Re: [PATCH] sequence manipulation functions

[Nicolas Petton <petton.nicolas@gmail.com>]

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There was an error in my previous patch.


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diff --git a/lisp/ChangeLog b/lisp/ChangeLog
index 35141b6..b77dd06 100644
--- a/lisp/ChangeLog
+++ b/lisp/ChangeLog
@@ -1,3 +1,7 @@
+2014-11-24  Nicolas Petton <petton.nicolas@gmail.com>
+
+	* emacs-lisp/seq.el: New file.
+
 2014-11-24  Stefan Monnier  <monnier@iro.umontreal.ca>
 
 	* vc/vc-hooks.el (vc-state-base-face): Don't override
diff --git a/lisp/emacs-lisp/seq.el b/lisp/emacs-lisp/seq.el
new file mode 100644
index 0000000..af90c1e
--- /dev/null
+++ b/lisp/emacs-lisp/seq.el
@@ -0,0 +1,222 @@
+;;; seq.el --- Sequence manipulation functions  -*- lexical-binding: t -*-
+
+;; Copyright (C) 2014 Free Software Foundation, Inc.
+
+;; Author: Nicolas Petton <petton.nicolas@gmail.com>
+;; Keywords: sequences
+
+;; Maintainer: emacs-devel@gnu.org
+
+;; This file is part of GNU Emacs.
+
+;; GNU Emacs is free software: you can redistribute it and/or modify
+;; it under the terms of the GNU General Public License as published by
+;; the Free Software Foundation, either version 3 of the License, or
+;; (at your option) any later version.
+
+;; GNU Emacs is distributed in the hope that it will be useful,
+;; but WITHOUT ANY WARRANTY; without even the implied warranty of
+;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+;; GNU General Public License for more details.
+
+;; You should have received a copy of the GNU General Public License
+;; along with GNU Emacs.  If not, see <http://www.gnu.org/licenses/>.
+
+;;; Commentary:
+
+;; Sequence-manipulation functions that complement basic functions
+;; provided by subr.el.
+;;
+;; All functions are prefixed with "seq-".
+;;
+;; All provided functions work on lists, strings and vectors.
+;;
+;; Functions taking a predicate or a function iterating over the
+;; sequence as argument take the function as their first argument and
+;; the sequence as their second argument.  All other functions take
+;; the sequence as their first argument.
+;;
+;; All functions are tested in test/automated/seq-tests.el
+
+;;; Code:
+
+(defmacro seq-doseq (spec &rest body)
+  "Loop over a sequence.
+Similar to `dolist' but can be applied lists, strings and vectors.
+
+Evaluate BODY with VAR bound to each element of SEQ, in turn.
+Then evaluate RESULT to get return value, default nil.
+
+\(fn (VAR SEQ [RESULT]) BODY...)"
+  (declare (indent 1) (debug ((symbolp form &optional form) body)))
+  (let ((is-list (make-symbol "is-list"))
+        (seq (make-symbol "seq"))
+        (index (make-symbol "index")))
+    `(let* ((,seq ,(cadr spec))
+            (,is-list (listp ,seq))
+            (,index (if ,is-list ,seq 0)))
+       (while (if ,is-list
+                  (consp ,index)
+                (< ,index (seq-length ,seq)))
+         (let ((,(car spec) (if ,is-list
+                                (car ,index)
+                              (seq-elt ,seq ,index))))
+           ,@body
+           (setq ,index (if ,is-list
+                            (cdr ,index)
+                          (+ ,index 1)))))
+       ,@(if (cddr spec)
+             `((setq ,(car spec) nil) ,@(cddr spec))))))
+
+(defun seq-drop (seq n)
+  "Return a subsequence of SEQ without its first N elements.
+The result is a sequence of the same type as SEQ."
+  (let ((length (seq-length seq)))
+    (seq-subseq seq (min n length) length)))
+
+(defun seq-take (seq n)
+  "Return a subsequence of SEQ with its first N elements.
+The result is a sequence of the same type as SEQ."
+  (seq-subseq seq 0 (min n (seq-length seq))))
+
+(defun seq-drop-while (pred seq)
+  "Return a sequence, from the first element for which (PRED element) is nil, of SEQ.
+The result is a sequence of the same type as SEQ."
+  (let ((n 0))
+    (while (and (< n (seq-length seq))
+                (funcall pred (seq-elt seq n)))
+      (setq n (+ 1 n)))
+    (seq-drop seq n)))
+
+(defun seq-take-while (pred seq)
+  "Return a sequence of the successive elements for which (PRED element) is non-nil in SEQ.
+The result is a sequence of the same type as SEQ."
+  (let ((n 0))
+    (while (and (< n (seq-length seq))
+                (funcall pred (seq-elt seq n)))
+      (setq n (+ 1 n)))
+    (seq-take seq n)))
+
+(defun seq-filter (pred seq)
+  "Return a list of all the elements for which (PRED element) is non-nil in SEQ."
+  (let ((exclude (make-symbol "exclude")))
+    (delq exclude (seq-map (lambda (elt)
+                             (if (funcall pred elt)
+                                 elt
+                               exclude))
+                           seq))))
+
+(defun seq-remove (pred seq)
+  "Return a list of all the elements for which (PRED element) is nil in SEQ."
+  (seq-filter (lambda (elt) (not (funcall pred elt)))
+              seq))
+
+(defun seq-reduce (function seq initial-value)
+  "Reduce the function FUNCTION across SEQ, starting with INITIAL-VALUE.
+
+Return the result of applying FUNCTION to INITIAL-VALUE and the
+first element of SEQ, then applying FUNCTION to that result and
+the second element of SEQ, then to that result and the third
+element of SEQ, etc.
+
+If SEQ is empty, return INITIAL-VALUE and FUNCTION is not called."
+  (if (seq-empty-p seq)
+      initial-value
+    (let ((acc initial-value))
+      (seq-doseq (elt seq)
+        (setq acc (funcall function acc elt)))
+      acc)))
+
+(defun seq-some-p (pred seq)
+  "Return any element for which (PRED element) is non-nil in SEQ, nil otherwise."
+  (catch 'seq--break
+    (seq-doseq (elt seq)
+      (when (funcall pred elt)
+        (throw 'seq--break elt)))
+    nil))
+
+(defun seq-every-p (pred seq)
+  "Return non-nil if (PRED element) is non-nil for all elements of the sequence SEQ."
+  (catch 'seq--break
+    (seq-doseq (elt seq)
+      (or (funcall pred elt)
+          (throw 'seq--break nil)))
+    t))
+
+(defun seq-count (pred seq)
+  "Return the number of elements for which (PRED element) in non-nil in seq."
+  (let ((count 0))
+    (seq-doseq (elt seq)
+      (when (funcall pred elt)
+        (setq count (+ 1 count))))
+    count))
+
+(defun seq-empty-p (seq)
+  "Return non-nil if the sequence SEQ is empty, nil otherwise."
+  (= 0 (seq-length seq)))
+
+(defun seq-sort (pred seq)
+  "Return a sorted sequence comparing using PRED the elements of SEQ.
+The result is a sequence of the same type as SEQ."
+  (if (listp seq)
+      (sort (seq-copy seq) pred)
+    (let ((result (seq-sort pred (append seq nil))))
+      (cond ((stringp seq) (concat result))
+            ((vectorp seq) (vconcat result))
+            (t (error "Unsupported sequence: %s" seq))))))
+
+(defun seq-contains-p (seq elt &optional testfn)
+  "Return the first element in SEQ that equals to ELT.
+Equality is defined by TESTFN if non-nil or by `equal' if nil."
+  (seq-some-p (lambda (e)
+                (funcall (or testfn #'equal) elt e))
+              seq))
+
+(defun seq-uniq (seq &optional testfn)
+  "Return a list of the elements of SEQ with duplicates removed.
+Use TESTFN to compare elements, or `equal' if TESTFN is nil."
+  (let ((result '()))
+    (seq-doseq (elt seq)
+      (unless (seq-contains-p result elt testfn)
+        (setq result (cons elt result))))
+    (nreverse result)))
+
+(defun seq-subseq (seq start &optional end)
+  "Return the subsequence of SEQ from START to END.
+If END is omitted, it defaults to the length of the sequence.
+If START or END is negative, it counts from the end."
+  (cond ((or (stringp seq) (vectorp seq)) (substring seq start end))
+        ((listp seq)
+         (let (len)
+           (and end (< end 0) (setq end (+ end (setq len (seq-length seq)))))
+           (if (< start 0) (setq start (+ start (or len (setq len (seq-length seq))))))
+           (if (> start 0) (setq seq (nthcdr start seq)))
+           (if end
+               (let ((res nil))
+                 (while (>= (setq end (1- end)) start)
+                   (push (pop seq) res))
+                 (nreverse res))
+             (seq-copy seq))))
+        (t (error "Unsupported sequence: %s" seq))))
+
+(defun seq-concatenate (type &rest seqs)
+  "Concatenate, into a sequence of type TYPE, the sequences SEQS.
+TYPE must be one of following symbols: vector, string or list.
+
+\n(fn TYPE SEQUENCE...)"
+  (pcase type
+    (`vector (apply #'vconcat seqs))
+    (`string (apply #'concat seqs))
+    (`list (apply #'append (append seqs '(nil))))
+    (t (error "Not a sequence type name: %s" type))))
+
+(defalias 'seq-copy #'copy-sequence)
+(defalias 'seq-elt #'elt)
+(defalias 'seq-reverse #'reverse)
+(defalias 'seq-length #'length)
+(defalias 'seq-do #'mapc)
+(defalias 'seq-each #'seq-do)
+(defalias 'seq-map #'mapcar)
+
+(provide 'seq)
+;;; seq.el ends here
diff --git a/test/ChangeLog b/test/ChangeLog
index d0988e4..776963a 100644
--- a/test/ChangeLog
+++ b/test/ChangeLog
@@ -1,3 +1,7 @@
+2014-11-24  Nicolas Petton <petton.nicolas@gmail.com>
+
+	* automated/seq-tests.el: New file.
+
 2014-11-21  Ulf Jasper  <ulf.jasper@web.de>
 
 	* automated/libxml-tests.el
diff --git a/test/automated/seq-tests.el b/test/automated/seq-tests.el
new file mode 100644
index 0000000..31a05ac
--- /dev/null
+++ b/test/automated/seq-tests.el
@@ -0,0 +1,177 @@
+;;; seq-tests.el --- Tests for sequences.el
+
+;; Copyright (C) 2014 Free Software Foundation, Inc.
+
+;; Author: Nicolas Petton <petton.nicolas@gmail.com>
+;; Maintainer: emacs-devel@gnu.org
+
+;; This file is part of GNU Emacs.
+
+;; GNU Emacs is free software: you can redistribute it and/or modify
+;; it under the terms of the GNU General Public License as published by
+;; the Free Software Foundation, either version 3 of the License, or
+;; (at your option) any later version.
+
+;; GNU Emacs is distributed in the hope that it will be useful,
+;; but WITHOUT ANY WARRANTY; without even the implied warranty of
+;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+;; GNU General Public License for more details.
+
+;; You should have received a copy of the GNU General Public License
+;; along with GNU Emacs.  If not, see <http://www.gnu.org/licenses/>.
+
+;;; Commentary:
+
+;; Tests for sequences.el
+
+;;; Code:
+
+(require 'ert)
+(require 'seq)
+
+(defmacro with-test-sequences (spec &rest body)
+  "Successively bind VAR to a list, vector, and string built from SEQ.
+Evaluate BODY for each created sequence.
+
+\(fn (var seq) body)"
+  (declare (indent 1) (debug ((symbolp form) body)))
+  (let ((initial-seq (make-symbol "initial-seq")))
+    `(let ((,initial-seq ,(cadr spec)))
+       ,@(mapcar (lambda (s)
+                   `(let ((,(car spec) (apply (function ,s) ,initial-seq)))
+                      ,@body))
+                 '(list vector string)))))
+
+(defun same-contents-p (seq1 seq2)
+  "Return t if SEQ1 and SEQ2 have the same contents, nil otherwise."
+  (equal (append seq1 '()) (append seq2 '())))
+
+(defun test-sequences-evenp (integer)
+  "Return t if INTEGER is even."
+  (eq (logand integer 1) 0))
+
+(defun test-sequences-oddp (integer)
+  "Return t if INTEGER is odd."
+  (not (test-sequences-evenp integer)))
+
+(ert-deftest test-seq-drop ()
+  (with-test-sequences (seq '(1 2 3 4))
+    (should (equal (seq-drop seq 0) seq))
+    (should (equal (seq-drop seq 1) (seq-subseq seq 1)))
+    (should (equal (seq-drop seq 2) (seq-subseq seq 2)))
+    (should (seq-empty-p (seq-drop seq 4)))
+    (should (seq-empty-p (seq-drop seq 10))))
+  (with-test-sequences (seq '())
+    (should (seq-empty-p (seq-drop seq 0)))
+    (should (seq-empty-p (seq-drop seq 1)))))
+
+(ert-deftest test-seq-take ()
+  (with-test-sequences (seq '(2 3 4 5))
+    (should (seq-empty-p (seq-take seq 0)))
+    (should (= (seq-length (seq-take seq 1)) 1))
+    (should (= (seq-elt (seq-take seq 1) 0) 2))
+    (should (same-contents-p (seq-take seq 3) '(2 3 4)))
+    (should (equal (seq-take seq 10) seq))))
+
+(ert-deftest test-seq-filter ()
+  (with-test-sequences (seq '(6 7 8 9 10))
+    (should (equal (seq-filter #'test-sequences-evenp seq) '(6 8 10)))
+    (should (equal (seq-filter #'test-sequences-oddp seq) '(7 9)))
+    (should (equal (seq-filter (lambda (elt) nil) seq) '())))
+  (with-test-sequences (seq '())
+    (should (equal (seq-filter #'test-sequences-evenp seq) '()))))
+
+(ert-deftest test-seq-remove ()
+  (with-test-sequences (seq '(6 7 8 9 10))
+    (should (equal (seq-remove #'test-sequences-evenp seq) '(7 9)))
+    (should (equal (seq-remove #'test-sequences-oddp seq) '(6 8 10)))
+    (should (same-contents-p (seq-remove (lambda (elt) nil) seq) seq)))
+  (with-test-sequences (seq '())
+    (should (equal (seq-remove #'test-sequences-evenp seq) '()))))
+
+(ert-deftest test-seq-count ()
+  (with-test-sequences (seq '(6 7 8 9 10))
+    (should (equal (seq-count #'test-sequences-evenp seq) 3))
+    (should (equal (seq-count #'test-sequences-oddp seq) 2))
+    (should (equal (seq-count (lambda (elt) nil) seq) 0)))
+  (with-test-sequences (seq '())
+    (should (equal (seq-count #'test-sequences-evenp seq) 0))))
+
+(ert-deftest test-seq-reduce ()
+  (with-test-sequences (seq '(1 2 3 4))
+    (should (= (seq-reduce #'+ seq 0) 10))
+    (should (= (seq-reduce #'+ seq 5) 15)))
+  (with-test-sequences (seq '())
+    (should (eq (seq-reduce #'+ seq 0) 0))
+    (should (eq (seq-reduce #'+ seq 7) 7))))
+
+(ert-deftest test-seq-some-p ()
+  (with-test-sequences (seq '(4 3 2 1))
+    (should (= (seq-some-p #'test-sequences-evenp seq) 4))
+    (should (= (seq-some-p #'test-sequences-oddp seq) 3))
+    (should-not (seq-some-p (lambda (elt) (> elt 10)) seq)))
+  (with-test-sequences (seq '())
+    (should-not (seq-some-p #'test-sequences-oddp seq))))
+
+(ert-deftest test-seq-contains-p ()
+  (with-test-sequences (seq '(3 4 5 6))
+    (should (seq-contains-p seq 3))
+    (should-not (seq-contains-p seq 7)))
+  (with-test-sequences (seq '())
+    (should-not (seq-contains-p seq 3))
+    (should-not (seq-contains-p seq nil))))
+
+(ert-deftest test-seq-every-p ()
+  (with-test-sequences (seq '(43 54 22 1))
+    (should (seq-every-p (lambda (elt) t) seq))
+    (should-not (seq-every-p #'test-sequences-oddp seq))
+    (should-not (seq-every-p #'test-sequences-evenp seq)))
+  (with-test-sequences (seq '(42 54 22 2))
+    (should (seq-every-p #'test-sequences-evenp seq))
+    (should-not (seq-every-p #'test-sequences-oddp seq)))
+  (with-test-sequences (seq '())
+    (should (seq-every-p #'identity seq))
+    (should (seq-every-p #'test-sequences-evenp seq))))
+
+(ert-deftest test-seq-empty-p ()
+  (with-test-sequences (seq '(0))
+    (should-not (seq-empty-p seq)))
+  (with-test-sequences (seq '(0 1 2))
+    (should-not (seq-empty-p seq)))
+  (with-test-sequences (seq '())
+    (should (seq-empty-p seq))))
+
+(ert-deftest test-seq-sort ()
+  (should (equal (seq-sort #'< "cbaf") "abcf"))
+  (should (equal (seq-sort #'< '(2 1 9 4)) '(1 2 4 9)))
+  (should (equal (seq-sort #'< [2 1 9 4]) [1 2 4 9]))
+  (should (equal (seq-sort #'< "") "")))
+
+(ert-deftest test-seq-uniq ()
+  (with-test-sequences (seq '(2 4 6 8 6 4 3))
+    (should (equal (seq-uniq seq) '(2 4 6 8 3))))
+  (with-test-sequences (seq '(3 3 3 3 3))
+    (should (equal (seq-uniq seq) '(3))))
+  (with-test-sequences (seq '())
+    (should (equal (seq-uniq seq) '()))))
+
+(ert-deftest test-seq-subseq ()
+  (with-test-sequences (seq '(2 3 4 5))
+    (should (equal (seq-subseq seq 0 4) seq))
+    (should (same-contents-p (seq-subseq seq 2 4) '(4 5)))
+    (should (same-contents-p (seq-subseq seq 1 3) '(3 4)))
+    (should (same-contents-p (seq-subseq seq 1 -1) '(3 4))))
+  (should (vectorp (seq-subseq [2 3 4 5] 2)))
+  (should (stringp (seq-subseq "foo" 2 3)))
+  (should (listp (seq-subseq '(2 3 4 4) 2 3))))
+
+(ert-deftest test-seq-concatenate ()
+  (with-test-sequences (seq '(2 4 6))
+    (should (equal (seq-concatenate 'string seq [8]) (string 2 4 6 8)))
+    (should (equal (seq-concatenate 'list seq '(8 10)) '(2 4 6 8 10)))
+    (should (equal (seq-concatenate 'vector seq '(8 10)) [2 4 6 8 10]))
+    (should (equal (seq-concatenate 'vector nil '(8 10)) [8 10]))
+    (should (equal (seq-concatenate 'vector seq nil) [2 4 6]))))
+
+(provide 'seq-tests)
+;;; seq-tests.el ends here

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Nico


Nicolas Petton <petton.nicolas@gmail.com> writes:

> Hi,
>
> Here's a new version of the patch.
>
>
> I fixed all the byte-compile warnings, added an alias for `reverse', and
> improved `seq-doseq'.
>
> Stefan, can you have another look at seq-doseq?
>
> Cheers,
> Nico
>
> Stefan Monnier <monnier@IRO.UMontreal.CA> writes:
>
>>>>> The macro could use to "dolist" if the sequence is a list.
>>>> But you'd then duplicate the code of the body, which could be
>>>> problematic, especially with nested seq-doseq loops.
>>> Oh, right! Another way would be to use a function, but I tried to avoid
>>> that. Do you have a better idea in mind?
>>
>> You can change your `i' to be either an integer (for arrays) or a cons
>> cell (for lists).  That requires an extra "is it a list?" test at each
>> iteration of the loop (to know how to extract the element and to
>> "increment" i), but I think it's the best we can do.
>>
>>
>>         Stefan

-- 
Nicolas Petton
http://nicolas-petton.fr