diff --git a/AUTHORS b/AUTHORS index f31762bf..5ee0030b 100644 --- a/AUTHORS +++ b/AUTHORS @@ -22,3 +22,6 @@ module/mes/lalr.upstream.mes Portable syntax-case from Chez Scheme module/mes/psyntax.ss module/mes/psyntax-pp.mes [generated] + +Optargs from Guile +module/mes/optargs.upstream.mes diff --git a/GNUmakefile b/GNUmakefile index 69be3c2b..65c6c168 100644 --- a/GNUmakefile +++ b/GNUmakefile @@ -57,6 +57,7 @@ TESTS:=\ tests/vector.test\ tests/scm.test\ tests/cwv.test\ + tests/optargs.test\ tests/psyntax.test\ tests/let-syntax.test\ tests/record.test\ diff --git a/NEWS b/NEWS index 4b219662..3a42bd96 100644 --- a/NEWS +++ b/NEWS @@ -19,6 +19,7 @@ block-comments are all handled by the Scheme reader later. ** Language *** Keywords are supported. *** Cond now supports =>. +*** Lambda* and define* are now supported. * Changes in 0.3 since 0.2 ** Core *** Number-based rather than pointer-based cells. diff --git a/module/mes/optargs.mes b/module/mes/optargs.mes new file mode 100644 index 00000000..0b8db04b --- /dev/null +++ b/module/mes/optargs.mes @@ -0,0 +1,34 @@ +;;; -*-scheme-*- + +;;; Mes --- Maxwell Equations of Software +;;; Copyright © 2016 Jan Nieuwenhuizen +;;; +;;; This file is part of Mes. +;;; +;;; Mes 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. +;;; +;;; Mes 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 Mes. If not, see . + +;;; Commentary: + +;;; Optargs (define*, lambda* et al.) from Guile + +;;; Code: + +(mes-use-module (mes scm)) + +(define-macro (defmacro name args . body) + `(define-macro ,(cons name args) ,@body)) + +(define-macro (set-procedure-property! proc key value) + proc) +(mes-use-module (mes optargs.upstream)) diff --git a/module/mes/optargs.upstream.mes b/module/mes/optargs.upstream.mes new file mode 100644 index 00000000..8f495cd2 --- /dev/null +++ b/module/mes/optargs.upstream.mes @@ -0,0 +1,500 @@ +;;;; optargs.scm -- support for optional arguments +;;;; +;;;; Copyright (C) 1997, 1998, 1999, 2001, 2002, 2004, 2006 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 +;;;; License as published by the Free Software Foundation; either +;;;; version 3 of the License, or (at your option) any later version. +;;;; +;;;; This library 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 +;;;; Lesser General Public License for more details. +;;;; +;;;; You should have received a copy of the GNU Lesser General Public +;;;; License along with this library; if not, write to the Free Software +;;;; Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA +;;;; +;;;; Contributed by Maciej Stachowiak + + + +;;; Commentary: + +;;; {Optional Arguments} +;;; +;;; The C interface for creating Guile procedures has a very handy +;;; "optional argument" feature. This module attempts to provide +;;; similar functionality for procedures defined in Scheme with +;;; a convenient and attractive syntax. +;;; +;;; exported macros are: +;;; let-optional +;;; let-optional* +;;; let-keywords +;;; let-keywords* +;;; lambda* +;;; define* +;;; define*-public +;;; defmacro* +;;; defmacro*-public +;;; +;;; +;;; Summary of the lambda* extended parameter list syntax (brackets +;;; are used to indicate grouping only): +;;; +;;; ext-param-list ::= [identifier]* [#:optional [ext-var-decl]+]? +;;; [#:key [ext-var-decl]+ [#:allow-other-keys]?]? +;;; [[#:rest identifier]|[. identifier]]? +;;; +;;; ext-var-decl ::= identifier | ( identifier expression ) +;;; +;;; The characters `*', `+' and `?' are not to be taken literally; they +;;; mean respectively, zero or more occurences, one or more occurences, +;;; and one or zero occurences. +;;; + +;;; Code: + +;; (define-module (ice-9 optargs) +;; #:use-module (system base pmatch) +;; #:replace (lambda*) +;; #:export-syntax (let-optional +;; let-optional* +;; let-keywords +;; let-keywords* +;; define* +;; define*-public +;; defmacro* +;; defmacro*-public)) + +;; let-optional rest-arg (binding ...) . body +;; let-optional* rest-arg (binding ...) . body +;; macros used to bind optional arguments +;; +;; These two macros give you an optional argument interface that is +;; very "Schemey" and introduces no fancy syntax. They are compatible +;; with the scsh macros of the same name, but are slightly +;; extended. Each of binding may be of one of the forms or +;; ( ). rest-arg should be the rest-argument of +;; the procedures these are used from. The items in rest-arg are +;; sequentially bound to the variable namess are given. When rest-arg +;; runs out, the remaining vars are bound either to the default values +;; or to `#f' if no default value was specified. rest-arg remains +;; bound to whatever may have been left of rest-arg. +;; + +(defmacro let-optional (REST-ARG BINDINGS . BODY) + (let-optional-template REST-ARG BINDINGS BODY 'let)) + +(defmacro let-optional* (REST-ARG BINDINGS . BODY) + (let-optional-template REST-ARG BINDINGS BODY 'let*)) + + + +;; let-keywords rest-arg allow-other-keys? (binding ...) . body +;; let-keywords* rest-arg allow-other-keys? (binding ...) . body +;; macros used to bind keyword arguments +;; +;; These macros pick out keyword arguments from rest-arg, but do not +;; modify it. This is consistent at least with Common Lisp, which +;; duplicates keyword args in the rest arg. More explanation of what +;; keyword arguments in a lambda list look like can be found below in +;; the documentation for lambda*. Bindings can have the same form as +;; for let-optional. If allow-other-keys? is false, an error will be +;; thrown if anything that looks like a keyword argument but does not +;; match a known keyword parameter will result in an error. +;; + + +(defmacro let-keywords (REST-ARG ALLOW-OTHER-KEYS? BINDINGS . BODY) + (let-keywords-template REST-ARG ALLOW-OTHER-KEYS? BINDINGS BODY 'let)) + +(defmacro let-keywords* (REST-ARG ALLOW-OTHER-KEYS? BINDINGS . BODY) + (let-keywords-template REST-ARG ALLOW-OTHER-KEYS? BINDINGS BODY 'let*)) + + +;; some utility procedures for implementing the various let-forms. + +(define (let-o-k-template REST-ARG BINDINGS BODY let-type proc) + (let ((bindings (map (lambda (x) + (if (list? x) + x + (list x #f))) + BINDINGS))) + `(,let-type ,(map proc bindings) ,@BODY))) + +(define (let-optional-template REST-ARG BINDINGS BODY let-type) + (if (null? BINDINGS) + `(let () ,@BODY) + (let-o-k-template REST-ARG BINDINGS BODY let-type + (lambda (optional) + `(,(car optional) + (cond + ((not (null? ,REST-ARG)) + (let ((result (car ,REST-ARG))) + ,(list 'set! REST-ARG + `(cdr ,REST-ARG)) + result)) + (else + ,(cadr optional)))))))) + +(define (let-keywords-template REST-ARG ALLOW-OTHER-KEYS? BINDINGS BODY let-type) + (if (null? BINDINGS) + `(let () ,@BODY) + (let* ((kb-list-gensym (gensym "kb:G")) + (bindfilter (lambda (key) + `(,(car key) + (cond + ((assq ',(car key) ,kb-list-gensym) + => cdr) + (else + ,(cadr key))))))) + `(let ((,kb-list-gensym (;;(@@ (ice-9 optargs) rest-arg->keyword-binding-list) + rest-arg->keyword-binding-list + ,REST-ARG ',(map (lambda (x) (symbol->keyword (if (pair? x) (car x) x))) + BINDINGS) + ,ALLOW-OTHER-KEYS?))) + ,(let-o-k-template REST-ARG BINDINGS BODY let-type bindfilter))))) + + +(define (rest-arg->keyword-binding-list rest-arg keywords allow-other-keys?) + (if (null? rest-arg) + '() + (let loop ((first (car rest-arg)) + (rest (cdr rest-arg)) + (accum '())) + (let ((next (lambda (a) + (if (null? (cdr rest)) + a + (loop (cadr rest) (cddr rest) a))))) + (if (keyword? first) + (cond + ((memq first keywords) + (if (null? rest) + (error "Keyword argument has no value.") + (next (cons (cons (keyword->symbol first) + (car rest)) accum)))) + ((not allow-other-keys?) + (error "Unknown keyword in arguments.")) + (else (if (null? rest) + accum + (next accum)))) + (if (null? rest) + accum + (loop (car rest) (cdr rest) accum))))))) + + +;; lambda* args . body +;; lambda extended for optional and keyword arguments +;; +;; lambda* creates a procedure that takes optional arguments. These +;; are specified by putting them inside brackets at the end of the +;; paramater list, but before any dotted rest argument. For example, +;; (lambda* (a b #:optional c d . e) '()) +;; creates a procedure with fixed arguments a and b, optional arguments c +;; and d, and rest argument e. If the optional arguments are omitted +;; in a call, the variables for them are bound to `#f'. +;; +;; lambda* can also take keyword arguments. For example, a procedure +;; defined like this: +;; (lambda* (#:key xyzzy larch) '()) +;; can be called with any of the argument lists (#:xyzzy 11) +;; (#:larch 13) (#:larch 42 #:xyzzy 19) (). Whichever arguments +;; are given as keywords are bound to values. +;; +;; Optional and keyword arguments can also be given default values +;; which they take on when they are not present in a call, by giving a +;; two-item list in place of an optional argument, for example in: +;; (lambda* (foo #:optional (bar 42) #:key (baz 73)) (list foo bar baz)) +;; foo is a fixed argument, bar is an optional argument with default +;; value 42, and baz is a keyword argument with default value 73. +;; Default value expressions are not evaluated unless they are needed +;; and until the procedure is called. +;; +;; lambda* now supports two more special parameter list keywords. +;; +;; lambda*-defined procedures now throw an error by default if a +;; keyword other than one of those specified is found in the actual +;; passed arguments. However, specifying #:allow-other-keys +;; immediately after the keyword argument declarations restores the +;; previous behavior of ignoring unknown keywords. lambda* also now +;; guarantees that if the same keyword is passed more than once, the +;; last one passed is the one that takes effect. For example, +;; ((lambda* (#:key (heads 0) (tails 0)) (display (list heads tails))) +;; #:heads 37 #:tails 42 #:heads 99) +;; would result in (99 47) being displayed. +;; +;; #:rest is also now provided as a synonym for the dotted syntax rest +;; argument. The argument lists (a . b) and (a #:rest b) are equivalent in +;; all respects to lambda*. This is provided for more similarity to DSSSL, +;; MIT-Scheme and Kawa among others, as well as for refugees from other +;; Lisp dialects. + + +(defmacro lambda* (ARGLIST . BODY) + (parse-arglist + ARGLIST + (lambda (non-optional-args optionals keys aok? rest-arg) + ;; Check for syntax errors. + (if (not (every? symbol? non-optional-args)) + (error "Syntax error in fixed argument declaration.")) + (if (not (every? ext-decl? optionals)) + (error "Syntax error in optional argument declaration.")) + (if (not (every? ext-decl? keys)) + (error "Syntax error in keyword argument declaration.")) + (if (not (or (symbol? rest-arg) (eq? #f rest-arg))) + (error "Syntax error in rest argument declaration.")) + ;; generate the code. + (let ((rest-gensym (or rest-arg (gensym "lambda*:G"))) + (lambda-gensym (gensym "lambda*:L"))) + (if (not (and (null? optionals) (null? keys))) + `(let ((,lambda-gensym + (lambda (,@non-optional-args . ,rest-gensym) + ;; Make sure that if the proc had a docstring, we put it + ;; here where it will be visible. + ,@(if (and (not (null? BODY)) + (string? (car BODY))) + (list (car BODY)) + '()) + (let-optional* + ,rest-gensym + ,optionals + (let-keywords* ,rest-gensym + ,aok? + ,keys + ,@(if (and (not rest-arg) (null? keys)) + `((if (not (null? ,rest-gensym)) + (error "Too many arguments."))) + '()) + (let () + ,@BODY)))))) + (set-procedure-property! ,lambda-gensym 'arglist + '(,non-optional-args + ,optionals + ,keys + ,aok? + ,rest-arg)) + ,lambda-gensym) + `(lambda (,@non-optional-args . ,(if rest-arg rest-arg '())) + ,@BODY)))))) + + +(define (every? pred lst) + (or (null? lst) + (and (pred (car lst)) + (every? pred (cdr lst))))) + +(define (ext-decl? obj) + (or (symbol? obj) + (and (list? obj) (= 2 (length obj)) (symbol? (car obj))))) + +;; XXX - not tail recursive +(define (improper-list-copy obj) + (if (pair? obj) + (cons (car obj) (improper-list-copy (cdr obj))) + obj)) + +(define (parse-arglist arglist cont) + (define (split-list-at val lst cont) + (cond + ((memq val lst) + => (lambda (pos) + (if (memq val (cdr pos)) + (error (with-output-to-string + (lambda () + (map display `(,val + " specified more than once in argument list."))))) + (cont (reverse (cdr (memq val (reverse lst)))) (cdr pos) #t)))) + (else (cont lst '() #f)))) + (define (parse-opt-and-fixed arglist keys aok? rest cont) + (split-list-at + #:optional arglist + (lambda (before after split?) + (if (and split? (null? after)) + (error "#:optional specified but no optional arguments declared.") + (cont before after keys aok? rest))))) + (define (parse-keys arglist rest cont) + (split-list-at + #:allow-other-keys arglist + (lambda (aok-before aok-after aok-split?) + (if (and aok-split? (not (null? aok-after))) + (error "#:allow-other-keys not at end of keyword argument declarations.") + (split-list-at + #:key aok-before + (lambda (key-before key-after key-split?) + (cond + ((and aok-split? (not key-split?)) + (error "#:allow-other-keys specified but no keyword arguments declared.")) + (key-split? + (cond + ((null? key-after) (error "#:key specified but no keyword arguments declared.")) + ((memq #:optional key-after) (error "#:optional arguments declared after #:key arguments.")) + (else (parse-opt-and-fixed key-before key-after aok-split? rest cont)))) + (else (parse-opt-and-fixed arglist '() #f rest cont))))))))) + (define (parse-rest arglist cont) + (cond + ((null? arglist) (cont '() '() '() #f #f)) + ((not (pair? arglist)) (cont '() '() '() #f arglist)) + ((not (list? arglist)) + (let* ((copy (improper-list-copy arglist)) + (lp (last-pair copy)) + (ra (cdr lp))) + (set-cdr! lp '()) + (if (memq #:rest copy) + (error "Cannot specify both #:rest and dotted rest argument.") + (parse-keys copy ra cont)))) + (else (split-list-at + #:rest arglist + (lambda (before after split?) + (if split? + (case (length after) + ((0) (error "#:rest not followed by argument.")) + ((1) (parse-keys before (car after) cont)) + (else (error "#:rest argument must be declared last."))) + (parse-keys before #f cont))))))) + + (parse-rest arglist cont)) + + + +;; define* args . body +;; define*-public args . body +;; define and define-public extended for optional and keyword arguments +;; +;; define* and define*-public support optional arguments with +;; a similar syntax to lambda*. They also support arbitrary-depth +;; currying, just like Guile's define. Some examples: +;; (define* (x y #:optional a (z 3) #:key w . u) (display (list y z u))) +;; defines a procedure x with a fixed argument y, an optional agument +;; a, another optional argument z with default value 3, a keyword argument w, +;; and a rest argument u. +;; (define-public* ((foo #:optional bar) #:optional baz) '()) +;; This illustrates currying. A procedure foo is defined, which, +;; when called with an optional argument bar, returns a procedure that +;; takes an optional argument baz. +;; +;; Of course, define*[-public] also supports #:rest and #:allow-other-keys +;; in the same way as lambda*. + +(defmacro define* (ARGLIST . BODY) + (define*-guts 'define ARGLIST BODY)) + +(defmacro define*-public (ARGLIST . BODY) + (define*-guts 'define-public ARGLIST BODY)) + +;; The guts of define* and define*-public. +(define (define*-guts DT ARGLIST BODY) + (define (nest-lambda*s arglists) + (if (null? arglists) + BODY + `((lambda* ,(car arglists) ,@(nest-lambda*s (cdr arglists)))))) + (define (define*-guts-helper ARGLIST arglists) + (let ((first (car ARGLIST)) + (al (cons (cdr ARGLIST) arglists))) + (if (symbol? first) + `(,DT ,first ,@(nest-lambda*s al)) + (define*-guts-helper first al)))) + (if (symbol? ARGLIST) + `(,DT ,ARGLIST ,@BODY) + (define*-guts-helper ARGLIST '()))) + + + +;; defmacro* name args . body +;; defmacro*-public args . body +;; defmacro and defmacro-public extended for optional and keyword arguments +;; +;; These are just like defmacro and defmacro-public except that they +;; take lambda*-style extended paramter lists, where #:optional, +;; #:key, #:allow-other-keys and #:rest are allowed with the usual +;; semantics. Here is an example of a macro with an optional argument: +;; (defmacro* transmorgify (a #:optional b) + +(defmacro defmacro* (NAME ARGLIST . BODY) + `(define-macro ,NAME #f (lambda* ,ARGLIST ,@BODY))) + +(defmacro defmacro*-public (NAME ARGLIST . BODY) + `(begin + (defmacro* ,NAME ,ARGLIST ,@BODY) + (export-syntax ,NAME))) + +;;; Support for optional & keyword args with the interpreter. +(define *uninitialized* (list 'uninitialized)) +(define (parse-lambda-case spec inits predicate args) + (pmatch spec + ((,nreq ,nopt ,rest-idx ,nargs ,allow-other-keys? ,kw-indices) + (define (req args prev tail n) + (cond + ((zero? n) + (if prev (set-cdr! prev '())) + (let ((slots-tail (make-list (- nargs nreq) *uninitialized*))) + (opt (if prev (append! args slots-tail) slots-tail) + slots-tail tail nopt inits))) + ((null? tail) + #f) ;; fail + (else + (req args tail (cdr tail) (1- n))))) + (define (opt slots slots-tail args-tail n inits) + (cond + ((zero? n) + (rest-or-key slots slots-tail args-tail inits rest-idx)) + ((null? args-tail) + (set-car! slots-tail (apply (car inits) slots)) + (opt slots (cdr slots-tail) '() (1- n) (cdr inits))) + (else + (set-car! slots-tail (car args-tail)) + (opt slots (cdr slots-tail) (cdr args-tail) (1- n) (cdr inits))))) + (define (rest-or-key slots slots-tail args-tail inits rest-idx) + (cond + (rest-idx + ;; it has to be this way, vars are allocated in this order + (set-car! slots-tail args-tail) + (if (pair? kw-indices) + (key slots (cdr slots-tail) args-tail inits) + (rest-or-key slots (cdr slots-tail) '() inits #f))) + ((pair? kw-indices) + ;; fail early here, because once we're in keyword land we throw + ;; errors instead of failing + (and (or (null? args-tail) rest-idx (keyword? (car args-tail))) + (key slots slots-tail args-tail inits))) + ((pair? args-tail) + #f) ;; fail + (else + (pred slots)))) + (define (key slots slots-tail args-tail inits) + (cond + ((null? args-tail) + (if (null? inits) + (pred slots) + (begin + (if (eq? (car slots-tail) *uninitialized*) + (set-car! slots-tail (apply (car inits) slots))) + (key slots (cdr slots-tail) '() (cdr inits))))) + ((not (keyword? (car args-tail))) + (if rest-idx + ;; no error checking, everything goes to the rest.. + (key slots slots-tail '() inits) + (error "bad keyword argument list" args-tail))) + ((and (keyword? (car args-tail)) + (pair? (cdr args-tail)) + (assq-ref kw-indices (car args-tail))) + => (lambda (i) + (list-set! slots i (cadr args-tail)) + (key slots slots-tail (cddr args-tail) inits))) + ((and (keyword? (car args-tail)) + (pair? (cdr args-tail)) + allow-other-keys?) + (key slots slots-tail (cddr args-tail) inits)) + (else (error "unrecognized keyword" args-tail)))) + (define (pred slots) + (cond + (predicate + (if (apply predicate slots) + slots + #f)) + (else slots))) + (let ((args (list-copy args))) + (req args #f args nreq))) + (else (error "unexpected spec" spec)))) diff --git a/tests/optargs.test b/tests/optargs.test new file mode 100755 index 00000000..4e130e7d --- /dev/null +++ b/tests/optargs.test @@ -0,0 +1,54 @@ +#! /bin/sh +# -*-scheme-*- +echo ' ()' | cat $(dirname $0)/../module/mes/base-0.mes $0 /dev/stdin | $(dirname $0)/../scripts/mes $MES_FLAGS "$@" +#paredit:|| +exit $? +!# + +;;; -*-scheme-*- + +;;; Mes --- Maxwell Equations of Software +;;; Copyright © 2016 Jan Nieuwenhuizen +;;; +;;; This file is part of Mes. +;;; +;;; Mes 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. +;;; +;;; Mes 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 Mes. If not, see . + +(mes-use-module (mes optargs)) +(mes-use-module (mes test)) + +(pass-if-equal "cond =>" 10 + (cond + (5 => (lambda (p) (* p 2))))) +(pass-if-equal "cond => 2" 10 + (cond + (#f (display "hallo") (newline)) + (5 => (lambda (p) (* p 2))) + (#t (display "wereld" (newline))))) +(pass-if-equal "cond => last" 10 + (cond + (#f (display "hallo") (newline)) + (5 => (lambda (p) (* p 2))))) + +(pass-if "keyword?" (keyword? #:foo)) +(pass-if "keywords" (eq? #:foo #:foo)) +(pass-if-equal "keyword->symbol" 'foo (keyword->symbol #:foo)) +(pass-if-equal "symbol->keyword" #:foo (symbol->keyword 'foo)) +(pass-if-not "keywords" (eq? #:foo ':foo)) +(pass-if "optargs #:optional" ((lambda* (#:optional (x #f)) x) #t)) +(pass-if-equal "optargs #:optional default" #f ((lambda* (#:optional (x #f)) x))) +(pass-if "optargs key" ((lambda* (#:key (foo #f)) foo) #:foo #t)) +(pass-if-equal "optargs key default" #f ((lambda* (#:key (foo #f)) foo))) + +(result 'report)