From mboxrd@z Thu Jan 1 00:00:00 1970 Path: news.gmane.org!not-for-mail From: Mark H Weaver Newsgroups: gmane.lisp.guile.devel Subject: [PATCH] psyntax: custom ellipses using 'with-ellipsis' or R7RS syntax-rules Date: Wed, 18 Dec 2013 19:33:06 -0500 Message-ID: <87bo0del31.fsf@netris.org> NNTP-Posting-Host: plane.gmane.org Mime-Version: 1.0 Content-Type: multipart/mixed; boundary="=-=-=" X-Trace: ger.gmane.org 1387413337 22902 80.91.229.3 (19 Dec 2013 00:35:37 GMT) X-Complaints-To: usenet@ger.gmane.org NNTP-Posting-Date: Thu, 19 Dec 2013 00:35:37 +0000 (UTC) To: guile-devel@gnu.org Original-X-From: guile-devel-bounces+guile-devel=m.gmane.org@gnu.org Thu Dec 19 01:35:40 2013 Return-path: Envelope-to: guile-devel@m.gmane.org Original-Received: from lists.gnu.org ([208.118.235.17]) by plane.gmane.org with esmtp (Exim 4.69) (envelope-from ) id 1VtRaU-0003CK-Ah for guile-devel@m.gmane.org; Thu, 19 Dec 2013 01:35:38 +0100 Original-Received: from localhost ([::1]:41435 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1VtRaT-0003AA-RN for guile-devel@m.gmane.org; Wed, 18 Dec 2013 19:35:37 -0500 Original-Received: from eggs.gnu.org ([2001:4830:134:3::10]:39258) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1VtRaC-000390-Rd for guile-devel@gnu.org; Wed, 18 Dec 2013 19:35:25 -0500 Original-Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1VtRa3-00016w-TW for guile-devel@gnu.org; Wed, 18 Dec 2013 19:35:20 -0500 Original-Received: from world.peace.net ([96.39.62.75]:51822) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1VtRa3-0000ob-FA for guile-devel@gnu.org; Wed, 18 Dec 2013 19:35:11 -0500 Original-Received: from 209-6-91-212.c3-0.smr-ubr1.sbo-smr.ma.cable.rcn.com ([209.6.91.212] helo=yeeloong) by world.peace.net with esmtpsa (TLS1.0:DHE_RSA_AES_128_CBC_SHA1:16) (Exim 4.72) (envelope-from ) id 1VtRZW-00061V-Dk; Wed, 18 Dec 2013 19:34:39 -0500 X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.6.x X-Received-From: 96.39.62.75 X-BeenThere: guile-devel@gnu.org X-Mailman-Version: 2.1.14 Precedence: list List-Id: "Developers list for Guile, the GNU extensibility library" List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: guile-devel-bounces+guile-devel=m.gmane.org@gnu.org Original-Sender: guile-devel-bounces+guile-devel=m.gmane.org@gnu.org Xref: news.gmane.org gmane.lisp.guile.devel:16780 Archived-At: --=-=-= Content-Type: text/plain Hello all, This patch implements a new primitive syntax form 'with-ellipsis' that changes the ellipsis identifier within a lexical scope, and uses this to implement the R7RS extension to 'syntax-rules'. I'd like to apply this to the stable-2.0 branch. It took me quite a while to figure out the right way to generalize this R7RS feature for the syntax-case system. My first idea was to make 'syntax' a syntax parameter, but further thought made it clear that this would be inadequate. Consider all of the other macros based on 'syntax' and 'syntax-case': things such as 'with-syntax', 'quasisyntax', etc. It was obvious that 'with-ellipsis' should modify the lexical environment somehow, but how? First of all, consider that a single 'syntax' or 'syntax-case' form might, in general, be composed of identifiers from many different lexical environments. The lexical environment of the 'syntax' keyword is not the right environment to look at for the entire template, because in a 'quasisyntax' or 'syntax-rules' form, that's the lexical environment of the 'quasisyntax' or 'syntax-rules' macro. It soon became clear that I must search the lexical environment of each identifier within a pattern or template to determine if that identifier is an ellipsis. But what identifier should it look up in that lexical environment? Again, my first thought was to look up the identifier itself, but that's not right either. A 'with-ellipsis' form must not only add a new ellipsis identifier; it must also disable the special meaning of the previous ellipsis identifier. In the end, here's how this works: 'with-ellipsis' binds a special identifier named #{ $sc-ellipsis }# using a new 'ellipsis' binding type. The new ellipsis identifier is stored within the binding. In order to determine whether an identifier X is an ellipsis, the binding for #{ $sc-ellipsis }# is looked up in the lexical environment of X. If the binding is found and has binding-type 'ellipsis', then X is compared to the identifier stored in the binding using 'bound-id=?'. Otherwise, X is compared to '...' using 'free-id=?' as was done before. After much thought, I'm fairly confident that this is the only good approach. I'd like to push this to stable-2.0. Comments and suggestions welcome. --=-=-= Content-Type: text/x-patch; charset=utf-8 Content-Disposition: inline; filename=0001-psyntax-custom-ellipses-using-with-ellipsis-or-R7RS-.patch Content-Transfer-Encoding: quoted-printable Content-Description: [PATCH] psyntax: custom ellipses using 'with-ellipsis' or R7RS syntax-rules >From 619bb46010696f232f09f124049739becfe94611 Mon Sep 17 00:00:00 2001 From: Mark H Weaver Date: Wed, 18 Dec 2013 18:49:37 -0500 Subject: [PATCH] psyntax: custom ellipses using 'with-ellipsis' or R7RS syntax-rules. * module/ice-9/psyntax.scm (binding-type): Update the header comment to mention the new 'ellipsis' binding type. (ellipsis?): Add 'r' and 'mod' as arguments. Search the lexical environment for an ellipsis binding, and use it. (gen-syntax): Adapt to the additional arguments of 'ellipsis?'. (with-ellipsis): New core syntax. (convert-pattern): Add unary 'ellipsis?' procedure as an argument. (gen-clause): Adapt to the additional arguments of 'ellipsis?'. Pass unary 'ellipsis?' procedure to 'convert-pattern'. (syntax-case): Adapt to the additional arguments of 'ellipsis?'. (syntax-local-binding): Support new 'ellipsis' binding type. (syntax-rules): Add support for a custom ellipsis identifier as the first operand, as per R7RS. Collect common code within new local procedure 'expand-syntax-rules'. * module/ice-9/psyntax-pp.scm: Regenerate. * module/ice-9/local-eval.scm (analyze-identifiers): Add support for 'ellipsis' binding type. * doc/ref/api-macros.texi (Syntax Rules): Add docs for R7RS custom ellipsis syntax. Use @dots{}. (Syntax Case): Add docs for 'with-ellipsis'. Use @dots{}. (Syntax Transformer Helpers): Update to include new 'ellipsis' binding type. * test-suite/tests/syntax.test: Add tests. --- doc/ref/api-macros.texi | 73 +++++++++++++- module/ice-9/local-eval.scm | 8 ++- module/ice-9/psyntax-pp.scm | 225 ++++++++++++++++++++++++++++++--------= ---- module/ice-9/psyntax.scm | 108 +++++++++++++++----- test-suite/tests/syntax.test | 106 ++++++++++++++++++++- 5 files changed, 423 insertions(+), 97 deletions(-) diff --git a/doc/ref/api-macros.texi b/doc/ref/api-macros.texi index a3fa83f..61137f0 100644 --- a/doc/ref/api-macros.texi +++ b/doc/ref/api-macros.texi @@ -136,7 +136,7 @@ same @var{letrec-syntax}. @code{syntax-rules} macros are simple, pattern-driven syntax transformers,= with a beauty worthy of Scheme. =20 -@deffn {Syntax} syntax-rules literals (pattern template)... +@deffn {Syntax} syntax-rules literals (pattern template) @dots{} Create a syntax transformer that will rewrite an expression using the rules embodied in the @var{pattern} and @var{template} clauses. @end deffn @@ -363,6 +363,26 @@ Cast into this form, our @code{when} example is signif= icantly shorter: (if c (begin e ...))) @end example =20 +@subsubsection Specifying a custom ellipsis identifier + +When writing macros that generate macro definitions, it is convenient to +use a different ellipsis identifier at each level. Guile allows the +desired ellipsis identifier to be specified as the first operand to +@code{syntax-rules}, as per R7RS. For example: + +@example +(define-syntax define-quotation-macros + (syntax-rules () + ((_ (macro-name head-symbol) ...) + (begin (define-syntax macro-name + (syntax-rules ::: () + ((_ x :::) + (quote (head-symbol x :::))))) + ...)))) +(define-quotation-macros (quote-a a) (quote-b b) (quote-c c)) +(quote-a 1 2 3) @result{} (a 1 2 3) +@end example + @subsubsection Further Information =20 For a formal definition of @code{syntax-rules} and its pattern language, s= ee @@ -389,7 +409,7 @@ Primer for the Merely Eccentric}. @code{syntax-case} macros are procedural syntax transformers, with a power worthy of Scheme. =20 -@deffn {Syntax} syntax-case syntax literals (pattern [guard] exp)... +@deffn {Syntax} syntax-case syntax literals (pattern [guard] exp) @dots{} Match the syntax object @var{syntax} against the given patterns, in order.= If a @var{pattern} matches, return the result of evaluating the associated @var= {exp}. @end deffn @@ -631,9 +651,9 @@ variable environment, and we can do so using @code{synt= ax-case} itself: However there are easier ways to write this. @code{with-syntax} is often convenient: =20 -@deffn {Syntax} with-syntax ((pat val)...) exp... +@deffn {Syntax} with-syntax ((pat val) @dots{}) exp @dots{} Bind patterns @var{pat} from their corresponding values @var{val}, within = the -lexical context of @var{exp...}. +lexical context of @var{exp} @enddots{}. =20 @example ;; better @@ -681,6 +701,44 @@ edition 3 or 4, in the chapter on syntax. Dybvig was t= he primary author of the @code{syntax-case} system. The book itself is available online at @uref{http://scheme.com/tspl4/}. =20 +@subsubsection Custom ellipsis identifiers for syntax-case macros + +When writing procedural macros that generate macro definitions, it is +convenient to use a different ellipsis identifier at each level. Guile +supports this for procedural macros using the @code{with-ellipsis} +special form: + +@deffn {Syntax} with-ellipsis ellipsis body @dots{} +@var{ellipsis} must be an identifier. Evaluate @var{body} in a special +lexical environment such that all macro patterns and templates within +@var{body} will use @var{ellipsis} as the ellipsis identifier instead of +the usual three dots (@code{...}). +@end deffn + +For example: + +@example +(define-syntax define-quotation-macros + (lambda (x) + (syntax-case x () + ((_ (macro-name head-symbol) ...) + #'(begin (define-syntax macro-name + (lambda (x) + (with-ellipsis ::: + (syntax-case x () + ((_ x :::) + #'(quote (head-symbol x :::))))))) + ...))))) +(define-quotation-macros (quote-a a) (quote-b b) (quote-c c)) +(quote-a 1 2 3) @result{} (a 1 2 3) +@end example + +Note that the effect of @code{with-ellipsis} does not propagate within +nested syntax binding forms such as @code{define-syntax}, +@code{let-syntax}, or @code{letrec-syntax}. It also does not affect the +ellipsis identifier of the generated code, unless @code{with-ellipsis} +is included around the generated code. + @node Syntax Transformer Helpers @subsection Syntax Transformer Helpers =20 @@ -740,8 +798,11 @@ of @code{eq?}) identifying this binding. A syntax transformer, either local or global. The value is the transformer procedure. @item pattern-variable -A pattern variable, bound via syntax-case. The value is an opaque -object, internal to the expander. +A pattern variable, bound via @code{syntax-case}. The value is an +opaque object, internal to the expander. +@item ellipsis +An internal binding, bound via @code{with-ellipsis}. The value is the +(anti-marked) local ellipsis identifier. @item displaced-lexical A lexical variable that has gone out of scope. This can happen if a badly-written procedural macro saves a syntax object, then attempts to diff --git a/module/ice-9/local-eval.scm b/module/ice-9/local-eval.scm index 28f30b9..bd3588b 100644 --- a/module/ice-9/local-eval.scm +++ b/module/ice-9/local-eval.scm @@ -1,6 +1,6 @@ ;;; -*- mode: scheme; coding: utf-8; -*- ;;; -;;; Copyright (C) 2012 Free Software Foundation, Inc. +;;; Copyright (C) 2012, 2013 Free Software Foundation, Inc. ;;; ;;; This library is free software; you can redistribute it and/or ;;; modify it under the terms of the GNU Lesser General Public @@ -179,6 +179,12 @@ (cdr val) t) patterns)))) + ((ellipsis) + (lp ids capture formals + (cons (lambda (x) + #`(with-ellipsis #,val #,x)) + wrappers) + patterns)) (else (error "what" type val)))))))))) =20 diff --git a/module/ice-9/psyntax-pp.scm b/module/ice-9/psyntax-pp.scm index f5f764b..a9015b2 100644 --- a/module/ice-9/psyntax-pp.scm +++ b/module/ice-9/psyntax-pp.scm @@ -1096,9 +1096,17 @@ (syntax-violation #f "nonprocedure transformer" p))))) (expand-void (lambda () (build-void #f))) (ellipsis? - (lambda (x) - (and (nonsymbol-id? x) - (free-id=3D? x '#(syntax-object ... ((top)) (hygiene guile))))= )) + (lambda (e r mod) + (and (nonsymbol-id? e) + (let* ((id (make-syntax-object + '#{ $sc-ellipsis }# + (syntax-object-wrap e) + (syntax-object-module e))) + (n (id-var-name id '(()))) + (b (lookup n r mod))) + (if (eq? (car b) 'ellipsis) + (bound-id=3D? e (cdr b)) + (free-id=3D? e '#(syntax-object ... ((top)) (hygiene guile= )))))))) (lambda-formals (lambda (orig-args) (letrec* @@ -1567,14 +1575,15 @@ (let ((var.lev (cdr b))) (gen-ref src (car var.lev) (cdr var.lev) maps)= )) (lambda (var maps) (values (list 'ref var) maps)))) - ((ellipsis? e) (syntax-violation 'syntax "misplaced e= llipsis" src)) + ((ellipsis? e r mod) + (syntax-violation 'syntax "misplaced ellipsis" src)) (else (values (list 'quote e) maps)))) (let* ((tmp e) (tmp-1 ($sc-dispatch tmp '(any any)))) - (if (and tmp-1 (apply (lambda (dots e) (ellipsis? dots)) tm= p-1)) - (apply (lambda (dots e) (gen-syntax src e r maps (lambda = (x) #f) mod)) + (if (and tmp-1 (apply (lambda (dots e) (ellipsis? dots r mo= d)) tmp-1)) + (apply (lambda (dots e) (gen-syntax src e r maps (lambda = (e r mod) #f) mod)) tmp-1) (let ((tmp-1 ($sc-dispatch tmp '(any any . any)))) - (if (and tmp-1 (apply (lambda (x dots y) (ellipsis? dot= s)) tmp-1)) + (if (and tmp-1 (apply (lambda (x dots y) (ellipsis? dot= s r mod)) tmp-1)) (apply (lambda (x dots y) (let f ((y y) (k (lambda (maps) @@ -1585,7 +1594,7 @@ (syntax-violation 'syntax= "extra ellipsis" src) (values (gen-map x (car m= aps)) (cdr maps)))))))) (let* ((tmp y) (tmp ($sc-dispatch tmp '(an= y . any)))) - (if (and tmp (apply (lambda (dots y) (el= lipsis? dots)) tmp)) + (if (and tmp (apply (lambda (dots y) (el= lipsis? dots r mod)) tmp)) (apply (lambda (dots y) (f y (lambda (maps) @@ -1810,6 +1819,30 @@ (syntax-violation 'case-lambda "bad case-lambda*" e)))))))) (global-extend 'core + 'with-ellipsis + (lambda (e r w s mod) + (let* ((tmp e) (tmp ($sc-dispatch tmp '(_ any any . each-any)))) + (if (and tmp (apply (lambda (dots e1 e2) (id? dots)) tmp)) + (apply (lambda (dots e1 e2) + (let ((id (if (symbol? dots) + '#{ $sc-ellipsis }# + (make-syntax-object + '#{ $sc-ellipsis }# + (syntax-object-wrap dots) + (syntax-object-module dots))))) + (let ((ids (list id)) + (labels (list (gen-label))) + (bindings (list (cons 'ellipsis (source-wrap do= ts w s mod))))) + (let ((nw (make-binding-wrap ids labels w)) + (nr (extend-env labels bindings r))) + (expand-body (cons e1 e2) (source-wrap e nw s mod= ) nr nw mod))))) + tmp) + (syntax-violation + 'with-ellipsis + "bad syntax" + (source-wrap e w s mod)))))) + (global-extend + 'core 'let (letrec* ((expand-let @@ -2069,7 +2102,7 @@ 'syntax-case (letrec* ((convert-pattern - (lambda (pattern keys) + (lambda (pattern keys ellipsis?) (letrec* ((cvt* (lambda (p* n ids) (let* ((tmp p*) (tmp ($sc-dispatch tmp '(any . any))= )) @@ -2163,9 +2196,10 @@ (gen-clause (lambda (x keys clauses r pat fender exp mod) (call-with-values - (lambda () (convert-pattern pat keys)) + (lambda () + (convert-pattern pat keys (lambda (e) (ellipsis? e r mod)))) (lambda (p pvars) - (cond ((not (and-map (lambda (x) (not (ellipsis? (car x))))= pvars)) + (cond ((not (and-map (lambda (x) (not (ellipsis? (car x) r = mod))) pvars)) (syntax-violation 'syntax-case "misplaced ellipsis" = pat)) ((not (distinct-bound-ids? (map car pvars))) (syntax-violation 'syntax-case "duplicate pattern va= riable" pat)) @@ -2245,7 +2279,7 @@ (tmp ($sc-dispatch tmp-1 '(_ any each-any . each-any)))) (if tmp (apply (lambda (val key m) - (if (and-map (lambda (x) (and (id? x) (not (ellipsis?= x)))) key) + (if (and-map (lambda (x) (and (id? x) (not (ellipsis?= x r mod)))) key) (let ((x (gen-var 'tmp))) (build-application s @@ -2361,6 +2395,13 @@ ((memv key '(syntax)) (values 'pattern-variable= value)) ((memv key '(displaced-lexical)) (values 'displ= aced-lexical #f)) ((memv key '(global)) (values 'global (cons val= ue (cdr mod)))) + ((memv key '(ellipsis)) + (values + 'ellipsis + (make-syntax-object + (syntax-object-expression value) + (anti-mark (syntax-object-wrap value)) + (syntax-object-module value)))) (else (values 'other #f))))))))))) (syntax-locally-bound-identifiers (lambda (id) @@ -2547,56 +2588,116 @@ 'syntax-rules 'macro (lambda (xx) - (let ((tmp-1 xx)) - (let ((tmp ($sc-dispatch tmp-1 '(_ each-any . #(each ((any . any) = any)))))) - (if tmp - (apply (lambda (k keyword pattern template) - (list '#(syntax-object lambda ((top)) (hygiene guile)) - '(#(syntax-object x ((top)) (hygiene guile))) - (vector - '(#(syntax-object macro-type ((top)) (hygiene= guile)) - . - #(syntax-object syntax-rules ((top)) (hygie= ne guile))) - (cons '#(syntax-object patterns ((top)) (hygi= ene guile)) pattern)) - (cons '#(syntax-object syntax-case ((top)) (hyg= iene guile)) - (cons '#(syntax-object x ((top)) (hygiene= guile)) - (cons k - (map (lambda (tmp-1 tmp) - (list (cons '#(syntax-= object dummy ((top)) (hygiene guile)) tmp) - (list '#(syntax-= object syntax ((top)) (hygiene guile)) - tmp-1))) - template - pattern)))))) - tmp) - (let ((tmp ($sc-dispatch tmp-1 '(_ each-any any . #(each ((any= . any) any)))))) - (if (if tmp - (apply (lambda (k docstring keyword pattern template) - (string? (syntax->datum docstring))) - tmp) - #f) - (apply (lambda (k docstring keyword pattern template) - (list '#(syntax-object lambda ((top)) (hygiene gu= ile)) - '(#(syntax-object x ((top)) (hygiene guile)= )) - docstring - (vector - '(#(syntax-object macro-type ((top)) (hyg= iene guile)) - . - #(syntax-object syntax-rules ((top)) (h= ygiene guile))) - (cons '#(syntax-object patterns ((top)) (= hygiene guile)) pattern)) - (cons '#(syntax-object syntax-case ((top)) = (hygiene guile)) - (cons '#(syntax-object x ((top)) (hyg= iene guile)) - (cons k - (map (lambda (tmp-1 tmp) - (list (cons '#(syn= tax-object dummy ((top)) (hygiene guile)) tmp) - (list '#(syn= tax-object syntax ((top)) (hygiene guile)) - tmp-1)= )) - template - pattern)))))) - tmp) - (syntax-violation - #f - "source expression failed to match any pattern" - tmp-1))))))))) + (letrec* + ((expand-syntax-rules + (lambda (dots keys docstrings clauses) + (let ((tmp-1 (list keys docstrings clauses))) + (let ((tmp ($sc-dispatch tmp-1 '(each-any each-any #(each (= (any . any) any)))))) + (if tmp + (apply (lambda (k docstring keyword pattern template) + (let ((tmp (cons '#(syntax-object lambda ((top= )) (hygiene guile)) + (cons '(#(syntax-object x ((t= op)) (hygiene guile))) + (append + docstring + (list (vector + '(#(syntax-ob= ject macro-type ((top)) (hygiene guile)) + . + #(syntax-ob= ject syntax-rules ((top)) (hygiene guile))) + (cons '#(synt= ax-object patterns ((top)) (hygiene guile)) + pattern= )) + (cons '#(syntax= -object syntax-case ((top)) (hygiene guile)) + (cons '#(= syntax-object x ((top)) (hygiene guile)) + (co= ns k + = (map (lambda (tmp-1 tmp) + = (list (cons '#(syntax-object + = dummy + = ((top)) + = (hygiene guile)) + = tmp) + = (list '#(syntax-object + = syntax + = ((top)) + = (hygiene guile)) + = tmp-1))) + = template + = pattern)))))))))) + (let ((form tmp)) + (if dots + (let ((tmp dots)) + (let ((dots tmp)) + (list '#(syntax-object with-ellipsis= ((top)) (hygiene guile)) + dots + form))) + form)))) + tmp) + (syntax-violation + #f + "source expression failed to match any pattern" + tmp-1))))))) + (let ((tmp xx)) + (let ((tmp-1 ($sc-dispatch tmp '(_ each-any . #(each ((any . any= ) any)))))) + (if tmp-1 + (apply (lambda (k keyword pattern template) + (expand-syntax-rules + #f + k + '() + (map (lambda (tmp-2 tmp-1 tmp) (list (cons tmp tm= p-1) tmp-2)) + template + pattern + keyword))) + tmp-1) + (let ((tmp-1 ($sc-dispatch tmp '(_ each-any any . #(each ((a= ny . any) any)))))) + (if (if tmp-1 + (apply (lambda (k docstring keyword pattern template) + (string? (syntax->datum docstring))) + tmp-1) + #f) + (apply (lambda (k docstring keyword pattern template) + (expand-syntax-rules + #f + k + (list docstring) + (map (lambda (tmp-2 tmp-1 tmp) (list (cons tm= p tmp-1) tmp-2)) + template + pattern + keyword))) + tmp-1) + (let ((tmp-1 ($sc-dispatch tmp '(_ any each-any . #(each= ((any . any) any)))))) + (if (if tmp-1 + (apply (lambda (dots k keyword pattern template)= (identifier? dots)) + tmp-1) + #f) + (apply (lambda (dots k keyword pattern template) + (expand-syntax-rules + dots + k + '() + (map (lambda (tmp-2 tmp-1 tmp) (list (con= s tmp tmp-1) tmp-2)) + template + pattern + keyword))) + tmp-1) + (let ((tmp-1 ($sc-dispatch tmp '(_ any each-any any = . #(each ((any . any) any)))))) + (if (if tmp-1 + (apply (lambda (dots k docstring keyword pat= tern template) + (if (identifier? dots) (string? (sy= ntax->datum docstring)) #f)) + tmp-1) + #f) + (apply (lambda (dots k docstring keyword pattern= template) + (expand-syntax-rules + dots + k + (list docstring) + (map (lambda (tmp-2 tmp-1 tmp) (list = (cons tmp tmp-1) tmp-2)) + template + pattern + keyword))) + tmp-1) + (syntax-violation + #f + "source expression failed to match any pattern" + tmp)))))))))))))) =20 (define define-syntax-rule (make-syntax-transformer diff --git a/module/ice-9/psyntax.scm b/module/ice-9/psyntax.scm index fa009d2..143d4c7 100644 --- a/module/ice-9/psyntax.scm +++ b/module/ice-9/psyntax.scm @@ -42,6 +42,9 @@ ;;; Modified by Andy Wingo according to the Git ;;; revision control logs corresponding to this file: 2009, 2010. =20 +;;; Modified by Mark H Weaver according to the Git +;;; revision control logs corresponding to this file: 2012, 2013. + =20 ;;; This code is based on "Syntax Abstraction in Scheme" ;;; by R. Kent Dybvig, Robert Hieb, and Carl Bruggeman. @@ -509,6 +512,7 @@ ;; (syntax . ( . )) pattern variables ;; (global) assumed global variab= le ;; (lexical . ) lexical variables + ;; (ellipsis . ) custom ellipsis ;; (displaced-lexical) displaced lexicals ;; ::=3D ;; ::=3D variable returned by build-lexical-var @@ -528,6 +532,9 @@ =20 ;; a lexical variable is a lambda- or letrec-bound variable. =20 + ;; an ellipsis binding is introduced by the 'with-ellipsis' special + ;; form. + ;; a displaced-lexical identifier is a lexical identifier removed from ;; it's scope by the return of a syntax object containing the identifi= er. ;; a displaced lexical can also appear when a letrec-syntax-bound @@ -1574,9 +1581,22 @@ (build-void no-source))) =20 (define ellipsis? - (lambda (x) - (and (nonsymbol-id? x) - (free-id=3D? x #'(... ...))))) + (lambda (e r mod) + (and (nonsymbol-id? e) + ;; If there is a binding for the special identifier + ;; #{ $sc-ellipsis }# in the lexical environment of E, + ;; and if the associated binding type is 'ellipsis', + ;; then the binding's value specifies the custom ellipsis + ;; identifier within that lexical environment, and the + ;; comparison is done using 'bound-id=3D?'. + (let* ((id (make-syntax-object '#{ $sc-ellipsis }# + (syntax-object-wrap e) + (syntax-object-module e))) + (n (id-var-name id empty-wrap)) + (b (lookup n r mod))) + (if (eq? (binding-type b) 'ellipsis) + (bound-id=3D? e (binding-value b)) + (free-id=3D? e #'(... ...))))))) =20 (define lambda-formals (lambda (orig-args) @@ -1901,17 +1921,17 @@ (let ((var.lev (binding-value b= ))) (gen-ref src (car var.lev) (c= dr var.lev) maps))) (lambda (var maps) (values `(ref ,v= ar) maps))) - (if (ellipsis? e) + (if (ellipsis? e r mod) (syntax-violation 'syntax "mispla= ced ellipsis" src) (values `(quote ,e) maps))))) (syntax-case e () ((dots e) - (ellipsis? #'dots) - (gen-syntax src #'e r maps (lambda (x) #f)= mod)) + (ellipsis? #'dots r mod) + (gen-syntax src #'e r maps (lambda (e r mo= d) #f) mod)) ((x dots . y) ;; this could be about a dozen lines of co= de, except that we ;; choose to handle #'(x ... ...) forms - (ellipsis? #'dots) + (ellipsis? #'dots r mod) (let f ((y #'y) (k (lambda (maps) (call-with-values @@ -1926,7 +1946,7 @@ (cdr maps))))= )))) (syntax-case y () ((dots . y) - (ellipsis? #'dots) + (ellipsis? #'dots r mod) (f #'y (lambda (maps) (call-with-values @@ -2119,6 +2139,25 @@ #'((args e1 e2 ...) ...))) (_ (syntax-violation 'case-lambda "bad case-lambda*= " e))))) =20 + (global-extend 'core 'with-ellipsis + (lambda (e r w s mod) + (syntax-case e () + ((_ dots e1 e2 ...) + (id? #'dots) + (let ((id (if (symbol? #'dots) + '#{ $sc-ellipsis }# + (make-syntax-object '#{ $sc-ellipsis= }# + (syntax-object-w= rap #'dots) + (syntax-object-m= odule #'dots))))) + (let ((ids (list id)) + (labels (list (gen-label))) + (bindings (list (make-binding 'ellipsis (s= ource-wrap #'dots w s mod))))) + (let ((nw (make-binding-wrap ids labels w)) + (nr (extend-env labels bindings r))) + (expand-body #'(e1 e2 ...) (source-wrap e nw= s mod) nr nw mod))))) + (_ (syntax-violation 'with-ellipsis "bad syntax" + (source-wrap e w s mod)))))) + (global-extend 'core 'let (let () (define (expand-let e r w s mod constructor ids vals = exps) @@ -2338,7 +2377,7 @@ (define convert-pattern ;; accepts pattern & keys ;; returns $sc-dispatch pattern & ids - (lambda (pattern keys) + (lambda (pattern keys ellipsis?) (define cvt* (lambda (p* n ids) (syntax-case p* () @@ -2427,10 +2466,10 @@ (define gen-clause (lambda (x keys clauses r pat fender exp mod) (call-with-values - (lambda () (convert-pattern pat keys)) + (lambda () (convert-pattern pat keys (lambda = (e) (ellipsis? e r mod)))) (lambda (p pvars) (cond - ((not (and-map (lambda (x) (not (ellipsis? (= car x)))) pvars)) + ((not (and-map (lambda (x) (not (ellipsis? (= car x) r mod))) pvars)) (syntax-violation 'syntax-case "misplaced e= llipsis" pat)) ((not (distinct-bound-ids? (map car pvars))) (syntax-violation 'syntax-case "duplicate p= attern variable" pat)) @@ -2500,7 +2539,7 @@ (let ((e (source-wrap e w s mod))) (syntax-case e () ((_ val (key ...) m ...) - (if (and-map (lambda (x) (and (id? x) (not (el= lipsis? x)))) + (if (and-map (lambda (x) (and (id? x) (not (el= lipsis? x r mod)))) #'(key ...)) (let ((x (gen-var 'tmp))) ;; fat finger binding and references to = temp variable x @@ -2604,6 +2643,11 @@ ((syntax) (values 'pattern-variable value)) ((displaced-lexical) (values 'displaced-lexical #f)) ((global) (values 'global (cons value (cdr mod)))) + ((ellipsis) + (values 'ellipsis + (make-syntax-object (syntax-object-expression va= lue) + (anti-mark (syntax-object-wr= ap value)) + (syntax-object-module value)= ))) (else (values 'other #f)))))))) =20 (define (syntax-locally-bound-identifiers id) @@ -2797,25 +2841,35 @@ =20 (define-syntax syntax-rules (lambda (xx) + (define (expand-syntax-rules dots keys docstrings clauses) + (with-syntax + (((k ...) keys) + ((docstring ...) docstrings) + ((((keyword . pattern) template) ...) clauses)) + (with-syntax + ((form #'(lambda (x) + docstring ... ; optional docstring + #((macro-type . syntax-rules) + (patterns pattern ...)) ; embed patterns as proce= dure metadata + (syntax-case x (k ...) + ((dummy . pattern) #'template) + ...)))) + (if dots + (with-syntax ((dots dots)) + #'(with-ellipsis dots form)) + #'form)))) (syntax-case xx () ((_ (k ...) ((keyword . pattern) template) ...) - #'(lambda (x) - ;; embed patterns as procedure metadata - #((macro-type . syntax-rules) - (patterns pattern ...)) - (syntax-case x (k ...) - ((dummy . pattern) #'template) - ...))) + (expand-syntax-rules #f #'(k ...) #'() #'(((keyword . pattern) temp= late) ...))) ((_ (k ...) docstring ((keyword . pattern) template) ...) (string? (syntax->datum #'docstring)) - #'(lambda (x) - ;; the same, but allow a docstring - docstring - #((macro-type . syntax-rules) - (patterns pattern ...)) - (syntax-case x (k ...) - ((dummy . pattern) #'template) - ...)))))) + (expand-syntax-rules #f #'(k ...) #'(docstring) #'(((keyword . patt= ern) template) ...))) + ((_ dots (k ...) ((keyword . pattern) template) ...) + (identifier? #'dots) + (expand-syntax-rules #'dots #'(k ...) #'() #'(((keyword . pattern) = template) ...))) + ((_ dots (k ...) docstring ((keyword . pattern) template) ...) + (and (identifier? #'dots) (string? (syntax->datum #'docstring))) + (expand-syntax-rules #'dots #'(k ...) #'(docstring) #'(((keyword . = pattern) template) ...)))))) =20 (define-syntax define-syntax-rule (lambda (x) diff --git a/test-suite/tests/syntax.test b/test-suite/tests/syntax.test index 6fac0ba..142e2e5 100644 --- a/test-suite/tests/syntax.test +++ b/test-suite/tests/syntax.test @@ -1,7 +1,7 @@ ;;;; syntax.test --- test suite for Guile's syntactic forms -*- scheme = -*- ;;;; ;;;; Copyright (C) 2001, 2003, 2004, 2005, 2006, 2009, 2010, -;;;; 2011, 2012 Free Software Foundation, Inc. +;;;; 2011, 2012, 2013 Free Software Foundation, Inc. ;;;; ;;;; This library is free software; you can redistribute it and/or ;;;; modify it under the terms of the GNU Lesser General Public @@ -19,6 +19,7 @@ =20 (define-module (test-suite test-syntax) #:use-module (ice-9 regex) + #:use-module (ice-9 local-eval) #:use-module (test-suite lib)) =20 =20 @@ -1172,6 +1173,44 @@ (r 'outer)) #t))) =20 +(with-test-prefix "syntax-rules" + + (pass-if-equal "custom ellipsis within normal ellipsis" + '((((a x) (a y) (a =E2=80=A6)) + ((b x) (b y) (b =E2=80=A6)) + ((c x) (c y) (c =E2=80=A6))) + (((a x) (b x) (c x)) + ((a y) (b y) (c y)) + ((a =E2=80=A6) (b =E2=80=A6) (c =E2=80=A6)))) + (let () + (define-syntax foo + (syntax-rules () + ((_ y ...) + (syntax-rules =E2=80=A6 () + ((_ x =E2=80=A6) + '((((x y) ...) =E2=80=A6) + (((x y) =E2=80=A6) ...))))))) + (define-syntax bar (foo x y =E2=80=A6)) + (bar a b c))) + + (pass-if-equal "normal ellipsis within custom ellipsis" + '((((a x) (a y) (a z)) + ((b x) (b y) (b z)) + ((c x) (c y) (c z))) + (((a x) (b x) (c x)) + ((a y) (b y) (c y)) + ((a z) (b z) (c z)))) + (let () + (define-syntax foo + (syntax-rules =E2=80=A6 () + ((_ y =E2=80=A6) + (syntax-rules () + ((_ x ...) + '((((x y) =E2=80=A6) ...) + (((x y) ...) =E2=80=A6))))))) + (define-syntax bar (foo x y z)) + (bar a b c)))) + (with-test-prefix "syntax-case" =20=20=20 (pass-if-syntax-error "duplicate pattern variable" @@ -1225,6 +1264,71 @@ ((x ... y ... z ...) #f))) (interaction-environment))))) =20 +(with-test-prefix "with-ellipsis" + + (pass-if-equal "simple" + '(a 1 2 3) + (let () + (define-syntax define-quotation-macros + (lambda (x) + (syntax-case x () + ((_ (macro-name head-symbol) ...) + #'(begin (define-syntax macro-name + (lambda (x) + (with-ellipsis =E2=80=A6 + (syntax-case x () + ((_ x =E2=80=A6) + #'(quote (head-symbol x =E2=80=A6))))))) + ...))))) + (define-quotation-macros (quote-a a) (quote-b b)) + (quote-a 1 2 3))) + + (pass-if-equal "disables normal ellipsis" + '(a ...) + (let () + (define-syntax foo + (lambda (x) + (with-ellipsis =E2=80=A6 + (syntax-case x () + ((_) + #'(quote (a ...))))))) + (foo))) + + (pass-if-equal "doesn't affect ellipsis for generated code" + '(a b c) + (let () + (define-syntax quotation-macro + (lambda (x) + (with-ellipsis =E2=80=A6 + (syntax-case x () + ((_) + #'(lambda (x) + (syntax-case x () + ((_ x ...) + #'(quote (x ...)))))))))) + (define-syntax kwote (quotation-macro)) + (kwote a b c))) + + (pass-if-equal "doesn't propagate into syntax binders" + '(a b c) + (let () + (with-ellipsis =E2=80=A6 + (define-syntax kwote + (lambda (x) + (syntax-case x () + ((_ x ...) + #'(quote (x ...)))))) + (kwote a b c)))) + + (pass-if-equal "works with local-eval" + 5 + (let ((env (with-ellipsis =E2=80=A6 (the-environment)))) + (local-eval '(syntax-case #'(a b c d e) () + ((x =E2=80=A6) + (length #'(x =E2=80=A6)))) + env)))) + ;;; Local Variables: ;;; eval: (put 'pass-if-syntax-error 'scheme-indent-function 1) +;;; eval: (put 'with-ellipsis 'scheme-indent-function 1) ;;; End: --=20 1.7.5.4 --=-=-=--