
- (e)))
- args
- nil)
- "]"))))
-
-
-(defun rx-check-not (arg)
- "Check arg ARG for Rx `not'."
- (unless (or (and (symbolp arg)
- (string-match "\\`\\[\\[:[-a-z]+:\\]\\]\\'"
- (condition-case nil
- (rx-form arg)
- (error ""))))
- (eq arg 'word-boundary)
- (and (consp arg)
- (memq (car arg) '(not any in syntax category))))
- (error "rx `not' syntax error: %s" arg))
- t)
-
-
-(defun rx-not (form)
- "Parse and produce code from FORM. FORM is `(not ...)'."
- (rx-check form)
- (let ((result (rx-form (cadr form) '!))
- case-fold-search)
- (cond ((string-match "\\`\\[\\^" result)
- (cond
- ((equal result "[^]") "[^^]")
- ((and (= (length result) 4) (null (eq rx-parent '!)))
- (regexp-quote (substring result 2 3)))
- ((concat "[" (substring result 2)))))
- ((eq ?\[ (aref result 0))
- (concat "[^" (substring result 1)))
- ((string-match "\\`\\\\[scbw]" result)
- (concat (upcase (substring result 0 2))
- (substring result 2)))
- ((string-match "\\`\\\\[SCBW]" result)
- (concat (downcase (substring result 0 2))
- (substring result 2)))
- (t
- (concat "[^" result "]")))))
-
-
-(defun rx-not-char (form)
- "Parse and produce code from FORM. FORM is `(not-char ...)'."
- (rx-check form)
- (rx-not `(not (in ,@(cdr form)))))
-
-
-(defun rx-not-syntax (form)
- "Parse and produce code from FORM. FORM is `(not-syntax SYNTAX)'."
- (rx-check form)
- (rx-not `(not (syntax ,@(cdr form)))))
-
-
-(defun rx-trans-forms (form &optional skip)
- "If FORM's length is greater than two, transform it to length two.
-A form (HEAD REST ...) becomes (HEAD (and REST ...)).
-If SKIP is non-nil, allow that number of items after the head, i.e.
-`(= N REST ...)' becomes `(= N (and REST ...))' if SKIP is 1."
- (unless skip (setq skip 0))
- (let ((tail (nthcdr (1+ skip) form)))
- (if (= (length tail) 1)
- form
- (let ((form (copy-sequence form)))
- (setcdr (nthcdr skip form) (list (cons 'and tail)))
- form))))
-
-
-(defun rx-= (form)
- "Parse and produce code from FORM `(= N ...)'."
- (rx-check form)
- (setq form (rx-trans-forms form 1))
- (unless (and (integerp (nth 1 form))
- (> (nth 1 form) 0))
- (error "rx `=' requires positive integer first arg"))
- (let ((subform (rx-form (nth 2 form) '*)))
- (if (stringp subform)
- (format "%s\\{%d\\}" subform (nth 1 form))
- `(,@subform ,(format "\\{%d\\}" (nth 1 form))))))
-
-
-(defun rx->= (form)
- "Parse and produce code from FORM `(>= N ...)'."
- (rx-check form)
- (setq form (rx-trans-forms form 1))
- (unless (and (integerp (nth 1 form))
- (> (nth 1 form) 0))
- (error "rx `>=' requires positive integer first arg"))
- (let ((subform (rx-form (nth 2 form) '*)))
- (if (stringp subform)
- (format "%s\\{%d,\\}" subform (nth 1 form))
- `(,@subform ,(format "\\{%d,\\}" (nth 1 form))))))
-
-
-(defun rx-** (form)
- "Parse and produce code from FORM `(** N M ...)'."
- (rx-check form)
- (rx-form (cons 'repeat (cdr (rx-trans-forms form 2))) '*))
-
-
-(defun rx-repeat (form)
- "Parse and produce code from FORM.
-FORM is either `(repeat N FORM1)' or `(repeat N M FORMS...)'."
- (rx-check form)
- (if (> (length form) 4)
- (setq form (rx-trans-forms form 2)))
- (if (null (nth 2 form))
- (setq form (cons (nth 0 form) (cons (nth 1 form) (nthcdr 3 form)))))
- (cond ((= (length form) 3)
- (unless (and (integerp (nth 1 form))
- (> (nth 1 form) 0))
- (error "rx `repeat' requires positive integer first arg"))
- (let ((subform (rx-form (nth 2 form) '*)))
- (if (stringp subform)
- (format "%s\\{%d\\}" subform (nth 1 form))
- `(,@subform ,(format "\\{%d\\}" (nth 1 form))))))
- ((or (not (integerp (nth 2 form)))
- (< (nth 2 form) 0)
- (not (integerp (nth 1 form)))
- (< (nth 1 form) 0)
- (< (nth 2 form) (nth 1 form)))
- (error "rx `repeat' range error"))
- (t
- (let ((subform (rx-form (nth 3 form) '*)))
- (if (stringp subform)
- (format "%s\\{%d,%d\\}" subform (nth 1 form) (nth 2 form))
- `(,@subform ,(format "\\{%d,%d\\}" (nth 1 form) (nth 2 form))))))))
-
-
-(defun rx-submatch (form)
- "Parse and produce code from FORM, which is `(submatch ...)'."
- (let ((subforms (rx--subforms (cdr form) ':)))
- (if (stringp subforms)
- (concat "\\(" subforms "\\)")
- `("\\(" ,@subforms "\\)"))))
-
-(defun rx-submatch-n (form)
- "Parse and produce code from FORM, which is `(submatch-n N ...)'."
- (let ((n (nth 1 form))
- (subforms (rx--subforms (cddr form) ':)))
- (unless (and (integerp n) (> n 0))
- (error "rx `submatch-n' argument must be positive"))
- (if (stringp subforms)
- (concat "\\(?" (number-to-string n) ":" subforms "\\)")
- `("\\(?" ,(number-to-string n) ":" ,@subforms "\\)"))))
-
-(defun rx-backref (form)
- "Parse and produce code from FORM, which is `(backref N)'."
- (rx-check form)
- (format "\\%d" (nth 1 form)))
-
-(defun rx-check-backref (arg)
- "Check arg ARG for Rx `backref'."
- (or (and (integerp arg) (>= arg 1) (<= arg 9))
- (error "rx `backref' requires numeric 1<=arg<=9: %s" arg)))
-
-(defun rx-kleene (form)
- "Parse and produce code from FORM.
-FORM is `(OP FORM1)', where OP is one of the `zero-or-one',
-`zero-or-more' etc. operators.
-If OP is one of `*', `+', `?', produce a greedy regexp.
-If OP is one of `*?', `+?', `??', produce a non-greedy regexp.
-If OP is anything else, produce a greedy regexp if `rx-greedy-flag'
-is non-nil."
- (rx-check form)
- (setq form (rx-trans-forms form))
- (let ((suffix (cond ((memq (car form) '(* + \? ?\s)) "")
- ((memq (car form) '(*? +? \?? ??)) "?")
- (rx-greedy-flag "")
- (t "?")))
- (op (cond ((memq (car form) '(* *? 0+ zero-or-more)) "*")
- ((memq (car form) '(+ +? 1+ one-or-more)) "+")
- (t "?")))
- (subform (rx-form (cadr form) '*)))
- (rx-group-if
- (if (stringp subform)
- (concat subform op suffix)
- `(,@subform ,(concat op suffix)))
- (and (memq rx-parent '(t *)) rx-parent))))
-
-
-(defun rx-atomic-p (r &optional lax)
- "Return non-nil if regexp string R is atomic.
-An atomic regexp R is one such that a suffix operator
-appended to R will apply to all of R. For example, \"a\"
-\"[abc]\" and \"\\(ab\\|ab*c\\)\" are atomic and \"ab\",
-\"[ab]c\", and \"ab\\|ab*c\" are not atomic.
-
-This function may return false negatives, but it will not
-return false positives. It is nevertheless useful in
-situations where an efficiency shortcut can be taken only if a
-regexp is atomic. The function can be improved to detect
-more cases of atomic regexps. Presently, this function
-detects the following categories of atomic regexp;
-
- a group or shy group: \\(...\\)
- a character class: [...]
- a single character: a
-
-On the other hand, false negatives will be returned for
-regexps that are atomic but end in operators, such as
-\"a+\". I think these are rare. Probably such cases could
-be detected without much effort. A guarantee of no false
-negatives would require a theoretic specification of the set
-of all atomic regexps."
- (if (and rx--compile-to-lisp
- (not (stringp r)))
- nil ;; Runtime value, we must assume non-atomic.
- (let ((l (length r)))
+ intervals))
+
+(defun rx--condense-intervals (intervals)
+ "Merge adjacent and overlapping intervals by mutation, preserving the order.
+INTERVALS is a list of (START . END) with START ≤ END, sorted by START."
+ (let ((tail intervals)
+ d)
+ (while (setq d (cdr tail))
+ (if (>= (cdar tail) (1- (caar d)))
+ (progn
+ (setcdr (car tail) (max (cdar tail) (cdar d)))
+ (setcdr tail (cdr d)))
+ (setq tail d)))
+ intervals))
+
+(defun rx--translate-any (negated body)
+ "Translate an (any ...) construct. Return (REGEXP . PRECEDENCE).
+If NEGATED, negate the sense."
+ (let ((classes nil)
+ (strings nil)
+ (conses nil))
+ ;; Collect strings, conses and characters, and classes in separate bins.
+ (dolist (arg body)
+ (cond ((stringp arg)
+ (push arg strings))
+ ((and (consp arg)
+ (characterp (car arg))
+ (characterp (cdr arg))
+ (<= (car arg) (cdr arg)))
+ ;; Copy the cons, in case we need to modify it.
+ (push (cons (car arg) (cdr arg)) conses))
+ ((characterp arg)
+ (push (cons arg arg) conses))
+ ((and (symbolp arg)
+ (let ((class (cdr (assq arg rx--char-classes))))
+ (and class (push class classes)))))
+ (t (error "Invalid rx `any' argument: %s" arg))))
+ (let ((items
+ ;; Translate strings and conses into nonoverlapping intervals,
+ ;; and add classes as symbols at the end.
+ (append
+ (rx--condense-intervals
+ (sort (append conses
+ (mapcan #'rx--string-to-intervals strings))
+ #'car-less-than-car))
+ (reverse classes))))
+
+ ;; Move lone ] and range ]-x to the start.
+ (let ((rbrac-l (assq ?\] items)))
+ (when rbrac-l
+ (setq items (cons rbrac-l (delq rbrac-l items)))))
+
+ ;; Split x-] and move the lone ] to the start.
+ (let ((rbrac-r (rassq ?\] items)))
+ (when (and rbrac-r (not (eq (car rbrac-r) ?\])))
+ (setcdr rbrac-r ?\\)
+ (setq items (cons '(?\] . ?\]) items))))
+
+ ;; Split ,-- (which would end up as ,- otherwise).
+ (let ((dash-r (rassq ?- items)))
+ (when (eq (car dash-r) ?,)
+ (setcdr dash-r ?,)
+ (setq items (nconc items '((?- . ?-))))))
+
+ ;; Remove - (lone or at start of interval)
+ (let ((dash-l (assq ?- items)))
+ (when dash-l
+ (if (eq (cdr dash-l) ?-)
+ (setq items (delq dash-l items)) ; Remove lone -
+ (setcar dash-l ?.)) ; Reduce --x to .-x
+ (setq items (nconc items '((?- . ?-))))))
+
+ ;; Deal with leading ^ and range ^-x.
+ (when (and (consp (car items))
+ (eq (caar items) ?^)
+ (cdr items))
+ ;; Move ^ and ^-x to second place.
+ (setq items (cons (cadr items)
+ (cons (car items) (cddr items)))))
+
(cond
- ((<= l 1))
- ((= l 2) (= (aref r 0) ?\\))
- ((= l 3) (string-match "\\`\\(?:\\\\[cCsS_]\\|\\[[^^]\\]\\)" r))
- ((null lax)
- (cond
- ((string-match "\\`\\[\\^?]?\\(?:\\[:[a-z]+:]\\|[^]]\\)*]\\'" r))
- ((string-match "\\`\\\\(\\(?:[^\\]\\|\\\\[^)]\\)*\\\\)\\'" r))))))))
-
-
-(defun rx-syntax (form)
- "Parse and produce code from FORM, which is `(syntax SYMBOL)'."
- (rx-check form)
- (let* ((sym (cadr form))
- (syntax (cdr (assq sym rx-syntax))))
+ ;; Empty set: if negated, any char, otherwise match-nothing.
+ ((null items)
+ (if negated
+ (rx--translate-symbol 'anything)
+ (rx--empty)))
+ ;; Single non-negated character.
+ ((and (null (cdr items))
+ (consp (car items))
+ (eq (caar items) (cdar items))
+ (not negated))
+ (cons (list (regexp-quote (char-to-string (caar items))))
+ t))
+ ;; At least one character or class, possibly negated.
+ (t
+ (cons
+ (list
+ (concat
+ "["
+ (and negated "^")
+ (mapconcat (lambda (item)
+ (cond ((symbolp item)
+ (format "[:%s:]" item))
+ ((eq (car item) (cdr item))
+ (char-to-string (car item)))
+ ((eq (1+ (car item)) (cdr item))
+ (string (car item) (cdr item)))
+ (t
+ (string (car item) ?- (cdr item)))))
+ items nil)
+ "]"))
+ t))))))
+
+(defun rx--translate-not (negated body)
+ "Translate a (not ...) construct. Return (REGEXP . PRECEDENCE).
+If NEGATED, negate the sense (thus making it positive)."
+ (unless (and body (null (cdr body)))
+ (error "rx `not' form takes exactly one argument"))
+ (let ((arg (car body)))
+ (cond
+ ((consp arg)
+ (pcase (car arg)
+ ((or 'any 'in 'char) (rx--translate-any (not negated) (cdr arg)))
+ ('syntax (rx--translate-syntax (not negated) (cdr arg)))
+ ('category (rx--translate-category (not negated) (cdr arg)))
+ ('not (rx--translate-not (not negated) (cdr arg)))
+ (_ (error "Illegal argument to rx `not': %S" arg))))
+ ((eq arg 'word-boundary)
+ (rx--translate-symbol
+ (if negated 'word-boundary 'not-word-boundary)))
+ (t
+ (let ((class (cdr (assq arg rx--char-classes))))
+ (if class
+ (rx--translate-any (not negated) (list class))
+ (error "Illegal argument to rx `not': %s" arg)))))))
+
+(defun rx--atomic-regexp (item)
+ "ITEM is (REGEXP . PRECEDENCE); return a regexp of precedence t."
+ (if (eq (cdr item) t)
+ (car item)
+ (rx--bracket (car item))))
+
+(defun rx--translate-counted-repetition (min-count max-count body)
+ (let ((operand (rx--translate-seq body)))
+ (if (car operand)
+ (cons (append
+ (rx--atomic-regexp operand)
+ (list (concat "\\{"
+ (number-to-string min-count)
+ (cond ((null max-count) ",")
+ ((< min-count max-count)
+ (concat "," (number-to-string max-count))))
+ "\\}")))
+ t)
+ operand)))
+
+(defun rx--check-repeat-arg (name min-args body)
+ (unless (>= (length body) min-args)
+ (error "rx `%s' requires at least %d argument%s"
+ name min-args (if (= min-args 1) "" "s")))
+ ;; There seems to be no reason to disallow zero counts.
+ (unless (natnump (car body))
+ (error "rx `%s' first argument must be nonnegative" name)))
+
+(defun rx--translate-bounded-repetition (name body)
+ (let ((min-count (car body))
+ (max-count (cadr body))
+ (items (cddr body)))
+ (unless (and (natnump min-count)
+ (natnump max-count)
+ (<= min-count max-count))
+ (error "rx `%s' range error" name))
+ (rx--translate-counted-repetition min-count max-count items)))
+
+(defun rx--translate-repeat (body)
+ (rx--check-repeat-arg 'repeat 2 body)
+ (if (= (length body) 2)
+ (rx--translate-counted-repetition (car body) (car body) (cdr body))
+ (rx--translate-bounded-repetition 'repeat body)))
+
+(defun rx--translate-** (body)
+ (rx--check-repeat-arg '** 2 body)
+ (rx--translate-bounded-repetition '** body))
+
+(defun rx--translate->= (body)
+ (rx--check-repeat-arg '>= 1 body)
+ (rx--translate-counted-repetition (car body) nil (cdr body)))
+
+(defun rx--translate-= (body)
+ (rx--check-repeat-arg '= 1 body)
+ (rx--translate-counted-repetition (car body) (car body) (cdr body)))
+
+(defvar rx--greedy t)
+
+(defun rx--translate-rep (op-string greedy body)
+ "Translate a repetition; OP-STRING is one of \"*\", \"+\" or \"?\".
+GREEDY is a boolean. Return (REGEXP . PRECEDENCE)."
+ (let ((operand (rx--translate-seq body)))
+ (if (car operand)
+ (cons (append (rx--atomic-regexp operand)
+ (list (concat op-string (unless greedy "?"))))
+ ;; The result has precedence seq to avoid (? (* "a")) -> "a*?"
+ 'seq)
+ operand)))
+
+(defun rx--control-greedy (greedy body)
+ "Translate the sequence BODY with greediness GREEDY.
+Return (REGEXP . PRECEDENCE)."
+ (let ((rx--greedy greedy))
+ (rx--translate-seq body)))
+
+(defun rx--translate-group (body)
+ "Translate the `group' form. Return (REGEXP . PRECEDENCE)."
+ (cons (rx--enclose "\\("
+ (car (rx--translate-seq body))
+ "\\)")
+ t))
+
+(defun rx--translate-group-n (body)
+ "Translate the `group-n' form. Return (REGEXP . PRECEDENCE)."
+ (unless (and (integerp (car body)) (> (car body) 0))
+ (error "rx `group-n' requires a positive number as first argument"))
+ (cons (rx--enclose (concat "\\(?" (number-to-string (car body)) ":")
+ (car (rx--translate-seq (cdr body)))
+ "\\)")
+ t))
+
+(defun rx--translate-backref (body)
+ "Translate the `backref' form. Return (REGEXP . PRECEDENCE)."
+ (unless (and (= (length body) 1) (integerp (car body)) (<= 1 (car body) 9))
+ (error "rx `backref' requires an argument in the range 1..9"))
+ (cons (list "\\" (number-to-string (car body))) t))
+
+(defconst rx--syntax-codes
+ '((whitespace . ?-) ; SPC also accepted
+ (punctuation . ?.)
+ (word . ?w) ; W also accepted
+ (symbol . ?_)
+ (open-parenthesis . ?\()
+ (close-parenthesis . ?\))
+ (expression-prefix . ?\')
+ (string-quote . ?\")
+ (paired-delimiter . ?$)
+ (escape . ?\\)
+ (character-quote . ?/)
+ (comment-start . ?<)
+ (comment-end . ?>)
+ (string-delimiter . ?|)
+ (comment-delimiter . ?!)))
+
+(defun rx--translate-syntax (negated body)
+ "Translate the `syntax' form. Return (REGEXP . PRECEDENCE)."
+ (unless (and body (null (cdr body)))
+ (error "rx `syntax' form takes exactly one argument"))
+ (let* ((sym (car body))
+ (syntax (cdr (assq sym rx--syntax-codes))))
(unless syntax
- ;; Try sregex compatibility.
(cond
- ((characterp sym) (setq syntax sym))
+ ;; Syntax character directly (sregex compatibility)
+ ((and (characterp sym) (rassq sym rx--syntax-codes))
+ (setq syntax sym))
+ ;; Syntax character as symbol (sregex compatibility)
((symbolp sym)
(let ((name (symbol-name sym)))
- (if (= 1 (length name))
- (setq syntax (aref name 0))))))
+ (when (= (length name) 1)
+ (let ((char (string-to-char name)))
+ (when (rassq char rx--syntax-codes)
+ (setq syntax char)))))))
(unless syntax
- (error "Unknown rx syntax `%s'" sym)))
- (format "\\s%c" syntax)))
-
-
-(defun rx-check-category (form)
- "Check the argument FORM of a `(category FORM)'."
- (unless (or (integerp form)
- (cdr (assq form rx-categories)))
- (error "Unknown category `%s'" form))
- t)
-
-
-(defun rx-category (form)
- "Parse and produce code from FORM, which is `(category SYMBOL)'."
- (rx-check form)
- (let ((char (if (integerp (cadr form))
- (cadr form)
- (cdr (assq (cadr form) rx-categories)))))
- (format "\\c%c" char)))
-
-
-(defun rx-eval (form)
- "Parse and produce code from FORM, which is `(eval FORM)'."
- (rx-check form)
- (rx-form (eval (cadr form)) rx-parent))
-
-
-(defun rx-greedy (form)
- "Parse and produce code from FORM.
-If FORM is `(minimal-match FORM1)', non-greedy versions of `*',
-`+', and `?' operators will be used in FORM1. If FORM is
-`(maximal-match FORM1)', greedy operators will be used."
- (rx-check form)
- (let ((rx-greedy-flag (eq (car form) 'maximal-match)))
- (rx-form (cadr form) rx-parent)))
-
-
-(defun rx-regexp (form)
- "Parse and produce code from FORM, which is `(regexp STRING)'."
- (cond ((stringp (cadr form))
- (rx-group-if (cadr form) rx-parent))
- (rx--compile-to-lisp
- ;; Always group non-string forms, since we can't be sure they
- ;; are atomic.
- (rx-group-if (cdr form) t))
- (t (rx-check form))))
-
-(defun rx-literal (form)
- "Parse and produce code from FORM, which is `(literal STRING-EXP)'."
- (cond ((stringp (cadr form))
- ;; This is allowed, but makes little sense, you could just
- ;; use STRING directly.
- (rx-group-if (regexp-quote (cadr form)) rx-parent))
- (rx--compile-to-lisp
- (rx-group-if `((regexp-quote ,(cadr form))) rx-parent))
- (t (rx-check form))))
-
-(defun rx-form (form &optional parent)
- "Parse and produce code for regular expression FORM.
-FORM is a regular expression in sexp form.
-PARENT shows which type of expression calls and controls putting of
-shy groups around the result and some more in other functions."
- (let ((rx-parent parent))
- (cond
- ((stringp form)
- (rx-group-if (regexp-quote form)
- (if (and (eq parent '*) (< 1 (length form)))
- parent)))
- ((integerp form)
- (regexp-quote (char-to-string form)))
- ((symbolp form)
- (let ((info (rx-info form nil)))
- (cond ((stringp info)
- info)
- ((null info)
- (error "Unknown rx form `%s'" form))
- (t
- (funcall (nth 0 info) form)))))
- ((consp form)
- (let ((info (rx-info (car form) 'head)))
- (unless (consp info)
- (error "Unknown rx form `%s'" (car form)))
- (funcall (nth 0 info) form)))
- (t
- (error "rx syntax error at `%s'" form)))))
-
-(defun rx--subforms (subforms &optional parent separator)
- "Produce code for regular expressions SUBFORMS.
-SUBFORMS is a list of regular expression sexps.
-PARENT controls grouping, as in `rx-form'.
-Insert SEPARATOR between the code from each of SUBFORMS."
- (if (null (cdr subforms))
- ;; Zero or one forms, no need for grouping.
- (and subforms (rx-form (car subforms)))
- (let ((listify (lambda (x)
- (if (listp x) (copy-sequence x)
- (list x)))))
- (setq subforms (mapcar (lambda (x) (rx-form x parent)) subforms))
- (cond ((or (not rx--compile-to-lisp)
- (cl-every #'stringp subforms))
- (mapconcat #'identity subforms separator))
- (separator
- (nconc (funcall listify (car subforms))
- (mapcan (lambda (x)
- (cons separator (funcall listify x)))
- (cdr subforms))))
- (t (mapcan listify subforms))))))
+ (error "Unknown rx syntax name `%s'" sym)))
+ (cons (list (string ?\\ (if negated ?S ?s) syntax))
+ t)))
+
+(defconst rx--categories
+ '((space-for-indent . ?\s)
+ (base . ?.)
+ (consonant . ?0)
+ (base-vowel . ?1)
+ (upper-diacritical-mark . ?2)
+ (lower-diacritical-mark . ?3)
+ (tone-mark . ?4)
+ (symbol . ?5)
+ (digit . ?6)
+ (vowel-modifying-diacritical-mark . ?7)
+ (vowel-sign . ?8)
+ (semivowel-lower . ?9)
+ (not-at-end-of-line . ?<)
+ (not-at-beginning-of-line . ?>)
+ (alpha-numeric-two-byte . ?A)
+ (chinese-two-byte . ?C)
+ (chinse-two-byte . ?C) ; A typo in Emacs 21.1-24.3.
+ (greek-two-byte . ?G)
+ (japanese-hiragana-two-byte . ?H)
+ (indian-two-byte . ?I)
+ (japanese-katakana-two-byte . ?K)
+ (strong-left-to-right . ?L)
+ (korean-hangul-two-byte . ?N)
+ (strong-right-to-left . ?R)
+ (cyrillic-two-byte . ?Y)
+ (combining-diacritic . ?^)
+ (ascii . ?a)
+ (arabic . ?b)
+ (chinese . ?c)
+ (ethiopic . ?e)
+ (greek . ?g)
+ (korean . ?h)
+ (indian . ?i)
+ (japanese . ?j)
+ (japanese-katakana . ?k)
+ (latin . ?l)
+ (lao . ?o)
+ (tibetan . ?q)
+ (japanese-roman . ?r)
+ (thai . ?t)
+ (vietnamese . ?v)
+ (hebrew . ?w)
+ (cyrillic . ?y)
+ (can-break . ?|)))
+
+(defun rx--translate-category (negated body)
+ "Translate the `category' form. Return (REGEXP . PRECEDENCE)."
+ (unless (and body (null (cdr body)))
+ (error "rx `category' form takes exactly one argument"))
+ (let* ((arg (car body))
+ (category
+ (cond ((symbolp arg)
+ (let ((cat (assq arg rx--categories)))
+ (unless cat
+ (error "Unknown rx category `%s'" arg))
+ (cdr cat)))
+ ((characterp arg) arg)
+ (t (error "Invalid rx `category' argument `%s'" arg)))))
+ (cons (list (string ?\\ (if negated ?C ?c) category))
+ t)))
+
+(defvar rx--delayed-evaluation nil
+ "Whether to allow certain forms to be evaluated at runtime.")
+
+(defun rx--translate-literal (body)
+ "Translate the `literal' form. Return (REGEXP . PRECEDENCE)."
+ (unless (and body (null (cdr body)))
+ (error "rx `literal' form takes exactly one argument"))
+ (let ((arg (car body)))
+ (cond ((stringp arg)
+ (cons (list (regexp-quote arg)) (if (= (length arg) 1) t 'seq)))
+ (rx--delayed-evaluation
+ (cons (list (list 'regexp-quote arg)) 'seq))
+ (t (error "rx `literal' form with non-string argument")))))
+
+(defun rx--translate-eval (body)
+ "Translate the `eval' form. Return (REGEXP . PRECEDENCE)."
+ (unless (and body (null (cdr body)))
+ (error "rx `eval' form takes exactly one argument"))
+ (rx--translate (eval (car body))))
+
+(defvar rx--regexp-atomic-regexp nil)
+
+(defun rx--translate-regexp (body)
+ "Translate the `regexp' form. Return (REGEXP . PRECEDENCE)."
+ (unless (and body (null (cdr body)))
+ (error "rx `regexp' form takes exactly one argument"))
+ (let ((arg (car body)))
+ (cond ((stringp arg)
+ ;; Generate the regexp when needed, since rx isn't
+ ;; necessarily present in the byte-compilation environment.
+ (unless rx--regexp-atomic-regexp
+ (setq rx--regexp-atomic-regexp
+ ;; Match atomic (precedence t) regexps: may give
+ ;; false negatives but no false positives, assuming
+ ;; the target string is syntactically correct.
+ (rx-to-string
+ '(seq
+ bos
+ (or (seq "["
+ (opt "^")
+ (opt "]")
+ (* (or (seq "[:" (+ (any "a-z")) ":]")
+ (not (any "]"))))
+ "]")
+ anything
+ (seq "\\"
+ (or anything
+ (seq (any "sScC_") anything)
+ (seq "("
+ (* (or (not (any "\\"))
+ (seq "\\" (not (any ")")))))
+ "\\)"))))
+ eos)
+ t)))
+ (cons (list arg)
+ (if (string-match-p rx--regexp-atomic-regexp arg) t nil)))
+ (rx--delayed-evaluation
+ (cons (list arg) nil))
+ (t (error "rx `regexp' form with non-string argument")))))
+
+(defun rx--translate-compat-form (def form)
+ "Translate a compatibility form from `rx-constituents'.
+DEF is the definition tuple. Return (REGEXP . PRECEDENCE)."
+ (let* ((fn (nth 0 def))
+ (min-args (nth 1 def))
+ (max-args (nth 2 def))
+ (predicate (nth 3 def))
+ (nargs (1- (length form))))
+ (when (< nargs min-args)
+ (error "The `%s' form takes at least %d argument(s)"
+ (car form) min-args))
+ (when (and max-args (> nargs max-args))
+ (error "The `%s' form takes at most %d argument(s)"
+ (car form) max-args))
+ (when (and predicate (not (rx--every predicate (cdr form))))
+ (error "The `%s' form requires arguments satisfying `%s'"
+ (car form) predicate))
+ (let ((regexp (funcall fn form)))
+ (unless (stringp regexp)
+ (error "The `%s' form did not expand to a string" (car form)))
+ (cons (list regexp) nil))))
+
+(defun rx--translate-form (form)
+ "Translate an rx form (list structure). Return (REGEXP . PRECEDENCE)."
+ (let ((body (cdr form)))
+ (pcase (car form)
+ ((or 'seq : 'and 'sequence) (rx--translate-seq body))
+ ((or 'or '|) (rx--translate-or body))
+ ((or 'any 'in 'char) (rx--translate-any nil body))
+ ('not-char (rx--translate-any t body))
+ ('not (rx--translate-not nil body))
+
+ ('repeat (rx--translate-repeat body))
+ ('= (rx--translate-= body))
+ ('>= (rx--translate->= body))
+ ('** (rx--translate-** body))
+
+ ((or 'zero-or-more '0+) (rx--translate-rep "*" rx--greedy body))
+ ((or 'one-or-more '1+) (rx--translate-rep "+" rx--greedy body))
+ ((or 'zero-or-one 'opt 'optional) (rx--translate-rep "?" rx--greedy body))
+
+ ('* (rx--translate-rep "*" t body))
+ ('+ (rx--translate-rep "+" t body))
+ ((or '\? ?\s) (rx--translate-rep "?" t body))
+
+ ('*? (rx--translate-rep "*" nil body))
+ ('+? (rx--translate-rep "+" nil body))
+ ((or '\?? ??) (rx--translate-rep "?" nil body))
+
+ ('minimal-match (rx--control-greedy nil body))
+ ('maximal-match (rx--control-greedy t body))
+
+ ((or 'group 'submatch) (rx--translate-group body))
+ ((or 'group-n 'submatch-n) (rx--translate-group-n body))
+ ('backref (rx--translate-backref body))
+
+ ('syntax (rx--translate-syntax nil body))
+ ('not-syntax (rx--translate-syntax t body))
+ ('category (rx--translate-category nil body))
+
+ ('literal (rx--translate-literal body))
+ ('eval (rx--translate-eval body))
+ ((or 'regexp 'regex) (rx--translate-regexp body))
+
+ (op
+ (unless (symbolp op)
+ (error "Bad rx operator `%S'" op))
+
+ ;; For compatibility with old rx.
+ (let ((entry (assq op rx-constituents)))
+ (if (progn
+ (while (and entry (not (consp (cdr entry))))
+ (setq entry
+ (if (symbolp (cdr entry))
+ ;; Alias for another entry.
+ (assq (cdr entry) rx-constituents)
+ ;; Wrong type, try further down the list.
+ (assq (car entry)
+ (cdr (memq entry rx-constituents))))))
+ entry)
+ (rx--translate-compat-form (cdr entry) form)
+ (error "Unknown rx form `%s'" op)))))))
+
+;; Defined here rather than in re-builder to lower the odds that it
+;; will be kept in sync with changes.
+(defconst rx--builtin-forms
+ '(seq sequence : and or | any in char not-char not
+ repeat = >= **
+ zero-or-more 0+ *
+ one-or-more 1+ +
+ zero-or-one opt optional \?
+ *? +? \??
+ minimal-match maximal-match
+ group submatch group-n submatch-n backref
+ syntax not-syntax category
+ literal eval regexp regex)
+ "List of built-in rx forms. For use in re-builder only.")
+
+(defun rx--translate (item)
+ "Translate the rx-expression ITEM. Return (REGEXP . PRECEDENCE)."
+ (cond
+ ((stringp item)
+ (if (= (length item) 0)
+ (cons nil 'seq)
+ (cons (list (regexp-quote item)) (if (= (length item) 1) t 'seq))))
+ ((characterp item)
+ (cons (list (regexp-quote (char-to-string item))) t))
+ ((symbolp item)
+ (rx--translate-symbol item))
+ ((consp item)
+ (rx--translate-form item))
+ (t (error "Bad rx expression: %S" item))))
;;;###autoload
(defun rx-to-string (form &optional no-group)
- "Parse and produce code for regular expression FORM.
-FORM is a regular expression in sexp form.
-NO-GROUP non-nil means don't put shy groups around the result.
-
-In contrast to the `rx' macro, subforms `literal' and `regexp'
-will not accept non-string arguments, i.e., (literal STRING)
-becomes just a more verbose version of STRING."
- (rx-group-if (rx-form form) (null no-group)))
+ "Translate FORM from `rx' sexp syntax into a string regexp.
+The arguments to `literal' and `regexp' forms inside FORM must be
+constant strings.
+If NO-GROUP is non-nil, don't bracket the result in a non-capturing
+group."
+ (let* ((item (rx--translate form))
+ (exprs (if no-group
+ (car item)
+ (rx--atomic-regexp item))))
+ (apply #'concat exprs)))
+
+(defun rx--to-expr (form)
+ "Translate the rx-expression FORM to a Lisp expression yielding a regexp."
+ (let* ((rx--delayed-evaluation t)
+ (elems (car (rx--translate form)))
+ (args nil))
+ ;; Merge adjacent strings.
+ (while elems
+ (let ((strings nil))
+ (while (and elems (stringp (car elems)))
+ (push (car elems) strings)
+ (setq elems (cdr elems)))
+ (let ((s (apply #'concat (nreverse strings))))
+ (unless (zerop (length s))
+ (push s args))))
+ (when elems
+ (push (car elems) args)
+ (setq elems (cdr elems))))
+ (cond ((null args) "") ; 0 args
+ ((cdr args) (cons 'concat (nreverse args))) ; ≥2 args
+ (t (car args))))) ; 1 arg
;;;###autoload
@@ -1054,78 +937,64 @@ rx
(literal EXPR) Match the literal string from evaluating EXPR at run time.
(regexp EXPR) Match the string regexp from evaluating EXPR at run time.
-(eval EXPR) Match the rx sexp from evaluating EXPR at compile time."
- (let* ((rx--compile-to-lisp t)
- (re (cond ((null regexps)
- (error "No regexp"))
- ((cdr regexps)
- (rx-to-string `(and ,@regexps) t))
- (t
- (rx-to-string (car regexps) t)))))
- (if (stringp re)
- re
- `(concat ,@re))))
-
+(eval EXPR) Match the rx sexp from evaluating EXPR at compile time.
+
+\(fn REGEXPS...)"
+ (rx--to-expr (cons 'seq regexps)))
+
+
+;; During `rx--pcase-transform', list of defined variables in right-to-left
+;; order.
+(defvar rx--pcase-vars)
+
+(defun rx--pcase-transform (rx)
+ "Transform RX, an rx-expression augmented with `let' and named `backref',
+into a plain rx-expression, collecting names into `rx--pcase-vars'."
+ (pcase rx
+ (`(let ,name . ,body)
+ (let* ((index (length (memq name rx--pcase-vars)))
+ (i (if (zerop index)
+ (length (push name rx--pcase-vars))
+ index)))
+ `(group-n ,i ,(rx--pcase-transform (cons 'seq body)))))
+ ((and `(backref ,ref)
+ (guard (symbolp ref)))
+ (let ((index (length (memq ref rx--pcase-vars))))
+ (when (zerop index)
+ (error "rx `backref' variable must be one of: %s"
+ (mapconcat #'symbol-name rx--pcase-vars " ")))
+ `(backref ,index)))
+ ((and `(,head . ,rest)
+ (guard (and (symbolp head)
+ (not (memq head '(literal regexp regex eval))))))
+ (cons head (mapcar #'rx--pcase-transform rest)))
+ (_ rx)))
(pcase-defmacro rx (&rest regexps)
- "Build a `pcase' pattern matching `rx' REGEXPS in sexp form.
-The REGEXPS are interpreted as in `rx'. The pattern matches any
-string that is a match for the regular expression so constructed,
-as if by `string-match'.
+ "A pattern that matches strings against `rx' REGEXPS in sexp form.
+REGEXPS are interpreted as in `rx'. The pattern matches any
+string that is a match for REGEXPS, as if by `string-match'.
-In addition to the usual `rx' constructs, REGEXPS can contain the
+In addition to the usual `rx' syntax, REGEXPS can contain the
following constructs:
- (let REF SEXP...) creates a new explicitly named reference to
- a submatch that matches regular expressions
- SEXP, and binds the match to REF.
- (backref REF) creates a backreference to the submatch
- introduced by a previous (let REF ...)
- construct. REF can be the same symbol
- in the first argument of the corresponding
- (let REF ...) construct, or it can be a
- submatch number. It matches the referenced
- submatch.
-
-The REFs are associated with explicitly named submatches starting
-from 1. Multiple occurrences of the same REF refer to the same
-submatch.
-
-If a case matches, the match data is modified as usual so you can
-use it in the case body, but you still have to pass the correct
-string as argument to `match-string'."
- (let* ((vars ())
- (rx-constituents
- `((let
- ,(lambda (form)
- (rx-check form)
- (let ((var (cadr form)))
- (cl-check-type var symbol)
- (let ((i (or (cl-position var vars :test #'eq)
- (prog1 (length vars)
- (setq vars `(,@vars ,var))))))
- (rx-form `(submatch-n ,(1+ i) ,@(cddr form))))))
- 1 nil)
- (backref
- ,(lambda (form)
- (rx-check form)
- (rx-backref
- `(backref ,(let ((var (cadr form)))
- (if (integerp var) var
- (1+ (cl-position var vars :test #'eq)))))))
- 1 1
- ,(lambda (var)
- (cond ((integerp var) (rx-check-backref var))
- ((memq var vars) t)
- (t (error "rx `backref' variable must be one of %s: %s"
- vars var)))))
- ,@rx-constituents))
- (regexp (rx-to-string `(seq ,@regexps) :no-group)))
+ (let REF RX...) binds the symbol REF to a submatch that matches
+ the regular expressions RX. REF is bound in
+ CODE to the string of the submatch or nil, but
+ can also be used in `backref'.
+ (backref REF) matches whatever the submatch REF matched.
+ REF can be a number, as usual, or a name
+ introduced by a previous (let REF ...)
+ construct."
+ (let* ((rx--pcase-vars nil)
+ (regexp (rx--to-expr (rx--pcase-transform (cons 'seq regexps)))))
`(and (pred (string-match ,regexp))
- ,@(cl-loop for i from 1
- for var in vars
- collect `(app (match-string ,i) ,var)))))
-\f
+ ,@(let ((i 0))
+ (mapcar (lambda (name)
+ (setq i (1+ i))
+ `(app (match-string ,i) ,name))
+ (reverse rx--pcase-vars))))))
+
(provide 'rx)
;;; rx.el ends here
diff --git a/test/lisp/emacs-lisp/rx-tests.el b/test/lisp/emacs-lisp/rx-tests.el
index 8845ebf46d..fec046dd99 100644
--- a/test/lisp/emacs-lisp/rx-tests.el
+++ b/test/lisp/emacs-lisp/rx-tests.el
@@ -1,4 +1,4 @@
-;;; rx-tests.el --- test for rx.el functions -*- lexical-binding: t -*-
+;;; rx-tests.el --- tests for rx.el -*- lexical-binding: t -*-
;; Copyright (C) 2016-2019 Free Software Foundation, Inc.
@@ -17,21 +17,44 @@
;; You should have received a copy of the GNU General Public License
;; along with GNU Emacs. If not, see <https://www.gnu.org/licenses/>.
-;;; Commentary:
-
(require 'ert)
(require 'rx)
-;;; Code:
+(ert-deftest rx-seq ()
+ (should (equal (rx "a.b" "*" "c")
+ "a\\.b\\*c"))
+ (should (equal (rx (seq "a" (: "b" (and "c" (sequence "d" nonl)
+ "e")
+ "f")
+ "g"))
+ "abcd.efg"))
+ (should (equal (rx "a$" "b")
+ "a\\$b"))
+ (should (equal (rx bol "a" "b" ?c eol)
+ "^abc$"))
+ (should (equal (rx "a" "" "b")
+ "ab"))
+ (should (equal (rx (seq))
+ ""))
+ (should (equal (rx "" (or "ab" nonl) "")
+ "ab\\|.")))
+
+(ert-deftest rx-or ()
+ (should (equal (rx (or "ab" (| "c" nonl) "de"))
+ "ab\\|c\\|.\\|de"))
+ (should (equal (rx (or "ab" "abc" "a"))
+ "\\(?:ab\\|abc\\|a\\)"))
+ (should (equal (rx (| nonl "a") (| "b" blank))
+ "\\(?:.\\|a\\)\\(?:b\\|[[:blank:]]\\)"))
+ (should (equal (rx (|))
+ "\\`a\\`")))
(ert-deftest rx-char-any ()
"Test character alternatives with `]' and `-' (Bug#25123)."
- (should (string-match
+ (should (equal
(rx string-start (1+ (char (?\] . ?\{) (?< . ?\]) (?- . ?:)))
string-end)
- (apply #'string (nconc (number-sequence ?\] ?\{)
- (number-sequence ?< ?\])
- (number-sequence ?- ?:))))))
+ "\\`[.-:<-{-]+\\'")))
(ert-deftest rx-char-any-range-nl ()
"Test character alternatives with LF as a range endpoint."
@@ -40,28 +63,72 @@ rx-char-any-range-nl
(should (equal (rx (any "\a-\n"))
"[\a-\n]")))
-(ert-deftest rx-char-any-range-bad ()
- (should-error (rx (any "0-9a-Z")))
- (should-error (rx (any (?0 . ?9) (?a . ?Z)))))
-
(ert-deftest rx-char-any-raw-byte ()
"Test raw bytes in character alternatives."
+
+ ;; The multibyteness of the rx return value sometimes depends on whether
+ ;; the test had been byte-compiled or not, so we add explicit conversions.
+
;; Separate raw characters.
- (should (equal (string-match-p (rx (any "\326A\333B"))
- "X\326\333")
- 1))
+ (should (equal (string-to-multibyte (rx (any "\326A\333B")))
+ (string-to-multibyte "[AB\326\333]")))
;; Range of raw characters, unibyte.
- (should (equal (string-match-p (rx (any "\200-\377"))
- "ÿA\310B")
- 2))
+ (should (equal (string-to-multibyte (rx (any "\200-\377")))
+ (string-to-multibyte "[\200-\377]")))
+
;; Range of raw characters, multibyte.
- (should (equal (string-match-p (rx (any "Å\211\326-\377\177"))
- "XY\355\177\327")
- 2))
+ (should (equal (rx (any "Å\211\326-\377\177"))
+ "[\177Å\211\326-\377]"))
;; Split range; \177-\377ÿ should not be optimised to \177-\377.
- (should (equal (string-match-p (rx (any "\177-\377" ?ÿ))
- "ÿA\310B")
- 0)))
+ (should (equal (rx (any "\177-\377" ?ÿ))
+ "[\177ÿ\200-\377]")))
+
+(ert-deftest rx-any ()
+ (should (equal (rx (any ?A (?C . ?D) "F-H" "J-L" "M" "N-P" "Q" "RS"))
+ "[ACDF-HJ-S]"))
+ (should (equal (rx (in "a!f" ?c) (char "q-z" "0-3")
+ (not-char "a-e1-5") (not (in "A-M" ?q)))
+ "[!acf][0-3q-z][^1-5a-e][^A-Mq]"))
+ (should (equal (rx (any "^") (any "]") (any "-")
+ (not (any "^")) (not (any "]")) (not (any "-")))
+ "\\^]-[^^][^]][^-]"))
+ (should (equal (rx (any "]" "^") (any "]" "-") (any "-" "^")
+ (not (any "]" "^")) (not (any "]" "-"))
+ (not (any "-" "^")))
+ "[]^][]-][-^][^]^][^]-][^-^]"))
+ (should (equal (rx (any "]" "^" "-") (not (any "]" "^" "-")))
+ "[]^-][^]^-]"))
+ (should (equal (rx (any "-" ascii) (any "^" ascii) (any "]" ascii))
+ "[[:ascii:]-][[:ascii:]^][][:ascii:]]"))
+ (should (equal (rx (not (any "-" ascii)) (not (any "^" ascii))
+ (not (any "]" ascii)))
+ "[^[:ascii:]-][^[:ascii:]^][^][:ascii:]]"))
+ (should (equal (rx (any "-]" ascii) (any "^]" ascii) (any "-^" ascii))
+ "[][:ascii:]-][]^[:ascii:]][[:ascii:]^-]"))
+ (should (equal (rx (not (any "-]" ascii)) (not (any "^]" ascii))
+ (not (any "-^" ascii)))
+ "[^][:ascii:]-][^]^[:ascii:]][^[:ascii:]^-]"))
+ (should (equal (rx (any "-]^" ascii) (not (any "-]^" ascii)))
+ "[]^[:ascii:]-][^]^[:ascii:]-]"))
+ (should (equal (rx (any "^" lower upper) (not (any "^" lower upper)))
+ "[[:lower:]^[:upper:]][^[:lower:]^[:upper:]]"))
+ (should (equal (rx (any "-" lower upper) (not (any "-" lower upper)))
+ "[[:lower:][:upper:]-][^[:lower:][:upper:]-]"))
+ (should (equal (rx (any "]" lower upper) (not (any "]" lower upper)))
+ "[][:lower:][:upper:]][^][:lower:][:upper:]]"))
+ (should (equal (rx (any "-a" "c-" "f-f" "--/*--"))
+ "[*-/acf]"))
+ (should (equal (rx (any "]-a" ?-) (not (any "]-a" ?-)))
+ "[]-a-][^]-a-]"))
+ (should (equal (rx (any "--]") (not (any "--]"))
+ (any "-" "^-a") (not (any "-" "^-a")))
+ "[].-\\-][^].-\\-][-^-a][^-^-a]"))
+ (should (equal (rx (not (any "!a" "0-8" digit nonascii)))
+ "[^!0-8a[:digit:][:nonascii:]]"))
+ (should (equal (rx (any) (not (any)))
+ "\\`a\\`\\(?:.\\|\n\\)"))
+ (should (equal (rx (any "") (not (any "")))
+ "\\`a\\`\\(?:.\\|\n\\)")))
(ert-deftest rx-pcase ()
(should (equal (pcase "a 1 2 3 1 1 b"
@@ -71,7 +138,11 @@ rx-pcase
(backref u) space
(backref 1))
(list u v)))
- '("1" "3"))))
+ '("1" "3")))
+ (let ((k "blue"))
+ (should (equal (pcase "<blue>"
+ ((rx "<" (literal k) ">") 'ok))
+ 'ok))))
(ert-deftest rx-kleene ()
"Test greedy and non-greedy repetition operators."
@@ -94,71 +165,158 @@ rx-kleene
(should (equal (rx (maximal-match
(seq (* "a") (+ "b") (\? "c") (?\s "d")
(*? "e") (+? "f") (\?? "g") (?? "h"))))
- "a*b+c?d?e*?f+?g??h??")))
+ "a*b+c?d?e*?f+?g??h??"))
+ (should (equal (rx "a" (*) (+ (*)) (? (*) (+)) "b")
+ "ab")))
-(ert-deftest rx-or ()
- ;; Test or-pattern reordering (Bug#34641).
- (let ((s "abc"))
- (should (equal (and (string-match (rx (or "abc" "ab" "a")) s)
- (match-string 0 s))
- "abc"))
- (should (equal (and (string-match (rx (or "ab" "abc" "a")) s)
- (match-string 0 s))
- "ab"))
- (should (equal (and (string-match (rx (or "a" "ab" "abc")) s)
- (match-string 0 s))
- "a")))
- ;; Test zero-argument `or'.
- (should (equal (rx (or)) regexp-unmatchable)))
+(ert-deftest rx-repeat ()
+ (should (equal (rx (= 3 "a") (>= 51 "b")
+ (** 2 11 "c") (repeat 6 "d") (repeat 4 8 "e"))
+ "a\\{3\\}b\\{51,\\}c\\{2,11\\}d\\{6\\}e\\{4,8\\}"))
+ (should (equal (rx (= 0 "k") (>= 0 "l") (** 0 0 "m") (repeat 0 "n")
+ (repeat 0 0 "o"))
+ "k\\{0\\}l\\{0,\\}m\\{0\\}n\\{0\\}o\\{0\\}"))
+ (should (equal (rx (opt (0+ "a")))
+ "\\(?:a*\\)?"))
+ (should (equal (rx (opt (= 4 "a")))
+ "a\\{4\\}?"))
+ (should (equal (rx "a" (** 3 7) (= 4) (>= 3) (= 4 (>= 7) (= 2)) "b")
+ "ab")))
+
+(ert-deftest rx-atoms ()
+ (should (equal (rx anything)
+ ".\\|\n"))
+ (should (equal (rx line-start not-newline nonl any line-end)
+ "^...$"))
+ (should (equal (rx bol string-start string-end buffer-start buffer-end
+ bos eos bot eot eol)
+ "^\\`\\'\\`\\'\\`\\'\\`\\'$"))
+ (should (equal (rx point word-start word-end bow eow symbol-start symbol-end
+ word-boundary not-word-boundary not-wordchar)
+ "\\=\\<\\>\\<\\>\\_<\\_>\\b\\B\\W"))
+ (should (equal (rx digit numeric num control cntrl)
+ "[[:digit:]][[:digit:]][[:digit:]][[:cntrl:]][[:cntrl:]]"))
+ (should (equal (rx hex-digit hex xdigit blank)
+ "[[:xdigit:]][[:xdigit:]][[:xdigit:]][[:blank:]]"))
+ (should (equal (rx graph graphic print printing)
+ "[[:graph:]][[:graph:]][[:print:]][[:print:]]"))
+ (should (equal (rx alphanumeric alnum letter alphabetic alpha)
+ "[[:alnum:]][[:alnum:]][[:alpha:]][[:alpha:]][[:alpha:]]"))
+ (should (equal (rx ascii nonascii lower lower-case)
+ "[[:ascii:]][[:nonascii:]][[:lower:]][[:lower:]]"))
+ (should (equal (rx punctuation punct space whitespace white)
+ "[[:punct:]][[:punct:]][[:space:]][[:space:]][[:space:]]"))
+ (should (equal (rx upper upper-case word wordchar)
+ "[[:upper:]][[:upper:]][[:word:]][[:word:]]"))
+ (should (equal (rx unibyte multibyte)
+ "[[:unibyte:]][[:multibyte:]]")))
+
+(ert-deftest rx-syntax ()
+ (should (equal (rx (syntax whitespace) (syntax punctuation)
+ (syntax word) (syntax symbol)
+ (syntax open-parenthesis) (syntax close-parenthesis))
+ "\\s-\\s.\\sw\\s_\\s(\\s)"))
+ (should (equal (rx (syntax string-quote) (syntax paired-delimiter)
+ (syntax escape) (syntax character-quote)
+ (syntax comment-start) (syntax comment-end)
+ (syntax string-delimiter) (syntax comment-delimiter))
+ "\\s\"\\s$\\s\\\\s/\\s<\\s>\\s|\\s!")))
+
+(ert-deftest rx-category ()
+ (should (equal (rx (category space-for-indent) (category base)
+ (category consonant) (category base-vowel)
+ (category upper-diacritical-mark)
+ (category lower-diacritical-mark)
+ (category tone-mark) (category symbol)
+ (category digit)
+ (category vowel-modifying-diacritical-mark)
+ (category vowel-sign) (category semivowel-lower)
+ (category not-at-end-of-line)
+ (category not-at-beginning-of-line))
+ "\\c \\c.\\c0\\c1\\c2\\c3\\c4\\c5\\c6\\c7\\c8\\c9\\c<\\c>"))
+ (should (equal (rx (category alpha-numeric-two-byte)
+ (category chinese-two-byte) (category greek-two-byte)
+ (category japanese-hiragana-two-byte)
+ (category indian-two-byte)
+ (category japanese-katakana-two-byte)
+ (category strong-left-to-right)
+ (category korean-hangul-two-byte)
+ (category strong-right-to-left)
+ (category cyrillic-two-byte)
+ (category combining-diacritic))
+ "\\cA\\cC\\cG\\cH\\cI\\cK\\cL\\cN\\cR\\cY\\c^"))
+ (should (equal (rx (category ascii) (category arabic) (category chinese)
+ (category ethiopic) (category greek) (category korean)
+ (category indian) (category japanese)
+ (category japanese-katakana) (category latin)
+ (category lao) (category tibetan))
+ "\\ca\\cb\\cc\\ce\\cg\\ch\\ci\\cj\\ck\\cl\\co\\cq"))
+ (should (equal (rx (category japanese-roman) (category thai)
+ (category vietnamese) (category hebrew)
+ (category cyrillic) (category can-break))
+ "\\cr\\ct\\cv\\cw\\cy\\c|"))
+ (should (equal (rx (category ?g) (not (category ?~)))
+ "\\cg\\C~")))
+
+(ert-deftest rx-not ()
+ (should (equal (rx (not word-boundary))
+ "\\B"))
+ (should (equal (rx (not ascii) (not lower-case) (not wordchar))
+ "[^[:ascii:]][^[:lower:]][^[:word:]]"))
+ (should (equal (rx (not (syntax punctuation)) (not (syntax escape)))
+ "\\S.\\S\\"))
+ (should (equal (rx (not (category tone-mark)) (not (category lao)))
+ "\\C4\\Co")))
+
+(ert-deftest rx-group ()
+ (should (equal (rx (group nonl) (submatch "x")
+ (group-n 3 "y") (submatch-n 13 "z") (backref 1))
+ "\\(.\\)\\(x\\)\\(?3:y\\)\\(?13:z\\)\\1"))
+ (should (equal (rx (group) (group-n 2))
+ "\\(\\)\\(?2:\\)")))
+
+(ert-deftest rx-regexp ()
+ (should (equal (rx (regexp "abc") (regex "[de]"))
+ "\\(?:abc\\)[de]"))
+ (let ((x "a*"))
+ (should (equal (rx (regexp x) "b")
+ "\\(?:a*\\)b"))
+ (should (equal (rx "" (regexp x) (eval ""))
+ "a*"))))
+
+(ert-deftest rx-eval ()
+ (should (equal (rx (eval (list 'syntax 'symbol)))
+ "\\s_"))
+ (should (equal (rx "a" (eval (concat)) "b")
+ "ab")))
+
+(ert-deftest rx-literal ()
+ (should (equal (rx (literal (char-to-string 42)) nonl)
+ "\\*."))
+ (let ((x "a+b"))
+ (should (equal (rx (opt (literal (upcase x))))
+ "\\(?:A\\+B\\)?"))))
+
+(ert-deftest rx-to-string ()
+ (should (equal (rx-to-string '(or nonl "\nx"))
+ "\\(?:.\\|\nx\\)"))
+ (should (equal (rx-to-string '(or nonl "\nx") t)
+ ".\\|\nx")))
+
+
+(ert-deftest rx-constituents ()
+ (let ((rx-constituents
+ (append '((beta . gamma)
+ (gamma . "a*b")
+ (delta . ((lambda (form)
+ (regexp-quote (format "<%S>" form)))
+ 1 nil symbolp))
+ (epsilon . delta))
+ rx-constituents)))
+ (should (equal (rx-to-string '(seq (+ beta) nonl gamma) t)
+ "\\(?:a*b\\)+.\\(?:a*b\\)"))
+ (should (equal (rx-to-string '(seq (delta a b c) (* (epsilon d e))) t)
+ "\\(?:<(delta a b c)>\\)\\(?:<(epsilon d e)>\\)*"))))
-(ert-deftest rx-seq ()
- ;; Test zero-argument `seq'.
- (should (equal (rx (seq)) "")))
-
-(defmacro rx-tests--match (regexp string &optional match)
- (macroexp-let2 nil strexp string
- `(ert-info ((format "Matching %S to %S" ',regexp ,strexp))
- (should (string-match ,regexp ,strexp))
- ,@(when match
- `((should (equal (match-string 0 ,strexp) ,match)))))))
-
-(ert-deftest rx-nonstring-expr ()
- (let ((bee "b")
- (vowel "[aeiou]"))
- (rx-tests--match (rx "a" (literal bee) "c") "abc")
- (rx-tests--match (rx "a" (regexp bee) "c") "abc")
- (rx-tests--match (rx "a" (or (regexp bee) "xy") "c") "abc")
- (rx-tests--match (rx "a" (or "xy" (regexp bee)) "c") "abc")
- (should-not (string-match (rx (or (regexp bee) "xy")) ""))
- (rx-tests--match (rx "a" (= 3 (regexp bee)) "c") "abbbc")
- (rx-tests--match (rx "x" (= 3 (regexp vowel)) "z") "xeoez")
- (should-not (string-match (rx "x" (= 3 (regexp vowel)) "z") "xe[]z"))
- (rx-tests--match (rx "x" (= 3 (literal vowel)) "z")
- "x[aeiou][aeiou][aeiou]z")
- (rx-tests--match (rx "x" (repeat 1 (regexp vowel)) "z") "xaz")
- (rx-tests--match (rx "x" (repeat 1 2 (regexp vowel)) "z") "xaz")
- (rx-tests--match (rx "x" (repeat 1 2 (regexp vowel)) "z") "xauz")
- (rx-tests--match (rx "x" (>= 1 (regexp vowel)) "z") "xaiiz")
- (rx-tests--match (rx "x" (** 1 2 (regexp vowel)) "z") "xaiz")
- (rx-tests--match (rx "x" (group (regexp vowel)) "z") "xaz")
- (rx-tests--match (rx "x" (group-n 1 (regexp vowel)) "z") "xaz")
- (rx-tests--match (rx "x" (? (regexp vowel)) "z") "xz")))
-
-(ert-deftest rx-nonstring-expr-non-greedy ()
- "`rx's greediness can't affect runtime regexp parts."
- (let ((ad-min "[ad]*?")
- (ad-max "[ad]*")
- (ad "[ad]"))
- (rx-tests--match (rx "c" (regexp ad-min) "a") "cdaaada" "cda")
- (rx-tests--match (rx "c" (regexp ad-max) "a") "cdaaada" "cdaaada")
- (rx-tests--match (rx "c" (minimal-match (regexp ad-max)) "a") "cdaaada" "cdaaada")
- (rx-tests--match (rx "c" (maximal-match (regexp ad-min)) "a") "cdaaada" "cda")
- (rx-tests--match (rx "c" (minimal-match (0+ (regexp ad))) "a") "cdaaada" "cda")
- (rx-tests--match (rx "c" (maximal-match (0+ (regexp ad))) "a") "cdaaada" "cdaaada")))
-
-(ert-deftest rx-to-string-lisp-forms ()
- (rx-tests--match (rx-to-string '(seq "a" (literal "b") "c")) "abc")
- (rx-tests--match (rx-to-string '(seq "a" (regexp "b") "c")) "abc"))
(provide 'rx-tests)
-;; rx-tests.el ends here.
--
2.21.0 (Apple Git-122)
[-- Attachment #3: 0002-Add-rx-extension-mechanism.patch --]
[-- Type: application/octet-stream, Size: 28290 bytes --]
From f1b775f200b127c861ebdb0fa78110948d9e81f5 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Mattias=20Engdeg=C3=A5rd?= <mattiase@acm.org>
Date: Mon, 2 Sep 2019 16:07:23 +0200
Subject: [PATCH 2/2] Add rx extension mechanism
Add a built-in set of extension macros: `rx-define', `rx-let' and
`rx-let-eval'.
* lisp/emacs-lisp/rx.el (rx-constituents, rx-to-string): Doc updates.
(rx--builtin-symbols, rx--builtin-names, rx--local-definitions)
(rx--lookup-def, rx--substitute, rx--expand-template)
(rx--make-binding, rx--make-named-binding, rx--extend-local-defs)
(rx-let-eval, rx-let, rx-define): New.
(rx--translate-symbol, rx--translate-form): Use extensions if any.
(rx): Use local definitions.
* test/lisp/emacs-lisp/rx-tests.el (rx-let, rx-define)
(rx-to-string-define, rx-let-define, rx-let-eval): New.
* etc/NEWS (Changes in Specialized Modes and Packages):
* doc/lispref/searching.texi (Rx Notation, Rx Functions, Extending Rx):
Add node about rx extensions.
---
doc/lispref/searching.texi | 157 ++++++++++++++++
etc/NEWS | 4 +
lisp/emacs-lisp/rx.el | 299 ++++++++++++++++++++++++++++---
test/lisp/emacs-lisp/rx-tests.el | 98 ++++++++++
4 files changed, 538 insertions(+), 20 deletions(-)
diff --git a/doc/lispref/searching.texi b/doc/lispref/searching.texi
index 21b1f7b68b..015871fab0 100644
--- a/doc/lispref/searching.texi
+++ b/doc/lispref/searching.texi
@@ -1037,6 +1037,7 @@ Rx Notation
@menu
* Rx Constructs:: Constructs valid in rx forms.
* Rx Functions:: Functions and macros that use rx forms.
+* Extending Rx:: How to define your own rx forms.
@end menu
@node Rx Constructs
@@ -1524,6 +1525,162 @@ Rx Functions
The @code{pcase} macro can use @code{rx} expressions as patterns
directly; @pxref{rx in pcase}.
+
+For mechanisms to add user-defined extensions to the @code{rx}
+notation, @pxref{Extending Rx}.
+
+@node Extending Rx
+@subsubsection Defining new @code{rx} forms
+
+The @code{rx} notation can be extended by defining new symbols and
+parametrised forms in terms of other @code{rx} expressions. This is
+handy for sharing parts between several regexps, and for making
+complex ones easier to build and understand by putting them together
+from smaller pieces.
+
+For example, you could define @code{name} to mean
+@code{(one-or-more letter)}, and @code{(quoted @var{x})} to mean
+@code{(seq ?' @var{x} ?')} for any @var{x}. These forms could then be
+used in @code{rx} expressions like any other: @code{(rx (quoted name))}
+would match a nonempty sequence of letters inside single quotes.
+
+The Lisp macros below provide different ways of binding names to
+definitions. Common to all of them are the following rules:
+
+@itemize
+@item
+Built-in @code{rx} forms, like @code{digit} and @code{group}, cannot
+be redefined.
+
+@item
+The definitions live in a name space of their own, separate from that
+of Lisp variables. There is thus no need to attach a suffix like
+@code{-regexp} to names; they cannot collide with anything else.
+
+@item
+Definitions cannot refer to themselves recursively, directly or
+indirectly. If you find yourself needing this, you want a parser, not
+a regular expression.
+
+@item
+Definitions are only ever expanded in calls to @code{rx} or
+@code{rx-to-string}, not merely by their presence in definition
+macros. This means that the order of definitions doesn't matter, even
+when they refer to each other, and that syntax errors only show up
+when they are used, not when they are defined.
+
+@item
+User-defined forms are allowed wherever arbitrary @code{rx}
+expressions are expected; for example, in the body of a
+@code{zero-or-one} form, but not inside @code{any} or @code{category}
+forms.
+@end itemize
+
+@defmac rx-define name [arglist] rx-form
+Define @var{name} globally in all subsequent calls to @code{rx} and
+@code{rx-to-string}. If @var{arglist} is absent, then @var{name} is
+defined as a plain symbol to be replaced with @var{rx-form}. Example:
+
+@example
+@group
+(rx-define haskell-comment (seq "--" (zero-or-more nonl)))
+(rx haskell-comment)
+ @result{} "--.*"
+@end group
+@end example
+
+If @var{arglist} is present, it must be a list of zero or more
+argument names, and @var{name} is then defined as a parametrised form.
+When used in an @code{rx} expression as @code{(@var{name} @var{arg}@dots{})},
+each @var{arg} will replace the corresponding argument name inside
+@var{rx-form}.
+
+@var{arglist} may end in @code{&rest} and one final argument name,
+denoting a rest parameter. The rest parameter will expand to all
+extra actual argument values not matched by any other parameter in
+@var{arglist}, spliced into @var{rx-form} where it occurs. Example:
+
+@example
+@group
+(rx-define moan (x y &rest r) (seq x (one-or-more y) r "!"))
+(rx (moan "MOO" "A" "MEE" "OW"))
+ @result{} "MOOA+MEEOW!"
+@end group
+@end example
+
+Since the definition is global, it is recommended to give @var{name} a
+package prefix to avoid name clashes with definitions elsewhere, as is
+usual when naming non-local variables and functions.
+@end defmac
+
+@defmac rx-let (bindings@dots{}) body@dots{}
+Make the @code{rx} definitions in @var{bindings} available locally for
+@code{rx} macro invocations in @var{body}, which is then evaluated.
+
+Each element of @var{bindings} is on the form
+@w{@code{(@var{name} [@var{arglist}] @var{rx-form})}}, where the parts
+have the same meaning as in @code{rx-define} above. Example:
+
+@example
+@group
+(rx-let ((comma-separated (item) (seq item (0+ "," item)))
+ (number (1+ digit))
+ (numbers (comma-separated number)))
+ (re-search-forward (rx "(" numbers ")")))
+@end group
+@end example
+
+The definitions are only available during the macro-expansion of
+@var{body}, and are thus not present during execution of compiled
+code.
+
+@code{rx-let} can be used not only inside a function, but also at top
+level to include global variable and function definitions that need
+to share a common set of @code{rx} forms. Since the names are local
+inside @var{body}, there is no need for any package prefixes.
+Example:
+
+@example
+@group
+(rx-let ((phone-number (seq (opt ?+) (1+ (any digit ?-)))))
+ (defun find-next-phone-number ()
+ (re-search-forward (rx phone-number)))
+ (defun phone-number-p (string)
+ (string-match-p (rx bos phone-number eos) string)))
+@end group
+@end example
+
+The scope of the @code{rx-let} bindings is lexical, which means that
+they are not visible outside @var{body} itself, even in functions
+called from @var{body}.
+@end defmac
+
+@defmac rx-let-eval bindings body@dots{}
+Evaluate @var{bindings} to a list of bindings as in @code{rx-let},
+and evaluate @var{body} with those bindings in effect for calls
+to @code{rx-to-string}.
+
+This macro is similar to @code{rx-let}, except that the @var{bindings}
+argument is evaluated (and thus needs to be quoted if it is a list
+literal), and the definitions are substituted at run time, which is
+required for @code{rx-to-string} to work. Example:
+
+@example
+@group
+(rx-let-eval
+ '((ponder (x) (seq "Where have all the " x " gone?")))
+ (looking-at (rx-to-string
+ '(ponder (or "flowers" "young girls"
+ "left socks")))))
+@end group
+@end example
+
+Another difference from @code{rx-let} is that the @var{bindings} are
+dynamically scoped, and thus also available in functions called from
+@var{body}. However, they are not visible inside functions defined in
+@var{body}.
+@end defmac
+
@end ifnottex
@node Regexp Functions
diff --git a/etc/NEWS b/etc/NEWS
index 50956f4082..3f7d4894df 100644
--- a/etc/NEWS
+++ b/etc/NEWS
@@ -1725,6 +1725,10 @@ This also works for their aliases: '|' for 'or'; ':', 'and' and
In this case, 'rx' will generate code which produces a regexp string
at run time, instead of a constant string.
+---
+*** New rx extension mechanism: 'rx-define', 'rx-let', 'rx-let-eval'.
+These macros add new forms to the rx notation.
+
** Frames
+++
diff --git a/lisp/emacs-lisp/rx.el b/lisp/emacs-lisp/rx.el
index 9b3419e1c8..a192ed1ad2 100644
--- a/lisp/emacs-lisp/rx.el
+++ b/lisp/emacs-lisp/rx.el
@@ -97,6 +97,7 @@ rx--char-classes
(defvar rx-constituents nil
"Alist of old-style rx extensions, for compatibility.
+For new code, use `rx-define', `rx-let' or `rx-let-eval'.
Each element is (SYMBOL . DEF).
@@ -113,6 +114,17 @@ rx-constituents
If PRED is non-nil, it is a predicate that all actual arguments must
satisfy.")
+(defvar rx--local-definitions nil
+ "Alist of dynamic local rx definitions.
+Each entry is:
+ (NAME DEF) -- NAME is an rx symbol defined as the rx form DEF.
+ (NAME ARGS DEF) -- NAME is an rx form with arglist ARGS, defined
+ as the rx form DEF (which can contain members of ARGS).")
+
+(defsubst rx--lookup-def (name)
+ (or (cdr (assq name rx--local-definitions))
+ (get name 'rx-definition)))
+
;; TODO: Additions to consider:
;; - A better name for `anything', like `any-char' or `anychar'.
;; - A name for (or), maybe `unmatchable'.
@@ -144,6 +156,12 @@ rx--translate-symbol
((let ((class (cdr (assq sym rx--char-classes))))
(and class (cons (list (concat "[[:" (symbol-name class) ":]]")) t))))
+ ((let ((definition (rx--lookup-def sym)))
+ (and definition
+ (if (cdr definition)
+ (error "Not an `rx' symbol definition: %s" sym)
+ (rx--translate (nth 0 definition))))))
+
;; For compatibility with old rx.
((let ((entry (assq sym rx-constituents)))
(and (progn
@@ -310,6 +328,19 @@ rx--condense-intervals
(setq tail d)))
intervals))
+;; FIXME: Consider expanding definitions inside (any ...) and (not ...),
+;; and perhaps allow (any ...) inside (any ...).
+;; It would be benefit composability (build a character alternative by pieces)
+;; and be handy for obtaining the complement of a defined set of
+;; characters. (See, for example, python.el:421, `not-simple-operator'.)
+;; (Expansion in other non-rx positions is probably not a good idea:
+;; syntax, category, backref, and the integer parameters of group-n,
+;; =, >=, **, repeat)
+;; Similar effect could be attained by ensuring that
+;; (or (any X) (any Y)) -> (any X Y), and find a way to compose negative
+;; sets. `and' is taken, but we could add
+;; (intersection (not (any X)) (not (any Y))) -> (not (any X Y)).
+
(defun rx--translate-any (negated body)
"Translate an (any ...) construct. Return (REGEXP . PRECEDENCE).
If NEGATED, negate the sense."
@@ -712,6 +743,94 @@ rx--translate-compat-form
(error "The `%s' form did not expand to a string" (car form)))
(cons (list regexp) nil))))
+(defun rx--substitute (bindings form)
+ "Substitute BINDINGS in FORM. BINDINGS is an alist of (NAME . VALUES)
+where VALUES is a list to splice into FORM wherever NAME occurs.
+Return the substitution result wrapped in a list, since a single value
+can expand to any number of values."
+ (cond ((symbolp form)
+ (let ((binding (assq form bindings)))
+ (if binding
+ (cdr binding)
+ (list form))))
+ ((consp form)
+ (if (listp (cdr form))
+ ;; Proper list. We substitute variables even in the head
+ ;; position -- who knows, might be handy one day.
+ (list (mapcan (lambda (x) (copy-sequence
+ (rx--substitute bindings x)))
+ form))
+ ;; Cons pair (presumably an interval).
+ (let ((first (rx--substitute bindings (car form)))
+ (second (rx--substitute bindings (cdr form))))
+ (if (and first (not (cdr first))
+ second (not (cdr second)))
+ (list (cons (car first) (car second)))
+ (error
+ "Cannot substitute a &rest parameter into a dotted pair")))))
+ (t (list form))))
+
+;; FIXME: Consider adding extensions in Lisp macro style, where
+;; arguments are passed unevaluated to code that returns the rx form
+;; to use. Example:
+;;
+;; (rx-let ((radix-digit (radix)
+;; :lisp (list 'any (cons ?0 (+ ?0 (eval radix) -1)))))
+;; (rx (radix-digit (+ 5 3))))
+;; =>
+;; "[0-7]"
+;;
+;; While this would permit more powerful extensions, it's unclear just
+;; how often they would be used in practice. Let's wait until there is
+;; demand for it.
+
+;; FIXME: An alternative binding syntax would be
+;;
+;; (NAME RXs...)
+;; and
+;; ((NAME ARGS...) RXs...)
+;;
+;; which would have two minor advantages: multiple RXs with implicit
+;; `seq' in the definition, and the arglist is no longer an optional
+;; element in the middle of the list. On the other hand, it's less
+;; like traditional lisp arglist constructs (defun, defmacro).
+;; Since it's a Scheme-like syntax, &rest parameters could be done using
+;; dotted lists:
+;; (rx-let (((name arg1 arg2 . rest) ...definition...)) ...)
+
+(defun rx--expand-template (op values arglist template)
+ "Return TEMPLATE with variables in ARGLIST replaced with VALUES."
+ (let ((bindings nil)
+ (value-tail values)
+ (formals arglist))
+ (while formals
+ (pcase (car formals)
+ ('&rest
+ (unless (cdr formals)
+ (error
+ "Expanding rx def `%s': missing &rest parameter name" op))
+ (push (cons (cadr formals) value-tail) bindings)
+ (setq formals nil)
+ (setq value-tail nil))
+ (name
+ (unless value-tail
+ (error
+ "Expanding rx def `%s': too few arguments (got %d, need %s%d)"
+ op (length values)
+ (if (memq '&rest arglist) "at least " "")
+ (- (length arglist) (length (memq '&rest arglist)))))
+ (push (cons name (list (car value-tail))) bindings)
+ (setq value-tail (cdr value-tail))))
+ (setq formals (cdr formals)))
+ (when value-tail
+ (error
+ "Expanding rx def `%s': too many arguments (got %d, need %d)"
+ op (length values) (length arglist)))
+ (let ((subst (rx--substitute bindings template)))
+ (if (and subst (not (cdr subst)))
+ (car subst)
+ (error "Expanding rx def `%s': must result in a single value" op)))))
+
(defun rx--translate-form (form)
"Translate an rx form (list structure). Return (REGEXP . PRECEDENCE)."
(let ((body (cdr form)))
@@ -757,24 +876,29 @@ rx--translate-form
(op
(unless (symbolp op)
(error "Bad rx operator `%S'" op))
+ (let ((definition (rx--lookup-def op)))
+ (if definition
+ (if (cdr definition)
+ (rx--translate
+ (rx--expand-template
+ op body (nth 0 definition) (nth 1 definition)))
+ (error "Not an `rx' form definition: %s" op))
+
+ ;; For compatibility with old rx.
+ (let ((entry (assq op rx-constituents)))
+ (if (progn
+ (while (and entry (not (consp (cdr entry))))
+ (setq entry
+ (if (symbolp (cdr entry))
+ ;; Alias for another entry.
+ (assq (cdr entry) rx-constituents)
+ ;; Wrong type, try further down the list.
+ (assq (car entry)
+ (cdr (memq entry rx-constituents))))))
+ entry)
+ (rx--translate-compat-form (cdr entry) form)
+ (error "Unknown rx form `%s'" op)))))))))
- ;; For compatibility with old rx.
- (let ((entry (assq op rx-constituents)))
- (if (progn
- (while (and entry (not (consp (cdr entry))))
- (setq entry
- (if (symbolp (cdr entry))
- ;; Alias for another entry.
- (assq (cdr entry) rx-constituents)
- ;; Wrong type, try further down the list.
- (assq (car entry)
- (cdr (memq entry rx-constituents))))))
- entry)
- (rx--translate-compat-form (cdr entry) form)
- (error "Unknown rx form `%s'" op)))))))
-
-;; Defined here rather than in re-builder to lower the odds that it
-;; will be kept in sync with changes.
(defconst rx--builtin-forms
'(seq sequence : and or | any in char not-char not
repeat = >= **
@@ -786,7 +910,21 @@ rx--builtin-forms
group submatch group-n submatch-n backref
syntax not-syntax category
literal eval regexp regex)
- "List of built-in rx forms. For use in re-builder only.")
+ "List of built-in rx function-like symbols.")
+
+(defconst rx--builtin-symbols
+ (append '(nonl not-newline any anything
+ bol eol line-start line-end
+ bos eos string-start string-end
+ bow eow word-start word-end
+ symbol-start symbol-end
+ point word-boundary not-word-boundary not-wordchar)
+ (mapcar #'car rx--char-classes))
+ "List of built-in rx variable-like symbols.")
+
+(defconst rx--builtin-names
+ (append rx--builtin-forms rx--builtin-symbols)
+ "List of built-in rx names. These cannot be redefined by the user.")
(defun rx--translate (item)
"Translate the rx-expression ITEM. Return (REGEXP . PRECEDENCE)."
@@ -810,7 +948,9 @@ rx-to-string
The arguments to `literal' and `regexp' forms inside FORM must be
constant strings.
If NO-GROUP is non-nil, don't bracket the result in a non-capturing
-group."
+group.
+
+For extending the `rx' notation in FORM, use `rx-define' or `rx-let-eval'."
(let* ((item (rx--translate form))
(exprs (if no-group
(car item)
@@ -939,14 +1079,133 @@ rx
(regexp EXPR) Match the string regexp from evaluating EXPR at run time.
(eval EXPR) Match the rx sexp from evaluating EXPR at compile time.
+Additional constructs can be defined using `rx-define' and `rx-let',
+which see.
+
\(fn REGEXPS...)"
- (rx--to-expr (cons 'seq regexps)))
+ ;; Retrieve local definitions from the macroexpansion environment.
+ ;; (It's unclear whether the previous value of `rx--local-definitions'
+ ;; should be included, and if so, in which order.)
+ (let ((rx--local-definitions
+ (cdr (assq :rx-locals macroexpand-all-environment))))
+ (rx--to-expr (cons 'seq regexps))))
+
+(defun rx--make-binding (name tail)
+ "Make a definitions entry out of TAIL.
+TAIL is on the form ([ARGLIST] DEFINITION)."
+ (unless (symbolp name)
+ (error "Bad `rx' definition name: %S" name))
+ ;; FIXME: Consider using a hash table or symbol property, for speed.
+ (when (memq name rx--builtin-names)
+ (error "Cannot redefine built-in rx name `%s'" name))
+ (pcase tail
+ (`(,def)
+ (list def))
+ (`(,args ,def)
+ (unless (and (listp args) (rx--every #'symbolp args))
+ (error "Bad argument list for `rx' definition %s: %S" name args))
+ (list args def))
+ (_ (error "Bad `rx' definition of %s: %S" name tail))))
+
+(defun rx--make-named-binding (bindspec)
+ "Make a definitions entry out of BINDSPEC.
+BINDSPEC is on the form (NAME [ARGLIST] DEFINITION)."
+ (unless (consp bindspec)
+ (error "Bad `rx-let' binding: %S" bindspec))
+ (cons (car bindspec)
+ (rx--make-binding (car bindspec) (cdr bindspec))))
+
+(defun rx--extend-local-defs (bindspecs)
+ (append (mapcar #'rx--make-named-binding bindspecs)
+ rx--local-definitions))
+;;;###autoload
+(defmacro rx-let-eval (bindings &rest body)
+ "Evaluate BODY with local BINDINGS for `rx-to-string'.
+BINDINGS, after evaluation, is a list of definitions each on the form
+(NAME [(ARGS...)] RX), in effect for calls to `rx-to-string'
+in BODY.
+
+For bindings without an ARGS list, NAME is defined as an alias
+for the `rx' expression RX. Where ARGS is supplied, NAME is
+defined as an `rx' form with ARGS as argument list. The
+parameters are bound from the values in the (NAME ...) form and
+are substituted in RX. ARGS can contain `&rest' parameters,
+whose values are spliced into RX where the parameter name occurs.
+
+Any previous definitions with the same names are shadowed during
+the expansion of BODY only.
+For extensions when using the `rx' macro, use `rx-let'.
+To make global rx extensions, use `rx-define'.
+For more details, see Info node `(elisp) Extending Rx'.
+
+\(fn BINDINGS BODY...)"
+ (declare (indent 1) (debug (form body)))
+ ;; FIXME: this way, `rx--extend-local-defs' may need to be autoloaded.
+ `(let ((rx--local-definitions (rx--extend-local-defs ,bindings)))
+ ,@body))
+
+;;;###autoload
+(defmacro rx-let (bindings &rest body)
+ "Evaluate BODY with local BINDINGS for `rx'.
+BINDINGS is an unevaluated list of bindings each on the form
+(NAME [(ARGS...)] RX).
+They are bound lexically and are available in `rx' expressions in
+BODY only.
+
+For bindings without an ARGS list, NAME is defined as an alias
+for the `rx' expression RX. Where ARGS is supplied, NAME is
+defined as an `rx' form with ARGS as argument list. The
+parameters are bound from the values in the (NAME ...) form and
+are substituted in RX. ARGS can contain `&rest' parameters,
+whose values are spliced into RX where the parameter name occurs.
+
+Any previous definitions with the same names are shadowed during
+the expansion of BODY only.
+For local extensions to `rx-to-string', use `rx-let-eval'.
+To make global rx extensions, use `rx-define'.
+For more details, see Info node `(elisp) Extending Rx'.
+
+\(fn BINDINGS BODY...)"
+ (declare (indent 1) (debug (sexp body)))
+ (let ((prev-locals (cdr (assq :rx-locals macroexpand-all-environment)))
+ (new-locals (mapcar #'rx--make-named-binding bindings)))
+ (macroexpand-all (cons 'progn body)
+ (cons (cons :rx-locals (append new-locals prev-locals))
+ macroexpand-all-environment))))
+
+;;;###autoload
+(defmacro rx-define (name &rest definition)
+ "Define NAME as a global `rx' definition.
+If the ARGS list is omitted, define NAME as an alias for the `rx'
+expression RX.
+
+If the ARGS list is supplied, define NAME as an `rx' form with
+ARGS as argument list. The parameters are bound from the values
+in the (NAME ...) form and are substituted in RX.
+ARGS can contain `&rest' parameters, whose values are spliced
+into RX where the parameter name occurs.
+
+Any previous global definition of NAME is overwritten with the new one.
+To make local rx extensions, use `rx-let' for `rx',
+`rx-let-eval' for `rx-to-string'.
+For more details, see Info node `(elisp) Extending Rx'.
+
+\(fn NAME [(ARGS...)] RX)"
+ (declare (indent 1))
+ `(eval-and-compile
+ (put ',name 'rx-definition ',(rx--make-binding name definition))
+ ',name))
;; During `rx--pcase-transform', list of defined variables in right-to-left
;; order.
(defvar rx--pcase-vars)
+;; FIXME: The rewriting strategy for pcase works so-so with extensions;
+;; definitions cannot expand to `let' or named `backref'. If this ever
+;; becomes a problem, we can handle those forms in the ordinary parser,
+;; using a dynamic variable for activating the augmented forms.
+
(defun rx--pcase-transform (rx)
"Transform RX, an rx-expression augmented with `let' and named `backref',
into a plain rx-expression, collecting names into `rx--pcase-vars'."
diff --git a/test/lisp/emacs-lisp/rx-tests.el b/test/lisp/emacs-lisp/rx-tests.el
index fec046dd99..11de4771de 100644
--- a/test/lisp/emacs-lisp/rx-tests.el
+++ b/test/lisp/emacs-lisp/rx-tests.el
@@ -303,6 +303,104 @@ rx-to-string
(should (equal (rx-to-string '(or nonl "\nx") t)
".\\|\nx")))
+(ert-deftest rx-let ()
+ (rx-let ((beta gamma)
+ (gamma delta)
+ (delta (+ digit))
+ (epsilon (or gamma nonl)))
+ (should (equal (rx bol delta epsilon)
+ "^[[:digit:]]+\\(?:[[:digit:]]+\\|.\\)")))
+ (rx-let ((p () point)
+ (separated (x sep) (seq x (* sep x)))
+ (comma-separated (x) (separated x ","))
+ (semi-separated (x) (separated x ";"))
+ (matrix (v) (semi-separated (comma-separated v))))
+ (should (equal (rx (p) (matrix (+ "a")) eos)
+ "\\=a+\\(?:,a+\\)*\\(?:;a+\\(?:,a+\\)*\\)*\\'")))
+ (rx-let ((b bol)
+ (z "B")
+ (three (x) (= 3 x)))
+ (rx-let ((two (x) (seq x x))
+ (z "A")
+ (e eol))
+ (should (equal (rx b (two (three z)) e)
+ "^A\\{3\\}A\\{3\\}$"))))
+ (rx-let ((f (a b &rest r) (seq "<" a ";" b ":" r ">")))
+ (should (equal (rx bol (f ?x ?y) ?! (f ?u ?v ?w) ?! (f ?k ?l ?m ?n) eol)
+ "^<x;y:>!<u;v:w>!<k;l:mn>$")))
+
+ ;; Rest parameters are expanded by splicing.
+ (rx-let ((f (&rest r) (or bol r eol)))
+ (should (equal (rx (f "ab" nonl))
+ "^\\|ab\\|.\\|$")))
+
+ ;; Substitution is done in number positions.
+ (rx-let ((stars (n) (= n ?*)))
+ (should (equal (rx (stars 4))
+ "\\*\\{4\\}")))
+
+ ;; Substitution is done inside dotted pairs.
+ (rx-let ((f (x y z) (any x (y . z))))
+ (should (equal (rx (f ?* ?a ?t))
+ "[*a-t]")))
+
+ ;; Substitution is done in the head position of forms.
+ (rx-let ((f (x) (x "a")))
+ (should (equal (rx (f +))
+ "a+"))))
+
+(ert-deftest rx-define ()
+ (rx-define rx--a (seq "x" (opt "y")))
+ (should (equal (rx bol rx--a eol)
+ "^xy?$"))
+ (rx-define rx--c (lb rb &rest stuff) (seq lb stuff rb))
+ (should (equal (rx bol (rx--c "<" ">" rx--a nonl) eol)
+ "^<xy?.>$"))
+ (rx-define rx--b (* rx--a))
+ (should (equal (rx rx--b)
+ "\\(?:xy?\\)*"))
+ (rx-define rx--a "z")
+ (should (equal (rx rx--b)
+ "z*")))
+
+(defun rx--test-rx-to-string-define ()
+ ;; `rx-define' won't expand to code inside `ert-deftest' since we use
+ ;; `eval-and-compile'. Put it into a defun as a workaround.
+ (rx-define rx--d "Q")
+ (rx-to-string '(seq bol rx--d) t))
+
+(ert-deftest rx-to-string-define ()
+ "Check that `rx-to-string' uses definitions made by `rx-define'."
+ (should (equal (rx--test-rx-to-string-define)
+ "^Q")))
+
+(ert-deftest rx-let-define ()
+ "Test interaction between `rx-let' and `rx-define'."
+ (rx-define rx--e "one")
+ (rx-define rx--f "eins")
+ (rx-let ((rx--e "two"))
+ (should (equal (rx rx--e nonl rx--f) "two.eins"))
+ (rx-define rx--e "three")
+ (should (equal (rx rx--e) "two"))
+ (rx-define rx--f "zwei")
+ (should (equal (rx rx--f) "zwei")))
+ (should (equal (rx rx--e nonl rx--f) "three.zwei")))
+
+(ert-deftest rx-let-eval ()
+ (rx-let-eval '((a (* digit))
+ (f (x &rest r) (seq x nonl r)))
+ (should (equal (rx-to-string '(seq a (f bow a ?b)) t)
+ "[[:digit:]]*\\<.[[:digit:]]*b"))))
+
+(ert-deftest rx-redefine-builtin ()
+ (should-error (rx-define sequence () "x"))
+ (should-error (rx-define sequence "x"))
+ (should-error (rx-define nonl () "x"))
+ (should-error (rx-define nonl "x"))
+ (should-error (rx-let ((punctuation () "x")) nil))
+ (should-error (rx-let ((punctuation "x")) nil))
+ (should-error (rx-let-eval '((not-char () "x")) nil))
+ (should-error (rx-let-eval '((not-char "x")) nil)))
(ert-deftest rx-constituents ()
(let ((rx-constituents
--
2.21.0 (Apple Git-122)
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-- links below jump to the message on this page --
2019-09-17 12:49 bug#37440: [PATCH] New rx implementation with extension constructs Mattias Engdegård
2019-09-17 17:47 ` Paul Eggert
2019-09-24 17:55 ` Paul Eggert
2019-09-25 12:33 ` Mattias Engdegård
2019-09-25 21:30 ` Paul Eggert
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