3 ;;;; Copyright (C) 2001, 2003, 2006, 2009, 2010, 2011,
4 ;;;; 2012, 2013 Free Software Foundation, Inc.
6 ;;;; This library is free software; you can redistribute it and/or
7 ;;;; modify it under the terms of the GNU Lesser General Public
8 ;;;; License as published by the Free Software Foundation; either
9 ;;;; version 3 of the License, or (at your option) any later version.
11 ;;;; This library is distributed in the hope that it will be useful,
12 ;;;; but WITHOUT ANY WARRANTY; without even the implied warranty of
13 ;;;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
14 ;;;; Lesser General Public License for more details.
16 ;;;; You should have received a copy of the GNU Lesser General Public
17 ;;;; License along with this library; if not, write to the Free Software
18 ;;;; Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
22 ;;; Portable implementation of syntax-case
23 ;;; Originally extracted from Chez Scheme Version 5.9f
24 ;;; Authors: R. Kent Dybvig, Oscar Waddell, Bob Hieb, Carl Bruggeman
26 ;;; Copyright (c) 1992-1997 Cadence Research Systems
27 ;;; Permission to copy this software, in whole or in part, to use this
28 ;;; software for any lawful purpose, and to redistribute this software
29 ;;; is granted subject to the restriction that all copies made of this
30 ;;; software must include this copyright notice in full. This software
31 ;;; is provided AS IS, with NO WARRANTY, EITHER EXPRESS OR IMPLIED,
32 ;;; INCLUDING BUT NOT LIMITED TO IMPLIED WARRANTIES OF MERCHANTABILITY
33 ;;; OR FITNESS FOR ANY PARTICULAR PURPOSE. IN NO EVENT SHALL THE
34 ;;; AUTHORS BE LIABLE FOR CONSEQUENTIAL OR INCIDENTAL DAMAGES OF ANY
35 ;;; NATURE WHATSOEVER.
37 ;;; Modified by Mikael Djurfeldt <djurfeldt@nada.kth.se> according
38 ;;; to the ChangeLog distributed in the same directory as this file:
39 ;;; 1997-08-19, 1997-09-03, 1997-09-10, 2000-08-13, 2000-08-24,
40 ;;; 2000-09-12, 2001-03-08
42 ;;; Modified by Andy Wingo <wingo@pobox.com> according to the Git
43 ;;; revision control logs corresponding to this file: 2009, 2010.
46 ;;; This code is based on "Syntax Abstraction in Scheme"
47 ;;; by R. Kent Dybvig, Robert Hieb, and Carl Bruggeman.
48 ;;; Lisp and Symbolic Computation 5:4, 295-326, 1992.
49 ;;; <http://www.cs.indiana.edu/~dyb/pubs/LaSC-5-4-pp295-326.pdf>
52 ;;; This file defines the syntax-case expander, macroexpand, and a set
53 ;;; of associated syntactic forms and procedures. Of these, the
54 ;;; following are documented in The Scheme Programming Language,
55 ;;; Fourth Edition (R. Kent Dybvig, MIT Press, 2009), and in the
58 ;;; bound-identifier=?
61 ;;; syntax-parameterize
63 ;;; generate-temporaries
74 ;;; Additionally, the expander provides definitions for a number of core
75 ;;; Scheme syntactic bindings, such as `let', `lambda', and the like.
77 ;;; The remaining exports are listed below:
79 ;;; (macroexpand datum)
80 ;;; if datum represents a valid expression, macroexpand returns an
81 ;;; expanded version of datum in a core language that includes no
82 ;;; syntactic abstractions. The core language includes begin,
83 ;;; define, if, lambda, letrec, quote, and set!.
84 ;;; (eval-when situations expr ...)
85 ;;; conditionally evaluates expr ... at compile-time or run-time
86 ;;; depending upon situations (see the Chez Scheme System Manual,
87 ;;; Revision 3, for a complete description)
88 ;;; (syntax-violation who message form [subform])
89 ;;; used to report errors found during expansion
90 ;;; ($sc-dispatch e p)
91 ;;; used by expanded code to handle syntax-case matching
93 ;;; This file is shipped along with an expanded version of itself,
94 ;;; psyntax-pp.scm, which is loaded when psyntax.scm has not yet been
95 ;;; compiled. In this way, psyntax bootstraps off of an expanded
96 ;;; version of itself.
98 ;;; This implementation of the expander sometimes uses syntactic
99 ;;; abstractions when procedural abstractions would suffice. For
100 ;;; example, we define top-wrap and top-marked? as
102 ;;; (define-syntax top-wrap (identifier-syntax '((top))))
103 ;;; (define-syntax top-marked?
105 ;;; ((_ w) (memq 'top (wrap-marks w)))))
109 ;;; (define top-wrap '((top)))
110 ;;; (define top-marked?
111 ;;; (lambda (w) (memq 'top (wrap-marks w))))
113 ;;; On the other hand, we don't do this consistently; we define
114 ;;; make-wrap, wrap-marks, and wrap-subst simply as
116 ;;; (define make-wrap cons)
117 ;;; (define wrap-marks car)
118 ;;; (define wrap-subst cdr)
120 ;;; In Chez Scheme, the syntactic and procedural forms of these
121 ;;; abstractions are equivalent, since the optimizer consistently
122 ;;; integrates constants and small procedures. This will be true of
123 ;;; Guile as well, once we implement a proper inliner.
126 ;;; Implementation notes:
128 ;;; Objects with no standard print syntax, including objects containing
129 ;;; cycles and syntax object, are allowed in quoted data as long as they
130 ;;; are contained within a syntax form or produced by datum->syntax.
131 ;;; Such objects are never copied.
133 ;;; All identifiers that don't have macro definitions and are not bound
134 ;;; lexically are assumed to be global variables.
136 ;;; Top-level definitions of macro-introduced identifiers are allowed.
137 ;;; This may not be appropriate for implementations in which the
138 ;;; model is that bindings are created by definitions, as opposed to
139 ;;; one in which initial values are assigned by definitions.
141 ;;; Identifiers and syntax objects are implemented as vectors for
142 ;;; portability. As a result, it is possible to "forge" syntax objects.
144 ;;; The implementation of generate-temporaries assumes that it is
145 ;;; possible to generate globally unique symbols (gensyms).
147 ;;; The source location associated with incoming expressions is tracked
148 ;;; via the source-properties mechanism, a weak map from expression to
149 ;;; source information. At times the source is separated from the
150 ;;; expression; see the note below about "efficiency and confusion".
155 ;;; When changing syntax-object representations, it is necessary to support
156 ;;; both old and new syntax-object representations in id-var-name. It
157 ;;; should be sufficient to recognize old representations and treat
158 ;;; them as not lexically bound.
163 (set-current-module (resolve-module '(guile))))
166 (define-syntax define-expansion-constructors
170 (let lp ((n 0) (out '()))
171 (if (< n (vector-length %expanded-vtables))
173 (let* ((vtable (vector-ref %expanded-vtables n))
174 (stem (struct-ref vtable (+ vtable-offset-user 0)))
175 (fields (struct-ref vtable (+ vtable-offset-user 2)))
176 (sfields (map (lambda (f) (datum->syntax x f)) fields))
177 (ctor (datum->syntax x (symbol-append 'make- stem))))
178 (cons #`(define (#,ctor #,@sfields)
179 (make-struct (vector-ref %expanded-vtables #,n) 0
182 #`(begin #,@(reverse out))))))))
184 (define-syntax define-expansion-accessors
189 (let ((vtable (vector-ref %expanded-vtables n))
190 (stem (syntax->datum #'stem)))
191 (if (eq? (struct-ref vtable (+ vtable-offset-user 0)) stem)
193 (define (#,(datum->syntax x (symbol-append stem '?)) x)
195 (eq? (struct-vtable x)
196 (vector-ref %expanded-vtables #,n))))
199 (let ((get (datum->syntax x (symbol-append stem '- f)))
200 (set (datum->syntax x (symbol-append 'set- stem '- f '!)))
201 (idx (list-index (struct-ref vtable
202 (+ vtable-offset-user 2))
206 (struct-ref x #,idx))
208 (struct-set! x #,idx v)))))
209 (syntax->datum #'(field ...))))
212 (define-syntax define-structure
214 (define construct-name
215 (lambda (template-identifier . args)
223 (symbol->string (syntax->datum x))))
227 (and-map identifier? #'(name id1 ...))
229 ((constructor (construct-name #'name "make-" #'name))
230 (predicate (construct-name #'name #'name "?"))
232 (map (lambda (x) (construct-name x #'name "-" x))
236 (construct-name x "set-" #'name "-" x "!"))
239 (+ (length #'(id1 ...)) 1))
241 (let f ((i 1) (ids #'(id1 ...)))
244 (cons i (f (+ i 1) (cdr ids)))))))
248 (vector 'name id1 ... )))
252 (= (vector-length x) structure-length)
253 (eq? (vector-ref x 0) 'name))))
256 (vector-ref x index)))
260 (vector-set! x index update)))
264 (define-expansion-constructors)
265 (define-expansion-accessors lambda meta)
267 ;; hooks to nonportable run-time helpers
269 (define-syntax fx+ (identifier-syntax +))
270 (define-syntax fx- (identifier-syntax -))
271 (define-syntax fx= (identifier-syntax =))
272 (define-syntax fx< (identifier-syntax <))
274 (define top-level-eval-hook
278 (define local-eval-hook
282 ;; Capture syntax-session-id before we shove it off into a module.
284 (let ((v (module-variable (current-module) 'syntax-session-id)))
286 ((variable-ref v)))))
288 (define put-global-definition-hook
289 (lambda (symbol type val)
290 (module-define! (current-module)
292 (make-syntax-transformer symbol type val))))
294 (define get-global-definition-hook
295 (lambda (symbol module)
296 (if (and (not module) (current-module))
297 (warn "module system is booted, we should have a module" symbol))
298 (let ((v (module-variable (if module
299 (resolve-module (cdr module))
302 (and v (variable-bound? v)
303 (let ((val (variable-ref v)))
304 (and (macro? val) (macro-type val)
305 (cons (macro-type val)
306 (macro-binding val)))))))))
309 (define (decorate-source e s)
310 (if (and s (supports-source-properties? e))
311 (set-source-properties! e s))
314 (define (maybe-name-value! name val)
316 (let ((meta (lambda-meta val)))
317 (if (not (assq 'name meta))
318 (set-lambda-meta! val (acons 'name name meta))))))
320 ;; output constructors
325 (define build-application
326 (lambda (source fun-exp arg-exps)
327 (make-application source fun-exp arg-exps)))
329 (define build-conditional
330 (lambda (source test-exp then-exp else-exp)
331 (make-conditional source test-exp then-exp else-exp)))
334 (lambda (source fluids vals body)
335 (make-dynlet source fluids vals body)))
337 (define build-lexical-reference
338 (lambda (type source name var)
339 (make-lexical-ref source name var)))
341 (define build-lexical-assignment
342 (lambda (source name var exp)
343 (maybe-name-value! name exp)
344 (make-lexical-set source name var exp)))
346 (define (analyze-variable mod var modref-cont bare-cont)
349 (let ((kind (car mod))
352 ((public) (modref-cont mod var #t))
353 ((private) (if (not (equal? mod (module-name (current-module))))
354 (modref-cont mod var #f)
356 ((bare) (bare-cont var))
357 ((hygiene) (if (and (not (equal? mod (module-name (current-module))))
358 (module-variable (resolve-module mod) var))
359 (modref-cont mod var #f)
361 (else (syntax-violation #f "bad module kind" var mod))))))
363 (define build-global-reference
364 (lambda (source var mod)
367 (lambda (mod var public?)
368 (make-module-ref source mod var public?))
370 (make-toplevel-ref source var)))))
372 (define build-global-assignment
373 (lambda (source var exp mod)
374 (maybe-name-value! var exp)
377 (lambda (mod var public?)
378 (make-module-set source mod var public? exp))
380 (make-toplevel-set source var exp)))))
382 (define build-global-definition
383 (lambda (source var exp)
384 (maybe-name-value! var exp)
385 (make-toplevel-define source var exp)))
387 (define build-simple-lambda
388 (lambda (src req rest vars meta exp)
391 ;; hah, a case in which kwargs would be nice.
393 ;; src req opt rest kw inits vars body else
394 src req #f rest #f '() vars exp #f))))
396 (define build-case-lambda
397 (lambda (src meta body)
398 (make-lambda src meta body)))
400 (define build-lambda-case
402 ;; opt := (name ...) | #f
404 ;; kw := (allow-other-keys? (keyword name var) ...) | #f
407 ;; vars map to named arguments in the following order:
408 ;; required, optional (positional), rest, keyword.
409 ;; the body of a lambda: anything, already expanded
410 ;; else: lambda-case | #f
411 (lambda (src req opt rest kw inits vars body else-case)
412 (make-lambda-case src req opt rest kw inits vars body else-case)))
414 (define build-primref
416 (if (equal? (module-name (current-module)) '(guile))
417 (make-toplevel-ref src name)
418 (make-module-ref src '(guile) name #f))))
420 (define (build-data src exp)
421 (make-const src exp))
423 (define build-sequence
425 (if (null? (cdr exps))
427 (make-sequence src exps))))
430 (lambda (src ids vars val-exps body-exp)
431 (for-each maybe-name-value! ids val-exps)
434 (make-let src ids vars val-exps body-exp))))
436 (define build-named-let
437 (lambda (src ids vars val-exps body-exp)
442 (let ((proc (build-simple-lambda src ids #f vars '() body-exp)))
443 (maybe-name-value! f-name proc)
444 (for-each maybe-name-value! ids val-exps)
447 (list f-name) (list f) (list proc)
448 (build-application src (build-lexical-reference 'fun src f-name f)
452 (lambda (src in-order? ids vars val-exps body-exp)
456 (for-each maybe-name-value! ids val-exps)
457 (make-letrec src in-order? ids vars val-exps body-exp)))))
460 ;; FIXME: use a faster gensym
461 (define-syntax-rule (build-lexical-var src id)
462 (gensym (string-append (symbol->string id) "-")))
464 (define-structure (syntax-object expression wrap module))
466 (define-syntax no-source (identifier-syntax #f))
468 (define source-annotation
470 (let ((props (source-properties
471 (if (syntax-object? x)
472 (syntax-object-expression x)
474 (and (pair? props) props))))
476 (define-syntax-rule (arg-check pred? e who)
478 (if (not (pred? x)) (syntax-violation who "invalid argument" x))))
480 ;; compile-time environments
482 ;; wrap and environment comprise two level mapping.
483 ;; wrap : id --> label
484 ;; env : label --> <element>
486 ;; environments are represented in two parts: a lexical part and a global
487 ;; part. The lexical part is a simple list of associations from labels
488 ;; to bindings. The global part is implemented by
489 ;; {put,get}-global-definition-hook and associates symbols with
492 ;; global (assumed global variable) and displaced-lexical (see below)
493 ;; do not show up in any environment; instead, they are fabricated by
494 ;; lookup when it finds no other bindings.
496 ;; <environment> ::= ((<label> . <binding>)*)
498 ;; identifier bindings include a type and a value
500 ;; <binding> ::= (macro . <procedure>) macros
501 ;; (core . <procedure>) core forms
502 ;; (module-ref . <procedure>) @ or @@
505 ;; (define-syntax) define-syntax
506 ;; (define-syntax-parameter) define-syntax-parameter
507 ;; (local-syntax . rec?) let-syntax/letrec-syntax
508 ;; (eval-when) eval-when
509 ;; (syntax . (<var> . <level>)) pattern variables
510 ;; (global) assumed global variable
511 ;; (lexical . <var>) lexical variables
512 ;; (displaced-lexical) displaced lexicals
513 ;; <level> ::= <nonnegative integer>
514 ;; <var> ::= variable returned by build-lexical-var
516 ;; a macro is a user-defined syntactic-form. a core is a
517 ;; system-defined syntactic form. begin, define, define-syntax,
518 ;; define-syntax-parameter, and eval-when are treated specially
519 ;; since they are sensitive to whether the form is at top-level and
520 ;; (except for eval-when) can denote valid internal definitions.
522 ;; a pattern variable is a variable introduced by syntax-case and can
523 ;; be referenced only within a syntax form.
525 ;; any identifier for which no top-level syntax definition or local
526 ;; binding of any kind has been seen is assumed to be a global
529 ;; a lexical variable is a lambda- or letrec-bound variable.
531 ;; a displaced-lexical identifier is a lexical identifier removed from
532 ;; it's scope by the return of a syntax object containing the identifier.
533 ;; a displaced lexical can also appear when a letrec-syntax-bound
534 ;; keyword is referenced on the rhs of one of the letrec-syntax clauses.
535 ;; a displaced lexical should never occur with properly written macros.
537 (define-syntax make-binding
538 (syntax-rules (quote)
539 ((_ type value) (cons type value))
541 ((_ type) (cons type '()))))
542 (define-syntax-rule (binding-type x)
544 (define-syntax-rule (binding-value x)
547 (define-syntax null-env (identifier-syntax '()))
550 (lambda (labels bindings r)
553 (extend-env (cdr labels) (cdr bindings)
554 (cons (cons (car labels) (car bindings)) r)))))
556 (define extend-var-env
557 ;; variant of extend-env that forms "lexical" binding
558 (lambda (labels vars r)
561 (extend-var-env (cdr labels) (cdr vars)
562 (cons (cons (car labels) (make-binding 'lexical (car vars))) r)))))
564 ;; we use a "macros only" environment in expansion of local macro
565 ;; definitions so that their definitions can use local macros without
566 ;; attempting to use other lexical identifiers.
567 (define macros-only-env
572 (if (eq? (cadr a) 'macro)
573 (cons a (macros-only-env (cdr r)))
574 (macros-only-env (cdr r)))))))
577 ;; x may be a label or a symbol
578 ;; although symbols are usually global, we check the environment first
579 ;; anyway because a temporary binding may have been established by
585 (or (get-global-definition-hook x mod) (make-binding 'global)))
586 (else (make-binding 'displaced-lexical)))))
588 (define global-extend
589 (lambda (type sym val)
590 (put-global-definition-hook sym type val)))
593 ;; Conceptually, identifiers are always syntax objects. Internally,
594 ;; however, the wrap is sometimes maintained separately (a source of
595 ;; efficiency and confusion), so that symbols are also considered
596 ;; identifiers by id?. Externally, they are always wrapped.
598 (define nonsymbol-id?
600 (and (syntax-object? x)
601 (symbol? (syntax-object-expression x)))))
607 ((syntax-object? x) (symbol? (syntax-object-expression x)))
610 (define-syntax-rule (id-sym-name e)
612 (if (syntax-object? x)
613 (syntax-object-expression x)
616 (define id-sym-name&marks
618 (if (syntax-object? x)
620 (syntax-object-expression x)
621 (join-marks (wrap-marks w) (wrap-marks (syntax-object-wrap x))))
622 (values x (wrap-marks w)))))
624 ;; syntax object wraps
626 ;; <wrap> ::= ((<mark> ...) . (<subst> ...))
627 ;; <subst> ::= shift | <subs>
628 ;; <subs> ::= #(ribcage #(<sym> ...) #(<mark> ...) #(<label> ...))
629 ;; | #(ribcage (<sym> ...) (<mark> ...) (<label> ...))
631 (define-syntax make-wrap (identifier-syntax cons))
632 (define-syntax wrap-marks (identifier-syntax car))
633 (define-syntax wrap-subst (identifier-syntax cdr))
635 ;; labels must be comparable with "eq?", have read-write invariance,
636 ;; and distinct from symbols.
638 (string-append "l-" (session-id) (symbol->string (gensym "-"))))
644 (cons (gen-label) (gen-labels (cdr ls))))))
646 (define-structure (ribcage symnames marks labels))
648 (define-syntax empty-wrap (identifier-syntax '(())))
650 (define-syntax top-wrap (identifier-syntax '((top))))
652 (define-syntax-rule (top-marked? w)
653 (memq 'top (wrap-marks w)))
655 ;; Marks must be comparable with "eq?" and distinct from pairs and
656 ;; the symbol top. We do not use integers so that marks will remain
657 ;; unique even across file compiles.
659 (define-syntax the-anti-mark (identifier-syntax #f))
663 (make-wrap (cons the-anti-mark (wrap-marks w))
664 (cons 'shift (wrap-subst w)))))
666 (define-syntax-rule (new-mark)
667 (gensym (string-append "m-" (session-id) "-")))
669 ;; make-empty-ribcage and extend-ribcage maintain list-based ribcages for
670 ;; internal definitions, in which the ribcages are built incrementally
671 (define-syntax-rule (make-empty-ribcage)
672 (make-ribcage '() '() '()))
674 (define extend-ribcage!
675 ;; must receive ids with complete wraps
676 (lambda (ribcage id label)
677 (set-ribcage-symnames! ribcage
678 (cons (syntax-object-expression id)
679 (ribcage-symnames ribcage)))
680 (set-ribcage-marks! ribcage
681 (cons (wrap-marks (syntax-object-wrap id))
682 (ribcage-marks ribcage)))
683 (set-ribcage-labels! ribcage
684 (cons label (ribcage-labels ribcage)))))
686 ;; make-binding-wrap creates vector-based ribcages
687 (define make-binding-wrap
688 (lambda (ids labels w)
694 (let ((labelvec (list->vector labels)))
695 (let ((n (vector-length labelvec)))
696 (let ((symnamevec (make-vector n)) (marksvec (make-vector n)))
697 (let f ((ids ids) (i 0))
698 (if (not (null? ids))
700 (lambda () (id-sym-name&marks (car ids) w))
701 (lambda (symname marks)
702 (vector-set! symnamevec i symname)
703 (vector-set! marksvec i marks)
704 (f (cdr ids) (fx+ i 1))))))
705 (make-ribcage symnamevec marksvec labelvec))))
716 (let ((m1 (wrap-marks w1)) (s1 (wrap-subst w1)))
722 (smart-append s1 (wrap-subst w2))))
724 (smart-append m1 (wrap-marks w2))
725 (smart-append s1 (wrap-subst w2)))))))
729 (smart-append m1 m2)))
736 (eq? (car x) (car y))
737 (same-marks? (cdr x) (cdr y))))))
741 (define-syntax-rule (first e)
742 ;; Rely on Guile's multiple-values truncation.
745 (lambda (sym subst marks)
748 (let ((fst (car subst)))
750 (search sym (cdr subst) (cdr marks))
751 (let ((symnames (ribcage-symnames fst)))
752 (if (vector? symnames)
753 (search-vector-rib sym subst marks symnames fst)
754 (search-list-rib sym subst marks symnames fst))))))))
755 (define search-list-rib
756 (lambda (sym subst marks symnames ribcage)
757 (let f ((symnames symnames) (i 0))
759 ((null? symnames) (search sym (cdr subst) marks))
760 ((and (eq? (car symnames) sym)
761 (same-marks? marks (list-ref (ribcage-marks ribcage) i)))
762 (values (list-ref (ribcage-labels ribcage) i) marks))
763 (else (f (cdr symnames) (fx+ i 1)))))))
764 (define search-vector-rib
765 (lambda (sym subst marks symnames ribcage)
766 (let ((n (vector-length symnames)))
769 ((fx= i n) (search sym (cdr subst) marks))
770 ((and (eq? (vector-ref symnames i) sym)
771 (same-marks? marks (vector-ref (ribcage-marks ribcage) i)))
772 (values (vector-ref (ribcage-labels ribcage) i) marks))
773 (else (f (fx+ i 1))))))))
776 (or (first (search id (wrap-subst w) (wrap-marks w))) id))
778 (let ((id (syntax-object-expression id))
779 (w1 (syntax-object-wrap id)))
780 (let ((marks (join-marks (wrap-marks w) (wrap-marks w1))))
781 (call-with-values (lambda () (search id (wrap-subst w) marks))
782 (lambda (new-id marks)
784 (first (search id (wrap-subst w1) marks))
786 (else (syntax-violation 'id-var-name "invalid id" id)))))
788 ;; A helper procedure for syntax-locally-bound-identifiers, which
789 ;; itself is a helper for transformer procedures.
790 ;; `locally-bound-identifiers' returns a list of all bindings
791 ;; visible to a syntax object with the given wrap. They are in
792 ;; order from outer to inner.
794 ;; The purpose of this procedure is to give a transformer procedure
795 ;; references on bound identifiers, that the transformer can then
796 ;; introduce some of them in its output. As such, the identifiers
797 ;; are anti-marked, so that rebuild-macro-output doesn't apply new
800 (define locally-bound-identifiers
803 (lambda (subst results)
806 (let ((fst (car subst)))
808 (scan (cdr subst) results)
809 (let ((symnames (ribcage-symnames fst))
810 (marks (ribcage-marks fst)))
811 (if (vector? symnames)
812 (scan-vector-rib subst symnames marks results)
813 (scan-list-rib subst symnames marks results))))))))
814 (define scan-list-rib
815 (lambda (subst symnames marks results)
816 (let f ((symnames symnames) (marks marks) (results results))
818 (scan (cdr subst) results)
819 (f (cdr symnames) (cdr marks)
820 (cons (wrap (car symnames)
821 (anti-mark (make-wrap (car marks) subst))
824 (define scan-vector-rib
825 (lambda (subst symnames marks results)
826 (let ((n (vector-length symnames)))
827 (let f ((i 0) (results results))
829 (scan (cdr subst) results)
831 (cons (wrap (vector-ref symnames i)
832 (anti-mark (make-wrap (vector-ref marks i) subst))
835 (scan (wrap-subst w) '())))
837 ;; Returns three values: binding type, binding value, the module (for
838 ;; resolving toplevel vars).
839 (define (resolve-identifier id w r mod)
840 (define (resolve-global var mod)
841 (let ((b (or (get-global-definition-hook var mod)
842 (make-binding 'global))))
843 (if (eq? (binding-type b) 'global)
844 (values 'global var mod)
845 (values (binding-type b) (binding-value b) mod))))
846 (define (resolve-lexical label mod)
847 (let ((b (or (assq-ref r label)
848 (make-binding 'displaced-lexical))))
849 (values (binding-type b) (binding-value b) mod)))
850 (let ((n (id-var-name id w)))
853 (resolve-global n (if (syntax-object? id)
854 (syntax-object-module id)
857 (resolve-lexical n (if (syntax-object? id)
858 (syntax-object-module id)
861 (error "unexpected id-var-name" id w n)))))
863 (define transformer-environment
866 (error "called outside the dynamic extent of a syntax transformer"))))
868 (define (with-transformer-environment k)
869 ((fluid-ref transformer-environment) k))
871 ;; free-id=? must be passed fully wrapped ids since (free-id=? x y)
872 ;; may be true even if (free-id=? (wrap x w) (wrap y w)) is not.
876 (and (eq? (id-sym-name i) (id-sym-name j)) ; accelerator
877 (eq? (id-var-name i empty-wrap) (id-var-name j empty-wrap)))))
879 ;; bound-id=? may be passed unwrapped (or partially wrapped) ids as
880 ;; long as the missing portion of the wrap is common to both of the ids
881 ;; since (bound-id=? x y) iff (bound-id=? (wrap x w) (wrap y w))
885 (if (and (syntax-object? i) (syntax-object? j))
886 (and (eq? (syntax-object-expression i)
887 (syntax-object-expression j))
888 (same-marks? (wrap-marks (syntax-object-wrap i))
889 (wrap-marks (syntax-object-wrap j))))
892 ;; "valid-bound-ids?" returns #t if it receives a list of distinct ids.
893 ;; valid-bound-ids? may be passed unwrapped (or partially wrapped) ids
894 ;; as long as the missing portion of the wrap is common to all of the
897 (define valid-bound-ids?
899 (and (let all-ids? ((ids ids))
902 (all-ids? (cdr ids)))))
903 (distinct-bound-ids? ids))))
905 ;; distinct-bound-ids? expects a list of ids and returns #t if there are
906 ;; no duplicates. It is quadratic on the length of the id list; long
907 ;; lists could be sorted to make it more efficient. distinct-bound-ids?
908 ;; may be passed unwrapped (or partially wrapped) ids as long as the
909 ;; missing portion of the wrap is common to all of the ids.
911 (define distinct-bound-ids?
913 (let distinct? ((ids ids))
915 (and (not (bound-id-member? (car ids) (cdr ids)))
916 (distinct? (cdr ids)))))))
918 (define bound-id-member?
920 (and (not (null? list))
921 (or (bound-id=? x (car list))
922 (bound-id-member? x (cdr list))))))
924 ;; wrapping expressions and identifiers
929 ((and (null? (wrap-marks w)) (null? (wrap-subst w))) x)
932 (syntax-object-expression x)
933 (join-wraps w (syntax-object-wrap x))
934 (syntax-object-module x)))
936 (else (make-syntax-object x w defmod)))))
939 (lambda (x w s defmod)
940 (wrap (decorate-source x s) w defmod)))
944 (define expand-sequence
945 (lambda (body r w s mod)
947 (let dobody ((body body) (r r) (w w) (mod mod))
950 (let ((first (expand (car body) r w mod)))
951 (cons first (dobody (cdr body) r w mod))))))))
953 ;; At top-level, we allow mixed definitions and expressions. Like
954 ;; expand-body we expand in two passes.
956 ;; First, from left to right, we expand just enough to know what
957 ;; expressions are definitions, syntax definitions, and splicing
958 ;; statements (`begin'). If we anything needs evaluating at
959 ;; expansion-time, it is expanded directly.
961 ;; Otherwise we collect expressions to expand, in thunks, and then
962 ;; expand them all at the end. This allows all syntax expanders
963 ;; visible in a toplevel sequence to be visible during the
964 ;; expansions of all normal definitions and expressions in the
967 (define expand-top-sequence
968 (lambda (body r w s m esew mod)
969 (define (scan body r w s m esew mod exps)
979 (let ((e (car body)))
980 (syntax-type e r w (or (source-annotation e) s) #f mod #f)))
981 (lambda (type value form e w s mod)
987 (scan #'(e1 e2 ...) r w s m esew mod exps))))
989 (expand-local-syntax value e r w s mod
990 (lambda (body r w s mod)
991 (scan body r w s m esew mod exps))))
994 ((_ (x ...) e1 e2 ...)
995 (let ((when-list (parse-when-list e #'(x ...)))
996 (body #'(e1 e2 ...)))
999 (if (memq 'eval when-list)
1001 (if (memq 'expand when-list) 'c&e 'e)
1005 (if (memq 'expand when-list)
1006 (top-level-eval-hook
1007 (expand-top-sequence body r w s 'e '(eval) mod)
1010 ((memq 'load when-list)
1011 (if (or (memq 'compile when-list)
1012 (memq 'expand when-list)
1013 (and (eq? m 'c&e) (memq 'eval when-list)))
1014 (scan body r w s 'c&e '(compile load) mod exps)
1015 (if (memq m '(c c&e))
1016 (scan body r w s 'c '(load) mod exps)
1018 ((or (memq 'compile when-list)
1019 (memq 'expand when-list)
1020 (and (eq? m 'c&e) (memq 'eval when-list)))
1021 (top-level-eval-hook
1022 (expand-top-sequence body r w s 'e '(eval) mod)
1027 ((define-syntax-form define-syntax-parameter-form)
1028 (let ((n (id-var-name value w)) (r (macros-only-env r)))
1031 (if (memq 'compile esew)
1032 (let ((e (expand-install-global n (expand e r w mod))))
1033 (top-level-eval-hook e mod)
1034 (if (memq 'load esew)
1035 (values (cons e exps))
1037 (if (memq 'load esew)
1038 (values (cons (expand-install-global n (expand e r w mod))
1042 (let ((e (expand-install-global n (expand e r w mod))))
1043 (top-level-eval-hook e mod)
1044 (values (cons e exps))))
1046 (if (memq 'eval esew)
1047 (top-level-eval-hook
1048 (expand-install-global n (expand e r w mod))
1052 (let* ((n (id-var-name value w))
1053 ;; Lookup the name in the module of the define form.
1054 (type (binding-type (lookup n r mod))))
1056 ((global core macro module-ref)
1057 ;; affect compile-time environment (once we have booted)
1058 (if (and (memq m '(c c&e))
1059 (not (module-local-variable (current-module) n))
1061 (let ((old (module-variable (current-module) n)))
1062 ;; use value of the same-named imported variable, if
1064 (if (and (variable? old) (variable-bound? old))
1065 (module-define! (current-module) n (variable-ref old))
1066 (module-add! (current-module) n (make-undefined-variable)))))
1070 (let ((x (build-global-definition s n (expand e r w mod))))
1071 (top-level-eval-hook x mod)
1074 (build-global-definition s n (expand e r w mod))))
1076 ((displaced-lexical)
1077 (syntax-violation #f "identifier out of context"
1078 (source-wrap form w s mod)
1079 (wrap value w mod)))
1081 (syntax-violation #f "cannot define keyword at top level"
1082 (source-wrap form w s mod)
1083 (wrap value w mod))))))
1087 (let ((x (expand-expr type value form e r w s mod)))
1088 (top-level-eval-hook x mod)
1091 (expand-expr type value form e r w s mod)))
1094 (scan (cdr body) r w s m esew mod exps))))))
1096 (call-with-values (lambda ()
1097 (scan body r w s m esew mod '()))
1103 (let lp ((in exps) (out '()))
1107 (cons (if (procedure? e) (e) e) out)))))))))))
1109 (define expand-install-global
1111 (build-global-definition
1116 (build-primref no-source 'make-syntax-transformer)
1117 (list (build-data no-source name)
1118 (build-data no-source 'macro)
1121 (define parse-when-list
1122 (lambda (e when-list)
1123 ;; when-list is syntax'd version of list of situations
1124 (let ((result (strip when-list empty-wrap)))
1125 (let lp ((l result))
1128 (if (memq (car l) '(compile load eval expand))
1130 (syntax-violation 'eval-when "invalid situation" e
1133 ;; syntax-type returns seven values: type, value, form, e, w, s, and
1134 ;; mod. The first two are described in the table below.
1136 ;; type value explanation
1137 ;; -------------------------------------------------------------------
1138 ;; core procedure core singleton
1139 ;; core-form procedure core form
1140 ;; module-ref procedure @ or @@ singleton
1141 ;; lexical name lexical variable reference
1142 ;; global name global variable reference
1143 ;; begin none begin keyword
1144 ;; define none define keyword
1145 ;; define-syntax none define-syntax keyword
1146 ;; define-syntax-parameter none define-syntax-parameter keyword
1147 ;; local-syntax rec? letrec-syntax/let-syntax keyword
1148 ;; eval-when none eval-when keyword
1149 ;; syntax level pattern variable
1150 ;; displaced-lexical none displaced lexical identifier
1151 ;; lexical-call name call to lexical variable
1152 ;; global-call name call to global variable
1153 ;; call none any other call
1154 ;; begin-form none begin expression
1155 ;; define-form id variable definition
1156 ;; define-syntax-form id syntax definition
1157 ;; define-syntax-parameter-form id syntax parameter definition
1158 ;; local-syntax-form rec? syntax definition
1159 ;; eval-when-form none eval-when form
1160 ;; constant none self-evaluating datum
1161 ;; other none anything else
1163 ;; form is the entire form. For definition forms (define-form,
1164 ;; define-syntax-form, and define-syntax-parameter-form), e is the
1165 ;; rhs expression. For all others, e is the entire form. w is the
1166 ;; wrap for both form and e. s is the source for the entire form.
1167 ;; mod is the module for both form and e.
1169 ;; syntax-type expands macros and unwraps as necessary to get to one
1170 ;; of the forms above. It also parses definition forms, although
1171 ;; perhaps this should be done by the consumer.
1174 (lambda (e r w s rib mod for-car?)
1177 (let* ((n (id-var-name e w))
1178 (b (lookup n r mod))
1179 (type (binding-type b)))
1181 ((lexical) (values type (binding-value b) e e w s mod))
1182 ((global) (values type n e e w s mod))
1185 (values type (binding-value b) e e w s mod)
1186 (syntax-type (expand-macro (binding-value b) e r w s rib mod)
1187 r empty-wrap s rib mod #f)))
1188 (else (values type (binding-value b) e e w s mod)))))
1190 (let ((first (car e)))
1192 (lambda () (syntax-type first r w s rib mod #t))
1193 (lambda (ftype fval fform fe fw fs fmod)
1196 (values 'lexical-call fval e e w s mod))
1198 ;; If we got here via an (@@ ...) expansion, we need to
1199 ;; make sure the fmod information is propagated back
1200 ;; correctly -- hence this consing.
1201 (values 'global-call (make-syntax-object fval w fmod)
1204 (syntax-type (expand-macro fval e r w s rib mod)
1205 r empty-wrap s rib mod for-car?))
1207 (call-with-values (lambda () (fval e r w))
1208 (lambda (e r w s mod)
1209 (syntax-type e r w s rib mod for-car?))))
1211 (values 'core-form fval e e w s mod))
1213 (values 'local-syntax-form fval e e w s mod))
1215 (values 'begin-form #f e e w s mod))
1217 (values 'eval-when-form #f e e w s mod))
1222 (values 'define-form #'name e #'val w s mod))
1223 ((_ (name . args) e1 e2 ...)
1225 (valid-bound-ids? (lambda-var-list #'args)))
1226 ;; need lambda here...
1227 (values 'define-form (wrap #'name w mod)
1230 (cons #'lambda (wrap #'(args e1 e2 ...) w mod))
1235 (values 'define-form (wrap #'name w mod)
1238 empty-wrap s mod))))
1243 (values 'define-syntax-form #'name e #'val w s mod))))
1244 ((define-syntax-parameter)
1248 (values 'define-syntax-parameter-form #'name e #'val w s mod))))
1250 (values 'call #f e e w s mod)))))))
1252 (syntax-type (syntax-object-expression e)
1254 (join-wraps w (syntax-object-wrap e))
1255 (or (source-annotation e) s) rib
1256 (or (syntax-object-module e) mod) for-car?))
1257 ((self-evaluating? e) (values 'constant #f e e w s mod))
1258 (else (values 'other #f e e w s mod)))))
1263 (lambda () (syntax-type e r w (source-annotation e) #f mod #f))
1264 (lambda (type value form e w s mod)
1265 (expand-expr type value form e r w s mod)))))
1268 (lambda (type value form e r w s mod)
1271 (build-lexical-reference 'value s e value))
1273 ;; apply transformer
1274 (value e r w s mod))
1276 (call-with-values (lambda () (value e r w))
1277 (lambda (e r w s mod)
1278 (expand e r w mod))))
1282 (build-lexical-reference 'fun (source-annotation id)
1283 (if (syntax-object? id)
1290 (build-global-reference (source-annotation (car e))
1291 (if (syntax-object? value)
1292 (syntax-object-expression value)
1294 (if (syntax-object? value)
1295 (syntax-object-module value)
1298 ((constant) (build-data s (strip (source-wrap e w s mod) empty-wrap)))
1299 ((global) (build-global-reference s value mod))
1300 ((call) (expand-application (expand (car e) r w mod) e r w s mod))
1303 ((_ e1 e2 ...) (expand-sequence #'(e1 e2 ...) r w s mod))
1305 (if (include-deprecated-features)
1307 (issue-deprecation-warning
1308 "Sequences of zero expressions are deprecated. Use *unspecified*.")
1310 (syntax-violation #f "sequence of zero expressions"
1311 (source-wrap e w s mod))))))
1312 ((local-syntax-form)
1313 (expand-local-syntax value e r w s mod expand-sequence))
1316 ((_ (x ...) e1 e2 ...)
1317 (let ((when-list (parse-when-list e #'(x ...))))
1318 (if (memq 'eval when-list)
1319 (expand-sequence #'(e1 e2 ...) r w s mod)
1321 ((define-form define-syntax-form define-syntax-parameter-form)
1322 (syntax-violation #f "definition in expression context, where definitions are not allowed,"
1323 (source-wrap form w s mod)))
1325 (syntax-violation #f "reference to pattern variable outside syntax form"
1326 (source-wrap e w s mod)))
1327 ((displaced-lexical)
1328 (syntax-violation #f "reference to identifier outside its scope"
1329 (source-wrap e w s mod)))
1330 (else (syntax-violation #f "unexpected syntax"
1331 (source-wrap e w s mod))))))
1333 (define expand-application
1334 (lambda (x e r w s mod)
1337 (build-application s x
1338 (map (lambda (e) (expand e r w mod)) #'(e1 ...)))))))
1340 ;; (What follows is my interpretation of what's going on here -- Andy)
1342 ;; A macro takes an expression, a tree, the leaves of which are identifiers
1343 ;; and datums. Identifiers are symbols along with a wrap and a module. For
1344 ;; efficiency, subtrees that share wraps and modules may be grouped as one
1347 ;; Going into the expansion, the expression is given an anti-mark, which
1348 ;; logically propagates to all leaves. Then, in the new expression returned
1349 ;; from the transfomer, if we see an expression with an anti-mark, we know it
1350 ;; pertains to the original expression; conversely, expressions without the
1351 ;; anti-mark are known to be introduced by the transformer.
1353 ;; OK, good until now. We know this algorithm does lexical scoping
1354 ;; appropriately because it's widely known in the literature, and psyntax is
1355 ;; widely used. But what about modules? Here we're on our own. What we do is
1356 ;; to mark the module of expressions produced by a macro as pertaining to the
1357 ;; module that was current when the macro was defined -- that is, free
1358 ;; identifiers introduced by a macro are scoped in the macro's module, not in
1359 ;; the expansion's module. Seems to work well.
1361 ;; The only wrinkle is when we want a macro to expand to code in another
1362 ;; module, as is the case for the r6rs `library' form -- the body expressions
1363 ;; should be scoped relative the new module, the one defined by the macro.
1364 ;; For that, use `(@@ mod-name body)'.
1366 ;; Part of the macro output will be from the site of the macro use and part
1367 ;; from the macro definition. We allow source information from the macro use
1368 ;; to pass through, but we annotate the parts coming from the macro with the
1369 ;; source location information corresponding to the macro use. It would be
1370 ;; really nice if we could also annotate introduced expressions with the
1371 ;; locations corresponding to the macro definition, but that is not yet
1373 (define expand-macro
1374 (lambda (p e r w s rib mod)
1375 (define rebuild-macro-output
1379 (cons (rebuild-macro-output (car x) m)
1380 (rebuild-macro-output (cdr x) m))
1383 (let ((w (syntax-object-wrap x)))
1384 (let ((ms (wrap-marks w)) (ss (wrap-subst w)))
1385 (if (and (pair? ms) (eq? (car ms) the-anti-mark))
1386 ;; output is from original text
1388 (syntax-object-expression x)
1389 (make-wrap (cdr ms) (if rib (cons rib (cdr ss)) (cdr ss)))
1390 (syntax-object-module x))
1391 ;; output introduced by macro
1393 (decorate-source (syntax-object-expression x) s)
1394 (make-wrap (cons m ms)
1396 (cons rib (cons 'shift ss))
1398 (syntax-object-module x))))))
1401 (let* ((n (vector-length x))
1402 (v (decorate-source (make-vector n) s)))
1403 (do ((i 0 (fx+ i 1)))
1406 (rebuild-macro-output (vector-ref x i) m)))))
1408 (syntax-violation #f "encountered raw symbol in macro output"
1409 (source-wrap e w (wrap-subst w) mod) x))
1410 (else (decorate-source x s)))))
1411 (with-fluids ((transformer-environment
1412 (lambda (k) (k e r w s rib mod))))
1413 (rebuild-macro-output (p (source-wrap e (anti-mark w) s mod))
1417 ;; In processing the forms of the body, we create a new, empty wrap.
1418 ;; This wrap is augmented (destructively) each time we discover that
1419 ;; the next form is a definition. This is done:
1421 ;; (1) to allow the first nondefinition form to be a call to
1422 ;; one of the defined ids even if the id previously denoted a
1423 ;; definition keyword or keyword for a macro expanding into a
1425 ;; (2) to prevent subsequent definition forms (but unfortunately
1426 ;; not earlier ones) and the first nondefinition form from
1427 ;; confusing one of the bound identifiers for an auxiliary
1429 ;; (3) so that we do not need to restart the expansion of the
1430 ;; first nondefinition form, which is problematic anyway
1431 ;; since it might be the first element of a begin that we
1432 ;; have just spliced into the body (meaning if we restarted,
1433 ;; we'd really need to restart with the begin or the macro
1434 ;; call that expanded into the begin, and we'd have to give
1435 ;; up allowing (begin <defn>+ <expr>+), which is itself
1436 ;; problematic since we don't know if a begin contains only
1437 ;; definitions until we've expanded it).
1439 ;; Before processing the body, we also create a new environment
1440 ;; containing a placeholder for the bindings we will add later and
1441 ;; associate this environment with each form. In processing a
1442 ;; let-syntax or letrec-syntax, the associated environment may be
1443 ;; augmented with local keyword bindings, so the environment may
1444 ;; be different for different forms in the body. Once we have
1445 ;; gathered up all of the definitions, we evaluate the transformer
1446 ;; expressions and splice into r at the placeholder the new variable
1447 ;; and keyword bindings. This allows let-syntax or letrec-syntax
1448 ;; forms local to a portion or all of the body to shadow the
1449 ;; definition bindings.
1451 ;; Subforms of a begin, let-syntax, or letrec-syntax are spliced
1454 ;; outer-form is fully wrapped w/source
1455 (lambda (body outer-form r w mod)
1456 (let* ((r (cons '("placeholder" . (placeholder)) r))
1457 (ribcage (make-empty-ribcage))
1458 (w (make-wrap (wrap-marks w) (cons ribcage (wrap-subst w)))))
1459 (let parse ((body (map (lambda (x) (cons r (wrap x w mod))) body))
1460 (ids '()) (labels '())
1461 (var-ids '()) (vars '()) (vals '()) (bindings '()))
1463 (syntax-violation #f "no expressions in body" outer-form)
1464 (let ((e (cdar body)) (er (caar body)))
1466 (lambda () (syntax-type e er empty-wrap (source-annotation e) ribcage mod #f))
1467 (lambda (type value form e w s mod)
1470 (let ((id (wrap value w mod)) (label (gen-label)))
1471 (let ((var (gen-var id)))
1472 (extend-ribcage! ribcage id label)
1474 (cons id ids) (cons label labels)
1476 (cons var vars) (cons (cons er (wrap e w mod)) vals)
1477 (cons (make-binding 'lexical var) bindings)))))
1478 ((define-syntax-form define-syntax-parameter-form)
1479 (let ((id (wrap value w mod))
1481 (trans-r (macros-only-env er)))
1482 (extend-ribcage! ribcage id label)
1483 ;; As required by R6RS, evaluate the right-hand-sides of internal
1484 ;; syntax definition forms and add their transformers to the
1485 ;; compile-time environment immediately, so that the newly-defined
1486 ;; keywords may be used in definition context within the same
1488 (set-cdr! r (extend-env (list label)
1489 (list (make-binding 'macro
1490 (eval-local-transformer
1491 (expand e trans-r w mod)
1494 (parse (cdr body) (cons id ids) labels var-ids vars vals bindings)))
1498 (parse (let f ((forms #'(e1 ...)))
1501 (cons (cons er (wrap (car forms) w mod))
1503 ids labels var-ids vars vals bindings))))
1504 ((local-syntax-form)
1505 (expand-local-syntax value e er w s mod
1506 (lambda (forms er w s mod)
1507 (parse (let f ((forms forms))
1510 (cons (cons er (wrap (car forms) w mod))
1512 ids labels var-ids vars vals bindings))))
1513 (else ; found a non-definition
1515 (build-sequence no-source
1517 (expand (cdr x) (car x) empty-wrap mod))
1518 (cons (cons er (source-wrap e w s mod))
1521 (if (not (valid-bound-ids? ids))
1523 #f "invalid or duplicate identifier in definition"
1525 (set-cdr! r (extend-env labels bindings (cdr r)))
1526 (build-letrec no-source #t
1527 (reverse (map syntax->datum var-ids))
1530 (expand (cdr x) (car x) empty-wrap mod))
1532 (build-sequence no-source
1534 (expand (cdr x) (car x) empty-wrap mod))
1535 (cons (cons er (source-wrap e w s mod))
1536 (cdr body)))))))))))))))))
1538 (define expand-local-syntax
1539 (lambda (rec? e r w s mod k)
1541 ((_ ((id val) ...) e1 e2 ...)
1542 (let ((ids #'(id ...)))
1543 (if (not (valid-bound-ids? ids))
1544 (syntax-violation #f "duplicate bound keyword" e)
1545 (let ((labels (gen-labels ids)))
1546 (let ((new-w (make-binding-wrap ids labels w)))
1550 (let ((w (if rec? new-w w))
1551 (trans-r (macros-only-env r)))
1553 (make-binding 'macro
1554 (eval-local-transformer
1555 (expand x trans-r w mod)
1562 (_ (syntax-violation #f "bad local syntax definition"
1563 (source-wrap e w s mod))))))
1565 (define eval-local-transformer
1566 (lambda (expanded mod)
1567 (let ((p (local-eval-hook expanded mod)))
1570 (syntax-violation #f "nonprocedure transformer" p)))))
1574 (build-void no-source)))
1578 (and (nonsymbol-id? x)
1579 (free-id=? x #'(... ...)))))
1581 (define lambda-formals
1583 (define (req args rreq)
1584 (syntax-case args ()
1586 (check (reverse rreq) #f))
1588 (req #'b (cons #'a rreq)))
1590 (check (reverse rreq) #'r))
1592 (syntax-violation 'lambda "invalid argument list" orig-args args))))
1593 (define (check req rest)
1595 ((distinct-bound-ids? (if rest (cons rest req) req))
1596 (values req #f rest #f))
1598 (syntax-violation 'lambda "duplicate identifier in argument list"
1600 (req orig-args '())))
1602 (define expand-simple-lambda
1603 (lambda (e r w s mod req rest meta body)
1604 (let* ((ids (if rest (append req (list rest)) req))
1605 (vars (map gen-var ids))
1606 (labels (gen-labels ids)))
1607 (build-simple-lambda
1609 (map syntax->datum req) (and rest (syntax->datum rest)) vars
1611 (expand-body body (source-wrap e w s mod)
1612 (extend-var-env labels vars r)
1613 (make-binding-wrap ids labels w)
1616 (define lambda*-formals
1618 (define (req args rreq)
1619 (syntax-case args ()
1621 (check (reverse rreq) '() #f '()))
1623 (req #'b (cons #'a rreq)))
1624 ((a . b) (eq? (syntax->datum #'a) #:optional)
1625 (opt #'b (reverse rreq) '()))
1626 ((a . b) (eq? (syntax->datum #'a) #:key)
1627 (key #'b (reverse rreq) '() '()))
1628 ((a b) (eq? (syntax->datum #'a) #:rest)
1629 (rest #'b (reverse rreq) '() '()))
1631 (rest #'r (reverse rreq) '() '()))
1633 (syntax-violation 'lambda* "invalid argument list" orig-args args))))
1634 (define (opt args req ropt)
1635 (syntax-case args ()
1637 (check req (reverse ropt) #f '()))
1639 (opt #'b req (cons #'(a #f) ropt)))
1640 (((a init) . b) (id? #'a)
1641 (opt #'b req (cons #'(a init) ropt)))
1642 ((a . b) (eq? (syntax->datum #'a) #:key)
1643 (key #'b req (reverse ropt) '()))
1644 ((a b) (eq? (syntax->datum #'a) #:rest)
1645 (rest #'b req (reverse ropt) '()))
1647 (rest #'r req (reverse ropt) '()))
1649 (syntax-violation 'lambda* "invalid optional argument list"
1651 (define (key args req opt rkey)
1652 (syntax-case args ()
1654 (check req opt #f (cons #f (reverse rkey))))
1656 (with-syntax ((k (symbol->keyword (syntax->datum #'a))))
1657 (key #'b req opt (cons #'(k a #f) rkey))))
1658 (((a init) . b) (id? #'a)
1659 (with-syntax ((k (symbol->keyword (syntax->datum #'a))))
1660 (key #'b req opt (cons #'(k a init) rkey))))
1661 (((a init k) . b) (and (id? #'a)
1662 (keyword? (syntax->datum #'k)))
1663 (key #'b req opt (cons #'(k a init) rkey)))
1664 ((aok) (eq? (syntax->datum #'aok) #:allow-other-keys)
1665 (check req opt #f (cons #t (reverse rkey))))
1666 ((aok a b) (and (eq? (syntax->datum #'aok) #:allow-other-keys)
1667 (eq? (syntax->datum #'a) #:rest))
1668 (rest #'b req opt (cons #t (reverse rkey))))
1669 ((aok . r) (and (eq? (syntax->datum #'aok) #:allow-other-keys)
1671 (rest #'r req opt (cons #t (reverse rkey))))
1672 ((a b) (eq? (syntax->datum #'a) #:rest)
1673 (rest #'b req opt (cons #f (reverse rkey))))
1675 (rest #'r req opt (cons #f (reverse rkey))))
1677 (syntax-violation 'lambda* "invalid keyword argument list"
1679 (define (rest args req opt kw)
1680 (syntax-case args ()
1682 (check req opt #'r kw))
1684 (syntax-violation 'lambda* "invalid rest argument"
1686 (define (check req opt rest kw)
1688 ((distinct-bound-ids?
1689 (append req (map car opt) (if rest (list rest) '())
1690 (if (pair? kw) (map cadr (cdr kw)) '())))
1691 (values req opt rest kw))
1693 (syntax-violation 'lambda* "duplicate identifier in argument list"
1695 (req orig-args '())))
1697 (define expand-lambda-case
1698 (lambda (e r w s mod get-formals clauses)
1699 (define (parse-req req opt rest kw body)
1700 (let ((vars (map gen-var req))
1701 (labels (gen-labels req)))
1702 (let ((r* (extend-var-env labels vars r))
1703 (w* (make-binding-wrap req labels w)))
1704 (parse-opt (map syntax->datum req)
1705 opt rest kw body (reverse vars) r* w* '() '()))))
1706 (define (parse-opt req opt rest kw body vars r* w* out inits)
1709 (syntax-case (car opt) ()
1711 (let* ((v (gen-var #'id))
1712 (l (gen-labels (list v)))
1713 (r** (extend-var-env l (list v) r*))
1714 (w** (make-binding-wrap (list #'id) l w*)))
1715 (parse-opt req (cdr opt) rest kw body (cons v vars)
1716 r** w** (cons (syntax->datum #'id) out)
1717 (cons (expand #'i r* w* mod) inits))))))
1719 (let* ((v (gen-var rest))
1720 (l (gen-labels (list v)))
1721 (r* (extend-var-env l (list v) r*))
1722 (w* (make-binding-wrap (list rest) l w*)))
1723 (parse-kw req (if (pair? out) (reverse out) #f)
1724 (syntax->datum rest)
1725 (if (pair? kw) (cdr kw) kw)
1726 body (cons v vars) r* w*
1727 (if (pair? kw) (car kw) #f)
1730 (parse-kw req (if (pair? out) (reverse out) #f) #f
1731 (if (pair? kw) (cdr kw) kw)
1733 (if (pair? kw) (car kw) #f)
1735 (define (parse-kw req opt rest kw body vars r* w* aok out inits)
1738 (syntax-case (car kw) ()
1740 (let* ((v (gen-var #'id))
1741 (l (gen-labels (list v)))
1742 (r** (extend-var-env l (list v) r*))
1743 (w** (make-binding-wrap (list #'id) l w*)))
1744 (parse-kw req opt rest (cdr kw) body (cons v vars)
1746 (cons (list (syntax->datum #'k)
1747 (syntax->datum #'id)
1750 (cons (expand #'i r* w* mod) inits))))))
1752 (parse-body req opt rest
1753 (if (or aok (pair? out)) (cons aok (reverse out)) #f)
1754 body (reverse vars) r* w* (reverse inits) '()))))
1755 (define (parse-body req opt rest kw body vars r* w* inits meta)
1756 (syntax-case body ()
1757 ((docstring e1 e2 ...) (string? (syntax->datum #'docstring))
1758 (parse-body req opt rest kw #'(e1 e2 ...) vars r* w* inits
1761 . ,(syntax->datum #'docstring))))))
1762 ((#((k . v) ...) e1 e2 ...)
1763 (parse-body req opt rest kw #'(e1 e2 ...) vars r* w* inits
1764 (append meta (syntax->datum #'((k . v) ...)))))
1766 (values meta req opt rest kw inits vars
1767 (expand-body #'(e1 e2 ...) (source-wrap e w s mod)
1770 (syntax-case clauses ()
1771 (() (values '() #f))
1772 (((args e1 e2 ...) (args* e1* e2* ...) ...)
1773 (call-with-values (lambda () (get-formals #'args))
1774 (lambda (req opt rest kw)
1775 (call-with-values (lambda ()
1776 (parse-req req opt rest kw #'(e1 e2 ...)))
1777 (lambda (meta req opt rest kw inits vars body)
1780 (expand-lambda-case e r w s mod get-formals
1781 #'((args* e1* e2* ...) ...)))
1782 (lambda (meta* else*)
1785 (build-lambda-case s req opt rest kw inits vars
1786 body else*))))))))))))
1790 ;; strips syntax-objects down to top-wrap
1792 ;; since only the head of a list is annotated by the reader, not each pair
1793 ;; in the spine, we also check for pairs whose cars are annotated in case
1794 ;; we've been passed the cdr of an annotated list
1803 (strip (syntax-object-expression x) (syntax-object-wrap x)))
1805 (let ((a (f (car x))) (d (f (cdr x))))
1806 (if (and (eq? a (car x)) (eq? d (cdr x)))
1810 (let ((old (vector->list x)))
1811 (let ((new (map f old)))
1812 ;; inlined and-map with two args
1813 (let lp ((l1 old) (l2 new))
1816 (if (eq? (car l1) (car l2))
1817 (lp (cdr l1) (cdr l2))
1818 (list->vector new)))))))
1821 ;; lexical variables
1825 (let ((id (if (syntax-object? id) (syntax-object-expression id) id)))
1826 (build-lexical-var no-source id))))
1828 ;; appears to return a reversed list
1829 (define lambda-var-list
1831 (let lvl ((vars vars) (ls '()) (w empty-wrap))
1833 ((pair? vars) (lvl (cdr vars) (cons (wrap (car vars) w #f) ls) w))
1834 ((id? vars) (cons (wrap vars w #f) ls))
1836 ((syntax-object? vars)
1837 (lvl (syntax-object-expression vars)
1839 (join-wraps w (syntax-object-wrap vars))))
1840 ;; include anything else to be caught by subsequent error
1842 (else (cons vars ls))))))
1844 ;; core transformers
1846 (global-extend 'local-syntax 'letrec-syntax #t)
1847 (global-extend 'local-syntax 'let-syntax #f)
1849 (global-extend 'core 'syntax-parameterize
1850 (lambda (e r w s mod)
1852 ((_ ((var val) ...) e1 e2 ...)
1853 (valid-bound-ids? #'(var ...))
1854 (let ((names (map (lambda (x) (id-var-name x w)) #'(var ...))))
1857 (case (binding-type (lookup n r mod))
1858 ((displaced-lexical)
1859 (syntax-violation 'syntax-parameterize
1860 "identifier out of context"
1862 (source-wrap id w s mod)))))
1867 (source-wrap e w s mod)
1870 (let ((trans-r (macros-only-env r)))
1872 (make-binding 'macro
1873 (eval-local-transformer (expand x trans-r w mod)
1879 (_ (syntax-violation 'syntax-parameterize "bad syntax"
1880 (source-wrap e w s mod))))))
1882 (global-extend 'core 'quote
1883 (lambda (e r w s mod)
1885 ((_ e) (build-data s (strip #'e w)))
1886 (_ (syntax-violation 'quote "bad syntax"
1887 (source-wrap e w s mod))))))
1889 (global-extend 'core 'syntax
1892 (lambda (src e r maps ellipsis? mod)
1894 (let ((label (id-var-name e empty-wrap)))
1895 ;; Mod does not matter, we are looking to see if
1896 ;; the id is lexical syntax.
1897 (let ((b (lookup label r mod)))
1898 (if (eq? (binding-type b) 'syntax)
1901 (let ((var.lev (binding-value b)))
1902 (gen-ref src (car var.lev) (cdr var.lev) maps)))
1903 (lambda (var maps) (values `(ref ,var) maps)))
1905 (syntax-violation 'syntax "misplaced ellipsis" src)
1906 (values `(quote ,e) maps)))))
1910 (gen-syntax src #'e r maps (lambda (x) #f) mod))
1912 ;; this could be about a dozen lines of code, except that we
1913 ;; choose to handle #'(x ... ...) forms
1919 (gen-syntax src #'x r
1920 (cons '() maps) ellipsis? mod))
1922 (if (null? (car maps))
1923 (syntax-violation 'syntax "extra ellipsis"
1925 (values (gen-map x (car maps))
1933 (lambda () (k (cons '() maps)))
1935 (if (null? (car maps))
1936 (syntax-violation 'syntax "extra ellipsis" src)
1937 (values (gen-mappend x (car maps))
1939 (_ (call-with-values
1940 (lambda () (gen-syntax src y r maps ellipsis? mod))
1943 (lambda () (k maps))
1945 (values (gen-append x y) maps)))))))))
1948 (lambda () (gen-syntax src #'x r maps ellipsis? mod))
1951 (lambda () (gen-syntax src #'y r maps ellipsis? mod))
1952 (lambda (y maps) (values (gen-cons x y) maps))))))
1956 (gen-syntax src #'(e1 e2 ...) r maps ellipsis? mod))
1957 (lambda (e maps) (values (gen-vector e) maps))))
1958 (_ (values `(quote ,e) maps))))))
1961 (lambda (src var level maps)
1965 (syntax-violation 'syntax "missing ellipsis" src)
1967 (lambda () (gen-ref src var (fx- level 1) (cdr maps)))
1968 (lambda (outer-var outer-maps)
1969 (let ((b (assq outer-var (car maps))))
1971 (values (cdr b) maps)
1972 (let ((inner-var (gen-var 'tmp)))
1974 (cons (cons (cons outer-var inner-var)
1976 outer-maps)))))))))))
1980 `(apply (primitive append) ,(gen-map e map-env))))
1984 (let ((formals (map cdr map-env))
1985 (actuals (map (lambda (x) `(ref ,(car x))) map-env)))
1988 ;; identity map equivalence:
1989 ;; (map (lambda (x) x) y) == y
1992 (lambda (x) (and (eq? (car x) 'ref) (memq (cadr x) formals)))
1994 ;; eta map equivalence:
1995 ;; (map (lambda (x ...) (f x ...)) y ...) == (map f y ...)
1996 `(map (primitive ,(car e))
1997 ,@(map (let ((r (map cons formals actuals)))
1998 (lambda (x) (cdr (assq (cadr x) r))))
2000 (else `(map (lambda ,formals ,e) ,@actuals))))))
2006 (if (eq? (car x) 'quote)
2007 `(quote (,(cadr x) . ,(cadr y)))
2008 (if (eq? (cadr y) '())
2011 ((list) `(list ,x ,@(cdr y)))
2012 (else `(cons ,x ,y)))))
2016 (if (equal? y '(quote ()))
2023 ((eq? (car x) 'list) `(vector ,@(cdr x)))
2024 ((eq? (car x) 'quote) `(quote #(,@(cadr x))))
2025 (else `(list->vector ,x)))))
2031 ((ref) (build-lexical-reference 'value no-source (cadr x) (cadr x)))
2032 ((primitive) (build-primref no-source (cadr x)))
2033 ((quote) (build-data no-source (cadr x)))
2035 (if (list? (cadr x))
2036 (build-simple-lambda no-source (cadr x) #f (cadr x) '() (regen (caddr x)))
2037 (error "how did we get here" x)))
2038 (else (build-application no-source
2039 (build-primref no-source (car x))
2040 (map regen (cdr x)))))))
2042 (lambda (e r w s mod)
2043 (let ((e (source-wrap e w s mod)))
2047 (lambda () (gen-syntax e #'x r '() ellipsis? mod))
2048 (lambda (e maps) (regen e))))
2049 (_ (syntax-violation 'syntax "bad `syntax' form" e)))))))
2051 (global-extend 'core 'lambda
2052 (lambda (e r w s mod)
2055 (call-with-values (lambda () (lambda-formals #'args))
2056 (lambda (req opt rest kw)
2057 (let lp ((body #'(e1 e2 ...)) (meta '()))
2058 (syntax-case body ()
2059 ((docstring e1 e2 ...) (string? (syntax->datum #'docstring))
2063 . ,(syntax->datum #'docstring))))))
2064 ((#((k . v) ...) e1 e2 ...)
2066 (append meta (syntax->datum #'((k . v) ...)))))
2067 (_ (expand-simple-lambda e r w s mod req rest meta body)))))))
2068 (_ (syntax-violation 'lambda "bad lambda" e)))))
2070 (global-extend 'core 'lambda*
2071 (lambda (e r w s mod)
2076 (expand-lambda-case e r w s mod
2077 lambda*-formals #'((args e1 e2 ...))))
2078 (lambda (meta lcase)
2079 (build-case-lambda s meta lcase))))
2080 (_ (syntax-violation 'lambda "bad lambda*" e)))))
2082 (global-extend 'core 'case-lambda
2083 (lambda (e r w s mod)
2084 (define (build-it meta clauses)
2087 (expand-lambda-case e r w s mod
2090 (lambda (meta* lcase)
2091 (build-case-lambda s (append meta meta*) lcase))))
2093 ((_ (args e1 e2 ...) ...)
2094 (build-it '() #'((args e1 e2 ...) ...)))
2095 ((_ docstring (args e1 e2 ...) ...)
2096 (string? (syntax->datum #'docstring))
2097 (build-it `((documentation
2098 . ,(syntax->datum #'docstring)))
2099 #'((args e1 e2 ...) ...)))
2100 (_ (syntax-violation 'case-lambda "bad case-lambda" e)))))
2102 (global-extend 'core 'case-lambda*
2103 (lambda (e r w s mod)
2104 (define (build-it meta clauses)
2107 (expand-lambda-case e r w s mod
2110 (lambda (meta* lcase)
2111 (build-case-lambda s (append meta meta*) lcase))))
2113 ((_ (args e1 e2 ...) ...)
2114 (build-it '() #'((args e1 e2 ...) ...)))
2115 ((_ docstring (args e1 e2 ...) ...)
2116 (string? (syntax->datum #'docstring))
2117 (build-it `((documentation
2118 . ,(syntax->datum #'docstring)))
2119 #'((args e1 e2 ...) ...)))
2120 (_ (syntax-violation 'case-lambda "bad case-lambda*" e)))))
2122 (global-extend 'core 'let
2124 (define (expand-let e r w s mod constructor ids vals exps)
2125 (if (not (valid-bound-ids? ids))
2126 (syntax-violation 'let "duplicate bound variable" e)
2127 (let ((labels (gen-labels ids))
2128 (new-vars (map gen-var ids)))
2129 (let ((nw (make-binding-wrap ids labels w))
2130 (nr (extend-var-env labels new-vars r)))
2132 (map syntax->datum ids)
2134 (map (lambda (x) (expand x r w mod)) vals)
2135 (expand-body exps (source-wrap e nw s mod)
2137 (lambda (e r w s mod)
2139 ((_ ((id val) ...) e1 e2 ...)
2140 (and-map id? #'(id ...))
2141 (expand-let e r w s mod
2146 ((_ f ((id val) ...) e1 e2 ...)
2147 (and (id? #'f) (and-map id? #'(id ...)))
2148 (expand-let e r w s mod
2153 (_ (syntax-violation 'let "bad let" (source-wrap e w s mod)))))))
2156 (global-extend 'core 'letrec
2157 (lambda (e r w s mod)
2159 ((_ ((id val) ...) e1 e2 ...)
2160 (and-map id? #'(id ...))
2161 (let ((ids #'(id ...)))
2162 (if (not (valid-bound-ids? ids))
2163 (syntax-violation 'letrec "duplicate bound variable" e)
2164 (let ((labels (gen-labels ids))
2165 (new-vars (map gen-var ids)))
2166 (let ((w (make-binding-wrap ids labels w))
2167 (r (extend-var-env labels new-vars r)))
2169 (map syntax->datum ids)
2171 (map (lambda (x) (expand x r w mod)) #'(val ...))
2172 (expand-body #'(e1 e2 ...)
2173 (source-wrap e w s mod) r w mod)))))))
2174 (_ (syntax-violation 'letrec "bad letrec" (source-wrap e w s mod))))))
2177 (global-extend 'core 'letrec*
2178 (lambda (e r w s mod)
2180 ((_ ((id val) ...) e1 e2 ...)
2181 (and-map id? #'(id ...))
2182 (let ((ids #'(id ...)))
2183 (if (not (valid-bound-ids? ids))
2184 (syntax-violation 'letrec* "duplicate bound variable" e)
2185 (let ((labels (gen-labels ids))
2186 (new-vars (map gen-var ids)))
2187 (let ((w (make-binding-wrap ids labels w))
2188 (r (extend-var-env labels new-vars r)))
2190 (map syntax->datum ids)
2192 (map (lambda (x) (expand x r w mod)) #'(val ...))
2193 (expand-body #'(e1 e2 ...)
2194 (source-wrap e w s mod) r w mod)))))))
2195 (_ (syntax-violation 'letrec* "bad letrec*" (source-wrap e w s mod))))))
2198 (global-extend 'core 'set!
2199 (lambda (e r w s mod)
2203 (let ((n (id-var-name #'id w))
2204 ;; Lookup id in its module
2205 (id-mod (if (syntax-object? #'id)
2206 (syntax-object-module #'id)
2208 (let ((b (lookup n r id-mod)))
2209 (case (binding-type b)
2211 (build-lexical-assignment s
2212 (syntax->datum #'id)
2214 (expand #'val r w mod)))
2216 (build-global-assignment s n (expand #'val r w mod) id-mod))
2218 (let ((p (binding-value b)))
2219 (if (procedure-property p 'variable-transformer)
2220 ;; As syntax-type does, call expand-macro with
2221 ;; the mod of the expression. Hmm.
2222 (expand (expand-macro p e r w s #f mod) r empty-wrap mod)
2223 (syntax-violation 'set! "not a variable transformer"
2225 (wrap #'id w id-mod)))))
2226 ((displaced-lexical)
2227 (syntax-violation 'set! "identifier out of context"
2229 (else (syntax-violation 'set! "bad set!"
2230 (source-wrap e w s mod)))))))
2231 ((_ (head tail ...) val)
2233 (lambda () (syntax-type #'head r empty-wrap no-source #f mod #t))
2234 (lambda (type value formform ee ww ss modmod)
2237 (let ((val (expand #'val r w mod)))
2238 (call-with-values (lambda () (value #'(head tail ...) r w))
2239 (lambda (e r w s* mod)
2242 (build-global-assignment s (syntax->datum #'e)
2245 (build-application s
2246 (expand #'(setter head) r w mod)
2247 (map (lambda (e) (expand e r w mod))
2248 #'(tail ... val))))))))
2249 (_ (syntax-violation 'set! "bad set!" (source-wrap e w s mod))))))
2251 (global-extend 'module-ref '@
2255 (and (and-map id? #'(mod ...)) (id? #'id))
2256 ;; Strip the wrap from the identifier and return top-wrap
2257 ;; so that the identifier will not be captured by lexicals.
2258 (values (syntax->datum #'id) r top-wrap #f
2260 #'(public mod ...)))))))
2262 (global-extend 'module-ref '@@
2267 (cons (remodulate (car x) mod)
2268 (remodulate (cdr x) mod)))
2271 (remodulate (syntax-object-expression x) mod)
2272 (syntax-object-wrap x)
2273 ;; hither the remodulation
2276 (let* ((n (vector-length x)) (v (make-vector n)))
2277 (do ((i 0 (fx+ i 1)))
2279 (vector-set! v i (remodulate (vector-ref x i) mod)))))
2283 (and (and-map id? #'(mod ...)) (id? #'id))
2284 ;; Strip the wrap from the identifier and return top-wrap
2285 ;; so that the identifier will not be captured by lexicals.
2286 (values (syntax->datum #'id) r top-wrap #f
2288 #'(private mod ...))))
2289 ((_ @@ (mod ...) exp)
2290 (and-map id? #'(mod ...))
2291 ;; This is a special syntax used to support R6RS library forms.
2292 ;; Unlike the syntax above, the last item is not restricted to
2293 ;; be a single identifier, and the syntax objects are kept
2294 ;; intact, with only their module changed.
2295 (let ((mod (syntax->datum #'(private mod ...))))
2296 (values (remodulate #'exp mod)
2297 r w (source-annotation #'exp)
2300 (global-extend 'core 'if
2301 (lambda (e r w s mod)
2306 (expand #'test r w mod)
2307 (expand #'then r w mod)
2308 (build-void no-source)))
2312 (expand #'test r w mod)
2313 (expand #'then r w mod)
2314 (expand #'else r w mod))))))
2316 (global-extend 'core 'with-fluids
2317 (lambda (e r w s mod)
2319 ((_ ((fluid val) ...) b b* ...)
2322 (map (lambda (x) (expand x r w mod)) #'(fluid ...))
2323 (map (lambda (x) (expand x r w mod)) #'(val ...))
2324 (expand-body #'(b b* ...)
2325 (source-wrap e w s mod) r w mod))))))
2327 (global-extend 'begin 'begin '())
2329 (global-extend 'define 'define '())
2331 (global-extend 'define-syntax 'define-syntax '())
2332 (global-extend 'define-syntax-parameter 'define-syntax-parameter '())
2334 (global-extend 'eval-when 'eval-when '())
2336 (global-extend 'core 'syntax-case
2338 (define convert-pattern
2339 ;; accepts pattern & keys
2340 ;; returns $sc-dispatch pattern & ids
2341 (lambda (pattern keys)
2347 (lambda () (cvt* #'y n ids))
2350 (lambda () (cvt #'x n ids))
2352 (values (cons x y) ids))))))
2353 (_ (cvt p* n ids)))))
2355 (define (v-reverse x)
2356 (let loop ((r '()) (x x))
2359 (loop (cons (car x) r) (cdr x)))))
2365 ((bound-id-member? p keys)
2366 (values (vector 'free-id p) ids))
2370 (values 'any (cons (cons p n) ids))))
2373 (ellipsis? (syntax dots))
2375 (lambda () (cvt (syntax x) (fx+ n 1) ids))
2377 (values (if (eq? p 'any) 'each-any (vector 'each p))
2380 (ellipsis? (syntax dots))
2382 (lambda () (cvt* (syntax ys) n ids))
2385 (lambda () (cvt (syntax x) (+ n 1) ids))
2388 (lambda () (v-reverse ys))
2390 (values `#(each+ ,x ,ys ,e)
2394 (lambda () (cvt (syntax y) n ids))
2397 (lambda () (cvt (syntax x) n ids))
2399 (values (cons x y) ids))))))
2400 (() (values '() ids))
2403 (lambda () (cvt (syntax (x ...)) n ids))
2404 (lambda (p ids) (values (vector 'vector p) ids))))
2405 (x (values (vector 'atom (strip p empty-wrap)) ids))))))
2406 (cvt pattern 0 '())))
2408 (define build-dispatch-call
2409 (lambda (pvars exp y r mod)
2410 (let ((ids (map car pvars)) (levels (map cdr pvars)))
2411 (let ((labels (gen-labels ids)) (new-vars (map gen-var ids)))
2412 (build-application no-source
2413 (build-primref no-source 'apply)
2414 (list (build-simple-lambda no-source (map syntax->datum ids) #f new-vars '()
2418 (map (lambda (var level)
2419 (make-binding 'syntax `(,var . ,level)))
2423 (make-binding-wrap ids labels empty-wrap)
2428 (lambda (x keys clauses r pat fender exp mod)
2430 (lambda () (convert-pattern pat keys))
2433 ((not (and-map (lambda (x) (not (ellipsis? (car x)))) pvars))
2434 (syntax-violation 'syntax-case "misplaced ellipsis" pat))
2435 ((not (distinct-bound-ids? (map car pvars)))
2436 (syntax-violation 'syntax-case "duplicate pattern variable" pat))
2438 (let ((y (gen-var 'tmp)))
2439 ;; fat finger binding and references to temp variable y
2440 (build-application no-source
2441 (build-simple-lambda no-source (list 'tmp) #f (list y) '()
2442 (let ((y (build-lexical-reference 'value no-source
2444 (build-conditional no-source
2445 (syntax-case fender ()
2447 (_ (build-conditional no-source
2449 (build-dispatch-call pvars fender y r mod)
2450 (build-data no-source #f))))
2451 (build-dispatch-call pvars exp y r mod)
2452 (gen-syntax-case x keys clauses r mod))))
2453 (list (if (eq? p 'any)
2454 (build-application no-source
2455 (build-primref no-source 'list)
2457 (build-application no-source
2458 (build-primref no-source '$sc-dispatch)
2459 (list x (build-data no-source p)))))))))))))
2461 (define gen-syntax-case
2462 (lambda (x keys clauses r mod)
2464 (build-application no-source
2465 (build-primref no-source 'syntax-violation)
2466 (list (build-data no-source #f)
2467 (build-data no-source
2468 "source expression failed to match any pattern")
2470 (syntax-case (car clauses) ()
2472 (if (and (id? #'pat)
2473 (and-map (lambda (x) (not (free-id=? #'pat x)))
2474 (cons #'(... ...) keys)))
2475 (if (free-id=? #'pat #'_)
2476 (expand #'exp r empty-wrap mod)
2477 (let ((labels (list (gen-label)))
2478 (var (gen-var #'pat)))
2479 (build-application no-source
2480 (build-simple-lambda
2481 no-source (list (syntax->datum #'pat)) #f (list var)
2485 (list (make-binding 'syntax `(,var . 0)))
2487 (make-binding-wrap #'(pat)
2491 (gen-clause x keys (cdr clauses) r
2492 #'pat #t #'exp mod)))
2494 (gen-clause x keys (cdr clauses) r
2495 #'pat #'fender #'exp mod))
2496 (_ (syntax-violation 'syntax-case "invalid clause"
2499 (lambda (e r w s mod)
2500 (let ((e (source-wrap e w s mod)))
2502 ((_ val (key ...) m ...)
2503 (if (and-map (lambda (x) (and (id? x) (not (ellipsis? x))))
2505 (let ((x (gen-var 'tmp)))
2506 ;; fat finger binding and references to temp variable x
2507 (build-application s
2508 (build-simple-lambda no-source (list 'tmp) #f (list x) '()
2509 (gen-syntax-case (build-lexical-reference 'value no-source
2511 #'(key ...) #'(m ...)
2514 (list (expand #'val r empty-wrap mod))))
2515 (syntax-violation 'syntax-case "invalid literals list" e))))))))
2517 ;; The portable macroexpand seeds expand-top's mode m with 'e (for
2518 ;; evaluating) and esew (which stands for "eval syntax expanders
2519 ;; when") with '(eval). In Chez Scheme, m is set to 'c instead of e
2520 ;; if we are compiling a file, and esew is set to
2521 ;; (eval-syntactic-expanders-when), which defaults to the list
2522 ;; '(compile load eval). This means that, by default, top-level
2523 ;; syntactic definitions are evaluated immediately after they are
2524 ;; expanded, and the expanded definitions are also residualized into
2525 ;; the object file if we are compiling a file.
2527 (lambda* (x #:optional (m 'e) (esew '(eval)))
2528 (expand-top-sequence (list x) null-env top-wrap #f m esew
2529 (cons 'hygiene (module-name (current-module))))))
2537 (make-syntax-object datum (syntax-object-wrap id)
2538 (syntax-object-module id))))
2541 ;; accepts any object, since syntax objects may consist partially
2542 ;; or entirely of unwrapped, nonsymbolic data
2544 (strip x empty-wrap)))
2547 (lambda (x) (source-annotation x)))
2549 (set! generate-temporaries
2551 (arg-check list? ls 'generate-temporaries)
2552 (let ((mod (cons 'hygiene (module-name (current-module)))))
2553 (map (lambda (x) (wrap (gensym "t-") top-wrap mod)) ls))))
2555 (set! free-identifier=?
2557 (arg-check nonsymbol-id? x 'free-identifier=?)
2558 (arg-check nonsymbol-id? y 'free-identifier=?)
2561 (set! bound-identifier=?
2563 (arg-check nonsymbol-id? x 'bound-identifier=?)
2564 (arg-check nonsymbol-id? y 'bound-identifier=?)
2567 (set! syntax-violation
2568 (lambda* (who message form #:optional subform)
2569 (arg-check (lambda (x) (or (not x) (string? x) (symbol? x)))
2570 who 'syntax-violation)
2571 (arg-check string? message 'syntax-violation)
2572 (throw 'syntax-error who message
2573 (or (source-annotation subform)
2574 (source-annotation form))
2575 (strip form empty-wrap)
2576 (and subform (strip subform empty-wrap)))))
2579 (define (syntax-module id)
2580 (arg-check nonsymbol-id? id 'syntax-module)
2581 (cdr (syntax-object-module id)))
2583 (define (syntax-local-binding id)
2584 (arg-check nonsymbol-id? id 'syntax-local-binding)
2585 (with-transformer-environment
2586 (lambda (e r w s rib mod)
2587 (define (strip-anti-mark w)
2588 (let ((ms (wrap-marks w)) (s (wrap-subst w)))
2589 (if (and (pair? ms) (eq? (car ms) the-anti-mark))
2590 ;; output is from original text
2591 (make-wrap (cdr ms) (if rib (cons rib (cdr s)) (cdr s)))
2592 ;; output introduced by macro
2593 (make-wrap ms (if rib (cons rib s) s)))))
2594 (call-with-values (lambda ()
2596 (syntax-object-expression id)
2597 (strip-anti-mark (syntax-object-wrap id))
2599 (syntax-object-module id)))
2600 (lambda (type value mod)
2602 ((lexical) (values 'lexical value))
2603 ((macro) (values 'macro value))
2604 ((syntax) (values 'pattern-variable value))
2605 ((displaced-lexical) (values 'displaced-lexical #f))
2606 ((global) (values 'global (cons value (cdr mod))))
2607 (else (values 'other #f))))))))
2609 (define (syntax-locally-bound-identifiers id)
2610 (arg-check nonsymbol-id? id 'syntax-locally-bound-identifiers)
2611 (locally-bound-identifiers (syntax-object-wrap id)
2612 (syntax-object-module id)))
2614 ;; Using define! instead of set! to avoid warnings at
2615 ;; compile-time, after the variables are stolen away into (system
2616 ;; syntax). See the end of boot-9.scm.
2618 (define! 'syntax-module syntax-module)
2619 (define! 'syntax-local-binding syntax-local-binding)
2620 (define! 'syntax-locally-bound-identifiers syntax-locally-bound-identifiers))
2622 ;; $sc-dispatch expects an expression and a pattern. If the expression
2623 ;; matches the pattern a list of the matching expressions for each
2624 ;; "any" is returned. Otherwise, #f is returned. (This use of #f will
2625 ;; not work on r4rs implementations that violate the ieee requirement
2626 ;; that #f and () be distinct.)
2628 ;; The expression is matched with the pattern as follows:
2630 ;; pattern: matches:
2633 ;; (<pattern>1 . <pattern>2) (<pattern>1 . <pattern>2)
2635 ;; #(free-id <key>) <key> with free-identifier=?
2636 ;; #(each <pattern>) (<pattern>*)
2637 ;; #(each+ p1 (p2_1 ... p2_n) p3) (p1* (p2_n ... p2_1) . p3)
2638 ;; #(vector <pattern>) (list->vector <pattern>)
2639 ;; #(atom <object>) <object> with "equal?"
2641 ;; Vector cops out to pair under assumption that vectors are rare. If
2642 ;; not, should convert to:
2643 ;; #(vector <pattern>*) #(<pattern>*)
2651 (let ((first (match (car e) p w '() mod)))
2653 (let ((rest (match-each (cdr e) p w mod)))
2654 (and rest (cons first rest))))))
2657 (match-each (syntax-object-expression e)
2659 (join-wraps w (syntax-object-wrap e))
2660 (syntax-object-module e)))
2664 (lambda (e x-pat y-pat z-pat w r mod)
2665 (let f ((e e) (w w))
2668 (call-with-values (lambda () (f (cdr e) w))
2669 (lambda (xr* y-pat r)
2672 (let ((xr (match (car e) x-pat w '() mod)))
2674 (values (cons xr xr*) y-pat r)
2679 (match (car e) (car y-pat) w r mod)))
2680 (values #f #f #f)))))
2682 (f (syntax-object-expression e) (join-wraps w e)))
2684 (values '() y-pat (match e z-pat w r mod)))))))
2686 (define match-each-any
2690 (let ((l (match-each-any (cdr e) w mod)))
2691 (and l (cons (wrap (car e) w mod) l))))
2694 (match-each-any (syntax-object-expression e)
2695 (join-wraps w (syntax-object-wrap e))
2704 ((eq? p 'any) (cons '() r))
2705 ((pair? p) (match-empty (car p) (match-empty (cdr p) r)))
2706 ((eq? p 'each-any) (cons '() r))
2708 (case (vector-ref p 0)
2709 ((each) (match-empty (vector-ref p 1) r))
2710 ((each+) (match-empty (vector-ref p 1)
2712 (reverse (vector-ref p 2))
2713 (match-empty (vector-ref p 3) r))))
2715 ((vector) (match-empty (vector-ref p 1) r)))))))
2719 (if (null? (car r*))
2721 (cons (map car r*) (combine (map cdr r*) r)))))
2724 (lambda (e p w r mod)
2726 ((null? p) (and (null? e) r))
2728 (and (pair? e) (match (car e) (car p) w
2729 (match (cdr e) (cdr p) w r mod)
2732 (let ((l (match-each-any e w mod))) (and l (cons l r))))
2734 (case (vector-ref p 0)
2737 (match-empty (vector-ref p 1) r)
2738 (let ((l (match-each e (vector-ref p 1) w mod)))
2740 (let collect ((l l))
2743 (cons (map car l) (collect (map cdr l)))))))))
2747 (match-each+ e (vector-ref p 1) (vector-ref p 2) (vector-ref p 3) w r mod))
2748 (lambda (xr* y-pat r)
2752 (match-empty (vector-ref p 1) r)
2753 (combine xr* r))))))
2754 ((free-id) (and (id? e) (free-id=? (wrap e w mod) (vector-ref p 1)) r))
2755 ((atom) (and (equal? (vector-ref p 1) (strip e w)) r))
2758 (match (vector->list e) (vector-ref p 1) w r mod))))))))
2761 (lambda (e p w r mod)
2765 ((eq? p 'any) (cons (wrap e w mod) r))
2768 (syntax-object-expression e)
2770 (join-wraps w (syntax-object-wrap e))
2772 (syntax-object-module e)))
2773 (else (match* e p w r mod)))))
2778 ((eq? p 'any) (list e))
2781 (match* (syntax-object-expression e)
2782 p (syntax-object-wrap e) '() (syntax-object-module e)))
2783 (else (match* e p empty-wrap '() #f))))))))
2786 (define-syntax with-syntax
2790 #'(let () e1 e2 ...))
2791 ((_ ((out in)) e1 e2 ...)
2792 #'(syntax-case in ()
2793 (out (let () e1 e2 ...))))
2794 ((_ ((out in) ...) e1 e2 ...)
2795 #'(syntax-case (list in ...) ()
2796 ((out ...) (let () e1 e2 ...)))))))
2798 (define-syntax syntax-rules
2801 ((_ (k ...) ((keyword . pattern) template) ...)
2803 ;; embed patterns as procedure metadata
2804 #((macro-type . syntax-rules)
2805 (patterns pattern ...))
2806 (syntax-case x (k ...)
2807 ((dummy . pattern) #'template)
2809 ((_ (k ...) docstring ((keyword . pattern) template) ...)
2810 (string? (syntax->datum #'docstring))
2812 ;; the same, but allow a docstring
2814 #((macro-type . syntax-rules)
2815 (patterns pattern ...))
2816 (syntax-case x (k ...)
2817 ((dummy . pattern) #'template)
2820 (define-syntax define-syntax-rule
2823 ((_ (name . pattern) template)
2824 #'(define-syntax name
2826 ((_ . pattern) template))))
2827 ((_ (name . pattern) docstring template)
2828 (string? (syntax->datum #'docstring))
2829 #'(define-syntax name
2832 ((_ . pattern) template)))))))
2837 ((let* ((x v) ...) e1 e2 ...)
2838 (and-map identifier? #'(x ...))
2839 (let f ((bindings #'((x v) ...)))
2840 (if (null? bindings)
2841 #'(let () e1 e2 ...)
2842 (with-syntax ((body (f (cdr bindings)))
2843 (binding (car bindings)))
2844 #'(let (binding) body))))))))
2846 (define-syntax quasiquote
2848 (define (quasi p lev)
2849 (syntax-case p (unquote quasiquote)
2853 (quasicons #'("quote" unquote) (quasi #'(p) (- lev 1)))))
2854 ((quasiquote p) (quasicons #'("quote" quasiquote) (quasi #'(p) (+ lev 1))))
2856 (syntax-case #'p (unquote unquote-splicing)
2859 (quasilist* #'(("value" p) ...) (quasi #'q lev))
2861 (quasicons #'("quote" unquote) (quasi #'(p ...) (- lev 1)))
2863 ((unquote-splicing p ...)
2865 (quasiappend #'(("value" p) ...) (quasi #'q lev))
2867 (quasicons #'("quote" unquote-splicing) (quasi #'(p ...) (- lev 1)))
2869 (_ (quasicons (quasi #'p lev) (quasi #'q lev)))))
2870 (#(x ...) (quasivector (vquasi #'(x ...) lev)))
2872 (define (vquasi p lev)
2875 (syntax-case #'p (unquote unquote-splicing)
2878 (quasilist* #'(("value" p) ...) (vquasi #'q lev))
2880 (quasicons #'("quote" unquote) (quasi #'(p ...) (- lev 1)))
2882 ((unquote-splicing p ...)
2884 (quasiappend #'(("value" p) ...) (vquasi #'q lev))
2887 #'("quote" unquote-splicing)
2888 (quasi #'(p ...) (- lev 1)))
2890 (_ (quasicons (quasi #'p lev) (vquasi #'q lev)))))
2891 (() #'("quote" ()))))
2892 (define (quasicons x y)
2893 (with-syntax ((x x) (y y))
2897 (("quote" dx) #'("quote" (dx . dy)))
2898 (_ (if (null? #'dy) #'("list" x) #'("list*" x y)))))
2899 (("list" . stuff) #'("list" x . stuff))
2900 (("list*" . stuff) #'("list*" x . stuff))
2901 (_ #'("list*" x y)))))
2902 (define (quasiappend x y)
2906 ((null? x) #'("quote" ()))
2907 ((null? (cdr x)) (car x))
2908 (else (with-syntax (((p ...) x)) #'("append" p ...)))))
2912 (else (with-syntax (((p ...) x) (y y)) #'("append" p ... y)))))))
2913 (define (quasilist* x y)
2917 (quasicons (car x) (f (cdr x))))))
2918 (define (quasivector x)
2920 (("quote" (x ...)) #'("quote" #(x ...)))
2922 (let f ((y x) (k (lambda (ls) #`("vector" #,@ls))))
2924 (("quote" (y ...)) (k #'(("quote" y) ...)))
2925 (("list" y ...) (k #'(y ...)))
2926 (("list*" y ... z) (f #'z (lambda (ls) (k (append #'(y ...) ls)))))
2927 (else #`("list->vector" #,x)))))))
2931 (("list" x ...) #`(list #,@(map emit #'(x ...))))
2932 ;; could emit list* for 3+ arguments if implementation supports
2935 (let f ((x* #'(x ...)))
2938 #`(cons #,(emit (car x*)) #,(f (cdr x*))))))
2939 (("append" x ...) #`(append #,@(map emit #'(x ...))))
2940 (("vector" x ...) #`(vector #,@(map emit #'(x ...))))
2941 (("list->vector" x) #`(list->vector #,(emit #'x)))
2945 ;; convert to intermediate language, combining introduced (but
2946 ;; not unquoted source) quote expressions where possible and
2947 ;; choosing optimal construction code otherwise, then emit
2948 ;; Scheme code corresponding to the intermediate language forms.
2949 ((_ e) (emit (quasi #'e 0)))))))
2951 (define-syntax include
2955 (let* ((p (open-input-file
2956 (cond ((absolute-file-name? fn)
2959 (in-vicinity dir fn))
2963 "relative file name only allowed when the include form is in a file"
2965 (enc (file-encoding p)))
2967 ;; Choose the input encoding deterministically.
2968 (set-port-encoding! p (or enc "UTF-8"))
2970 (let f ((x (read p))
2974 (close-input-port p)
2977 (cons (datum->syntax k x) result)))))))
2978 (let* ((src (syntax-source x))
2979 (file (and src (assq-ref src 'filename)))
2980 (dir (and (string? file) (dirname file))))
2983 (let ((fn (syntax->datum #'filename)))
2984 (with-syntax (((exp ...) (read-file fn dir #'filename)))
2985 #'(begin exp ...))))))))
2987 (define-syntax include-from-path
2991 (let ((fn (syntax->datum #'filename)))
2992 (with-syntax ((fn (datum->syntax
2994 (or (%search-load-path fn)
2995 (syntax-violation 'include-from-path
2996 "file not found in path"
2998 #'(include fn)))))))
3000 (define-syntax unquote
3002 (syntax-violation 'unquote
3003 "expression not valid outside of quasiquote"
3006 (define-syntax unquote-splicing
3008 (syntax-violation 'unquote-splicing
3009 "expression not valid outside of quasiquote"
3012 (define (make-variable-transformer proc)
3013 (if (procedure? proc)
3014 (let ((trans (lambda (x)
3015 #((macro-type . variable-transformer))
3017 (set-procedure-property! trans 'variable-transformer #t)
3019 (error "variable transformer not a procedure" proc)))
3021 (define-syntax identifier-syntax
3023 (syntax-case xx (set!)
3026 #((macro-type . identifier-syntax))
3032 #'(e x (... ...))))))
3033 ((_ (id exp1) ((set! var val) exp2))
3034 (and (identifier? #'id) (identifier? #'var))
3035 #'(make-variable-transformer
3037 #((macro-type . variable-transformer))
3038 (syntax-case x (set!)
3039 ((set! var val) #'exp2)
3040 ((id x (... ...)) #'(exp1 x (... ...)))
3041 (id (identifier? #'id) #'exp1))))))))
3043 (define-syntax define*
3046 ((_ (id . args) b0 b1 ...)
3047 #'(define id (lambda* args b0 b1 ...)))
3048 ((_ id val) (identifier? #'id)
3049 #'(define id val)))))