3 ;;;; Copyright (C) 2001, 2003, 2006, 2009, 2010, 2011,
4 ;;;; 2012 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 file defines the syntax-case expander, macroexpand, and a set
47 ;;; of associated syntactic forms and procedures. Of these, the
48 ;;; following are documented in The Scheme Programming Language,
49 ;;; Fourth Edition (R. Kent Dybvig, MIT Press, 2009), and in the
52 ;;; bound-identifier=?
55 ;;; syntax-parameterize
57 ;;; generate-temporaries
68 ;;; Additionally, the expander provides definitions for a number of core
69 ;;; Scheme syntactic bindings, such as `let', `lambda', and the like.
71 ;;; The remaining exports are listed below:
73 ;;; (macroexpand datum)
74 ;;; if datum represents a valid expression, macroexpand returns an
75 ;;; expanded version of datum in a core language that includes no
76 ;;; syntactic abstractions. The core language includes begin,
77 ;;; define, if, lambda, letrec, quote, and set!.
78 ;;; (eval-when situations expr ...)
79 ;;; conditionally evaluates expr ... at compile-time or run-time
80 ;;; depending upon situations (see the Chez Scheme System Manual,
81 ;;; Revision 3, for a complete description)
82 ;;; (syntax-violation who message form [subform])
83 ;;; used to report errors found during expansion
84 ;;; ($sc-dispatch e p)
85 ;;; used by expanded code to handle syntax-case matching
87 ;;; This file is shipped along with an expanded version of itself,
88 ;;; psyntax-pp.scm, which is loaded when psyntax.scm has not yet been
89 ;;; compiled. In this way, psyntax bootstraps off of an expanded
90 ;;; version of itself.
92 ;;; This implementation of the expander sometimes uses syntactic
93 ;;; abstractions when procedural abstractions would suffice. For
94 ;;; example, we define top-wrap and top-marked? as
96 ;;; (define-syntax top-wrap (identifier-syntax '((top))))
97 ;;; (define-syntax top-marked?
99 ;;; ((_ w) (memq 'top (wrap-marks w)))))
103 ;;; (define top-wrap '((top)))
104 ;;; (define top-marked?
105 ;;; (lambda (w) (memq 'top (wrap-marks w))))
107 ;;; On the other hand, we don't do this consistently; we define
108 ;;; make-wrap, wrap-marks, and wrap-subst simply as
110 ;;; (define make-wrap cons)
111 ;;; (define wrap-marks car)
112 ;;; (define wrap-subst cdr)
114 ;;; In Chez Scheme, the syntactic and procedural forms of these
115 ;;; abstractions are equivalent, since the optimizer consistently
116 ;;; integrates constants and small procedures. This will be true of
117 ;;; Guile as well, once we implement a proper inliner.
120 ;;; Implementation notes:
122 ;;; Objects with no standard print syntax, including objects containing
123 ;;; cycles and syntax object, are allowed in quoted data as long as they
124 ;;; are contained within a syntax form or produced by datum->syntax.
125 ;;; Such objects are never copied.
127 ;;; All identifiers that don't have macro definitions and are not bound
128 ;;; lexically are assumed to be global variables.
130 ;;; Top-level definitions of macro-introduced identifiers are allowed.
131 ;;; This may not be appropriate for implementations in which the
132 ;;; model is that bindings are created by definitions, as opposed to
133 ;;; one in which initial values are assigned by definitions.
135 ;;; Identifiers and syntax objects are implemented as vectors for
136 ;;; portability. As a result, it is possible to "forge" syntax objects.
138 ;;; The implementation of generate-temporaries assumes that it is
139 ;;; possible to generate globally unique symbols (gensyms).
141 ;;; The source location associated with incoming expressions is tracked
142 ;;; via the source-properties mechanism, a weak map from expression to
143 ;;; source information. At times the source is separated from the
144 ;;; expression; see the note below about "efficiency and confusion".
149 ;;; When changing syntax-object representations, it is necessary to support
150 ;;; both old and new syntax-object representations in id-var-name. It
151 ;;; should be sufficient to recognize old representations and treat
152 ;;; them as not lexically bound.
157 (set-current-module (resolve-module '(guile))))
160 (define-syntax define-expansion-constructors
164 (let lp ((n 0) (out '()))
165 (if (< n (vector-length %expanded-vtables))
167 (let* ((vtable (vector-ref %expanded-vtables n))
168 (stem (struct-ref vtable (+ vtable-offset-user 0)))
169 (fields (struct-ref vtable (+ vtable-offset-user 2)))
170 (sfields (map (lambda (f) (datum->syntax x f)) fields))
171 (ctor (datum->syntax x (symbol-append 'make- stem))))
172 (cons #`(define (#,ctor #,@sfields)
173 (make-struct (vector-ref %expanded-vtables #,n) 0
176 #`(begin #,@(reverse out))))))))
178 (define-syntax define-expansion-accessors
183 (let ((vtable (vector-ref %expanded-vtables n))
184 (stem (syntax->datum #'stem)))
185 (if (eq? (struct-ref vtable (+ vtable-offset-user 0)) stem)
187 (define (#,(datum->syntax x (symbol-append stem '?)) x)
189 (eq? (struct-vtable x)
190 (vector-ref %expanded-vtables #,n))))
193 (let ((get (datum->syntax x (symbol-append stem '- f)))
194 (set (datum->syntax x (symbol-append 'set- stem '- f '!)))
195 (idx (list-index (struct-ref vtable
196 (+ vtable-offset-user 2))
200 (struct-ref x #,idx))
202 (struct-set! x #,idx v)))))
203 (syntax->datum #'(field ...))))
206 (define-syntax define-structure
208 (define construct-name
209 (lambda (template-identifier . args)
217 (symbol->string (syntax->datum x))))
221 (and-map identifier? #'(name id1 ...))
223 ((constructor (construct-name #'name "make-" #'name))
224 (predicate (construct-name #'name #'name "?"))
226 (map (lambda (x) (construct-name x #'name "-" x))
230 (construct-name x "set-" #'name "-" x "!"))
233 (+ (length #'(id1 ...)) 1))
235 (let f ((i 1) (ids #'(id1 ...)))
238 (cons i (f (+ i 1) (cdr ids)))))))
242 (vector 'name id1 ... )))
246 (= (vector-length x) structure-length)
247 (eq? (vector-ref x 0) 'name))))
250 (vector-ref x index)))
254 (vector-set! x index update)))
258 (define-expansion-constructors)
259 (define-expansion-accessors lambda meta)
261 ;; hooks to nonportable run-time helpers
263 (define-syntax fx+ (identifier-syntax +))
264 (define-syntax fx- (identifier-syntax -))
265 (define-syntax fx= (identifier-syntax =))
266 (define-syntax fx< (identifier-syntax <))
268 (define top-level-eval-hook
272 (define local-eval-hook
276 ;; Capture syntax-session-id before we shove it off into a module.
278 (let ((v (module-variable (current-module) 'syntax-session-id)))
280 ((variable-ref v)))))
282 (define put-global-definition-hook
283 (lambda (symbol type val)
284 (module-define! (current-module)
286 (make-syntax-transformer symbol type val))))
288 (define get-global-definition-hook
289 (lambda (symbol module)
290 (if (and (not module) (current-module))
291 (warn "module system is booted, we should have a module" symbol))
292 (let ((v (module-variable (if module
293 (resolve-module (cdr module))
296 (and v (variable-bound? v)
297 (let ((val (variable-ref v)))
298 (and (macro? val) (macro-type val)
299 (cons (macro-type val)
300 (macro-binding val)))))))))
303 (define (decorate-source e s)
304 (if (and s (supports-source-properties? e))
305 (set-source-properties! e s))
308 (define (maybe-name-value! name val)
310 (let ((meta (lambda-meta val)))
311 (if (not (assq 'name meta))
312 (set-lambda-meta! val (acons 'name name meta))))))
314 ;; output constructors
320 (lambda (source fun-exp arg-exps)
321 (make-call source fun-exp arg-exps)))
323 (define build-conditional
324 (lambda (source test-exp then-exp else-exp)
325 (make-conditional source test-exp then-exp else-exp)))
328 (lambda (source fluids vals body)
329 (make-dynlet source fluids vals body)))
331 (define build-lexical-reference
332 (lambda (type source name var)
333 (make-lexical-ref source name var)))
335 (define build-lexical-assignment
336 (lambda (source name var exp)
337 (maybe-name-value! name exp)
338 (make-lexical-set source name var exp)))
340 (define (analyze-variable mod var modref-cont bare-cont)
343 (let ((kind (car mod))
346 ((public) (modref-cont mod var #t))
347 ((private) (if (not (equal? mod (module-name (current-module))))
348 (modref-cont mod var #f)
350 ((bare) (bare-cont var))
351 ((hygiene) (if (and (not (equal? mod (module-name (current-module))))
352 (module-variable (resolve-module mod) var))
353 (modref-cont mod var #f)
355 (else (syntax-violation #f "bad module kind" var mod))))))
357 (define build-global-reference
358 (lambda (source var mod)
361 (lambda (mod var public?)
362 (make-module-ref source mod var public?))
364 (make-toplevel-ref source var)))))
366 (define build-global-assignment
367 (lambda (source var exp mod)
368 (maybe-name-value! var exp)
371 (lambda (mod var public?)
372 (make-module-set source mod var public? exp))
374 (make-toplevel-set source var exp)))))
376 (define build-global-definition
377 (lambda (source var exp)
378 (maybe-name-value! var exp)
379 (make-toplevel-define source var exp)))
381 (define build-simple-lambda
382 (lambda (src req rest vars meta exp)
385 ;; hah, a case in which kwargs would be nice.
387 ;; src req opt rest kw inits vars body else
388 src req #f rest #f '() vars exp #f))))
390 (define build-case-lambda
391 (lambda (src meta body)
392 (make-lambda src meta body)))
394 (define build-lambda-case
396 ;; opt := (name ...) | #f
398 ;; kw := (allow-other-keys? (keyword name var) ...) | #f
401 ;; vars map to named arguments in the following order:
402 ;; required, optional (positional), rest, keyword.
403 ;; the body of a lambda: anything, already expanded
404 ;; else: lambda-case | #f
405 (lambda (src req opt rest kw inits vars body else-case)
406 (make-lambda-case src req opt rest kw inits vars body else-case)))
408 (define build-primcall
409 (lambda (src name args)
410 (make-primcall src name args)))
412 (define build-primref
414 (make-primitive-ref src name)))
416 (define (build-data src exp)
417 (make-const src exp))
419 (define build-sequence
421 (if (null? (cdr exps))
423 (make-seq src (car exps) (build-sequence #f (cdr exps))))))
426 (lambda (src ids vars val-exps body-exp)
427 (for-each maybe-name-value! ids val-exps)
430 (make-let src ids vars val-exps body-exp))))
432 (define build-named-let
433 (lambda (src ids vars val-exps body-exp)
438 (let ((proc (build-simple-lambda src ids #f vars '() body-exp)))
439 (maybe-name-value! f-name proc)
440 (for-each maybe-name-value! ids val-exps)
443 (list f-name) (list f) (list proc)
444 (build-call src (build-lexical-reference 'fun src f-name f)
448 (lambda (src in-order? ids vars val-exps body-exp)
452 (for-each maybe-name-value! ids val-exps)
453 (make-letrec src in-order? ids vars val-exps body-exp)))))
456 ;; FIXME: use a faster gensym
457 (define-syntax-rule (build-lexical-var src id)
458 (gensym (string-append (symbol->string id) "-")))
460 (define-structure (syntax-object expression wrap module))
462 (define-syntax no-source (identifier-syntax #f))
464 (define source-annotation
466 (let ((props (source-properties
467 (if (syntax-object? x)
468 (syntax-object-expression x)
470 (and (pair? props) props))))
472 (define-syntax-rule (arg-check pred? e who)
474 (if (not (pred? x)) (syntax-violation who "invalid argument" x))))
476 ;; compile-time environments
478 ;; wrap and environment comprise two level mapping.
479 ;; wrap : id --> label
480 ;; env : label --> <element>
482 ;; environments are represented in two parts: a lexical part and a global
483 ;; part. The lexical part is a simple list of associations from labels
484 ;; to bindings. The global part is implemented by
485 ;; {put,get}-global-definition-hook and associates symbols with
488 ;; global (assumed global variable) and displaced-lexical (see below)
489 ;; do not show up in any environment; instead, they are fabricated by
490 ;; resolve-identifier when it finds no other bindings.
492 ;; <environment> ::= ((<label> . <binding>)*)
494 ;; identifier bindings include a type and a value
496 ;; <binding> ::= (macro . <procedure>) macros
497 ;; (syntax-parameter . (<procedure>)) syntax parameters
498 ;; (core . <procedure>) core forms
499 ;; (module-ref . <procedure>) @ or @@
502 ;; (define-syntax) define-syntax
503 ;; (define-syntax-parameter) define-syntax-parameter
504 ;; (local-syntax . rec?) let-syntax/letrec-syntax
505 ;; (eval-when) eval-when
506 ;; (syntax . (<var> . <level>)) pattern variables
507 ;; (global) assumed global variable
508 ;; (lexical . <var>) lexical variables
509 ;; (displaced-lexical) displaced lexicals
510 ;; <level> ::= <nonnegative integer>
511 ;; <var> ::= variable returned by build-lexical-var
513 ;; a macro is a user-defined syntactic-form. a core is a
514 ;; system-defined syntactic form. begin, define, define-syntax,
515 ;; define-syntax-parameter, and eval-when are treated specially
516 ;; since they are sensitive to whether the form is at top-level and
517 ;; (except for eval-when) can denote valid internal definitions.
519 ;; a pattern variable is a variable introduced by syntax-case and can
520 ;; be referenced only within a syntax form.
522 ;; any identifier for which no top-level syntax definition or local
523 ;; binding of any kind has been seen is assumed to be a global
526 ;; a lexical variable is a lambda- or letrec-bound variable.
528 ;; a displaced-lexical identifier is a lexical identifier removed from
529 ;; it's scope by the return of a syntax object containing the identifier.
530 ;; a displaced lexical can also appear when a letrec-syntax-bound
531 ;; keyword is referenced on the rhs of one of the letrec-syntax clauses.
532 ;; a displaced lexical should never occur with properly written macros.
534 (define-syntax make-binding
535 (syntax-rules (quote)
536 ((_ type value) (cons type value))
538 ((_ type) (cons type '()))))
539 (define-syntax-rule (binding-type x)
541 (define-syntax-rule (binding-value x)
544 (define-syntax null-env (identifier-syntax '()))
547 (lambda (labels bindings r)
550 (extend-env (cdr labels) (cdr bindings)
551 (cons (cons (car labels) (car bindings)) r)))))
553 (define extend-var-env
554 ;; variant of extend-env that forms "lexical" binding
555 (lambda (labels vars r)
558 (extend-var-env (cdr labels) (cdr vars)
559 (cons (cons (car labels) (make-binding 'lexical (car vars))) r)))))
561 ;; we use a "macros only" environment in expansion of local macro
562 ;; definitions so that their definitions can use local macros without
563 ;; attempting to use other lexical identifiers.
564 (define macros-only-env
569 (if (memq (cadr a) '(macro syntax-parameter))
570 (cons a (macros-only-env (cdr r)))
571 (macros-only-env (cdr r)))))))
573 (define global-extend
574 (lambda (type sym val)
575 (put-global-definition-hook sym type val)))
578 ;; Conceptually, identifiers are always syntax objects. Internally,
579 ;; however, the wrap is sometimes maintained separately (a source of
580 ;; efficiency and confusion), so that symbols are also considered
581 ;; identifiers by id?. Externally, they are always wrapped.
583 (define nonsymbol-id?
585 (and (syntax-object? x)
586 (symbol? (syntax-object-expression x)))))
592 ((syntax-object? x) (symbol? (syntax-object-expression x)))
595 (define-syntax-rule (id-sym-name e)
597 (if (syntax-object? x)
598 (syntax-object-expression x)
601 (define id-sym-name&marks
603 (if (syntax-object? x)
605 (syntax-object-expression x)
606 (join-marks (wrap-marks w) (wrap-marks (syntax-object-wrap x))))
607 (values x (wrap-marks w)))))
609 ;; syntax object wraps
611 ;; <wrap> ::= ((<mark> ...) . (<subst> ...))
612 ;; <subst> ::= shift | <subs>
613 ;; <subs> ::= #(ribcage #(<sym> ...) #(<mark> ...) #(<label> ...))
614 ;; | #(ribcage (<sym> ...) (<mark> ...) (<label> ...))
616 (define-syntax make-wrap (identifier-syntax cons))
617 (define-syntax wrap-marks (identifier-syntax car))
618 (define-syntax wrap-subst (identifier-syntax cdr))
620 ;; labels must be comparable with "eq?", have read-write invariance,
621 ;; and distinct from symbols.
623 (string-append "l-" (session-id) (symbol->string (gensym "-"))))
629 (cons (gen-label) (gen-labels (cdr ls))))))
631 (define-structure (ribcage symnames marks labels))
633 (define-syntax empty-wrap (identifier-syntax '(())))
635 (define-syntax top-wrap (identifier-syntax '((top))))
637 (define-syntax-rule (top-marked? w)
638 (memq 'top (wrap-marks w)))
640 ;; Marks must be comparable with "eq?" and distinct from pairs and
641 ;; the symbol top. We do not use integers so that marks will remain
642 ;; unique even across file compiles.
644 (define-syntax the-anti-mark (identifier-syntax #f))
648 (make-wrap (cons the-anti-mark (wrap-marks w))
649 (cons 'shift (wrap-subst w)))))
651 (define-syntax-rule (new-mark)
652 (gensym (string-append "m-" (session-id) "-")))
654 ;; make-empty-ribcage and extend-ribcage maintain list-based ribcages for
655 ;; internal definitions, in which the ribcages are built incrementally
656 (define-syntax-rule (make-empty-ribcage)
657 (make-ribcage '() '() '()))
659 (define extend-ribcage!
660 ;; must receive ids with complete wraps
661 (lambda (ribcage id label)
662 (set-ribcage-symnames! ribcage
663 (cons (syntax-object-expression id)
664 (ribcage-symnames ribcage)))
665 (set-ribcage-marks! ribcage
666 (cons (wrap-marks (syntax-object-wrap id))
667 (ribcage-marks ribcage)))
668 (set-ribcage-labels! ribcage
669 (cons label (ribcage-labels ribcage)))))
671 ;; make-binding-wrap creates vector-based ribcages
672 (define make-binding-wrap
673 (lambda (ids labels w)
679 (let ((labelvec (list->vector labels)))
680 (let ((n (vector-length labelvec)))
681 (let ((symnamevec (make-vector n)) (marksvec (make-vector n)))
682 (let f ((ids ids) (i 0))
683 (if (not (null? ids))
685 (lambda () (id-sym-name&marks (car ids) w))
686 (lambda (symname marks)
687 (vector-set! symnamevec i symname)
688 (vector-set! marksvec i marks)
689 (f (cdr ids) (fx+ i 1))))))
690 (make-ribcage symnamevec marksvec labelvec))))
701 (let ((m1 (wrap-marks w1)) (s1 (wrap-subst w1)))
707 (smart-append s1 (wrap-subst w2))))
709 (smart-append m1 (wrap-marks w2))
710 (smart-append s1 (wrap-subst w2)))))))
714 (smart-append m1 m2)))
721 (eq? (car x) (car y))
722 (same-marks? (cdr x) (cdr y))))))
725 ;; Syntax objects use wraps to associate names with marked
726 ;; identifiers. This function returns the name corresponding to
727 ;; the given identifier and wrap, or the original identifier if no
728 ;; corresponding name was found.
730 ;; The name may be a string created by gen-label, indicating a
731 ;; lexical binding, or another syntax object, indicating a
732 ;; reference to a top-level definition created during a previous
735 ;; For lexical variables, finding a label simply amounts to
736 ;; looking for an entry with the same symbolic name and the same
737 ;; marks. Finding a toplevel definition is the same, except we
738 ;; also have to compare modules, hence the `mod' parameter.
739 ;; Instead of adding a separate entry in the ribcage for modules,
740 ;; which wouldn't be used for lexicals, we arrange for the entry
741 ;; for the name entry to be a pair with the module in its car, and
742 ;; the name itself in the cdr. So if the name that we find is a
743 ;; pair, we have to check modules.
745 ;; The identifer may be passed in wrapped or unwrapped. In any
746 ;; case, this routine returns either a symbol, a syntax object, or
750 (define-syntax-rule (first e)
751 ;; Rely on Guile's multiple-values truncation.
754 (lambda (sym subst marks mod)
757 (let ((fst (car subst)))
759 (search sym (cdr subst) (cdr marks) mod)
760 (let ((symnames (ribcage-symnames fst)))
761 (if (vector? symnames)
762 (search-vector-rib sym subst marks symnames fst mod)
763 (search-list-rib sym subst marks symnames fst mod))))))))
764 (define search-list-rib
765 (lambda (sym subst marks symnames ribcage mod)
766 (let f ((symnames symnames) (i 0))
768 ((null? symnames) (search sym (cdr subst) marks mod))
769 ((and (eq? (car symnames) sym)
770 (same-marks? marks (list-ref (ribcage-marks ribcage) i)))
771 (let ((n (list-ref (ribcage-labels ribcage) i)))
773 (if (equal? mod (car n))
774 (values (cdr n) marks)
775 (f (cdr symnames) (fx+ i 1)))
777 (else (f (cdr symnames) (fx+ i 1)))))))
778 (define search-vector-rib
779 (lambda (sym subst marks symnames ribcage mod)
780 (let ((n (vector-length symnames)))
783 ((fx= i n) (search sym (cdr subst) marks mod))
784 ((and (eq? (vector-ref symnames i) sym)
785 (same-marks? marks (vector-ref (ribcage-marks ribcage) i)))
786 (let ((n (vector-ref (ribcage-labels ribcage) i)))
788 (if (equal? mod (car n))
789 (values (cdr n) marks)
792 (else (f (fx+ i 1))))))))
795 (or (first (search id (wrap-subst w) (wrap-marks w) mod)) id))
797 (let ((id (syntax-object-expression id))
798 (w1 (syntax-object-wrap id))
799 (mod (syntax-object-module id)))
800 (let ((marks (join-marks (wrap-marks w) (wrap-marks w1))))
801 (call-with-values (lambda () (search id (wrap-subst w) marks mod))
802 (lambda (new-id marks)
804 (first (search id (wrap-subst w1) marks mod))
806 (else (syntax-violation 'id-var-name "invalid id" id)))))
808 ;; A helper procedure for syntax-locally-bound-identifiers, which
809 ;; itself is a helper for transformer procedures.
810 ;; `locally-bound-identifiers' returns a list of all bindings
811 ;; visible to a syntax object with the given wrap. They are in
812 ;; order from outer to inner.
814 ;; The purpose of this procedure is to give a transformer procedure
815 ;; references on bound identifiers, that the transformer can then
816 ;; introduce some of them in its output. As such, the identifiers
817 ;; are anti-marked, so that rebuild-macro-output doesn't apply new
820 (define locally-bound-identifiers
823 (lambda (subst results)
826 (let ((fst (car subst)))
828 (scan (cdr subst) results)
829 (let ((symnames (ribcage-symnames fst))
830 (marks (ribcage-marks fst)))
831 (if (vector? symnames)
832 (scan-vector-rib subst symnames marks results)
833 (scan-list-rib subst symnames marks results))))))))
834 (define scan-list-rib
835 (lambda (subst symnames marks results)
836 (let f ((symnames symnames) (marks marks) (results results))
838 (scan (cdr subst) results)
839 (f (cdr symnames) (cdr marks)
840 (cons (wrap (car symnames)
841 (anti-mark (make-wrap (car marks) subst))
844 (define scan-vector-rib
845 (lambda (subst symnames marks results)
846 (let ((n (vector-length symnames)))
847 (let f ((i 0) (results results))
849 (scan (cdr subst) results)
851 (cons (wrap (vector-ref symnames i)
852 (anti-mark (make-wrap (vector-ref marks i) subst))
855 (scan (wrap-subst w) '())))
857 ;; Returns three values: binding type, binding value, the module (for
858 ;; resolving toplevel vars).
859 (define (resolve-identifier id w r mod resolve-syntax-parameters?)
860 (define (resolve-syntax-parameters b)
861 (if (and resolve-syntax-parameters?
862 (eq? (binding-type b) 'syntax-parameter))
863 (or (assq-ref r (binding-value b))
864 (make-binding 'macro (car (binding-value b))))
866 (define (resolve-global var mod)
867 (let ((b (resolve-syntax-parameters
868 (or (get-global-definition-hook var mod)
869 (make-binding 'global)))))
870 (if (eq? (binding-type b) 'global)
871 (values 'global var mod)
872 (values (binding-type b) (binding-value b) mod))))
873 (define (resolve-lexical label mod)
874 (let ((b (resolve-syntax-parameters
875 (or (assq-ref r label)
876 (make-binding 'displaced-lexical)))))
877 (values (binding-type b) (binding-value b) mod)))
878 (let ((n (id-var-name id w mod)))
881 ;; Recursing allows syntax-parameterize to override
882 ;; macro-introduced syntax parameters.
883 (resolve-identifier n w r mod resolve-syntax-parameters?))
885 (resolve-global n (if (syntax-object? id)
886 (syntax-object-module id)
889 (resolve-lexical n (if (syntax-object? id)
890 (syntax-object-module id)
893 (error "unexpected id-var-name" id w n)))))
895 (define transformer-environment
898 (error "called outside the dynamic extent of a syntax transformer"))))
900 (define (with-transformer-environment k)
901 ((fluid-ref transformer-environment) k))
903 ;; free-id=? must be passed fully wrapped ids since (free-id=? x y)
904 ;; may be true even if (free-id=? (wrap x w) (wrap y w)) is not.
908 (let* ((mi (and (syntax-object? i) (syntax-object-module i)))
909 (mj (and (syntax-object? j) (syntax-object-module j)))
910 (ni (id-var-name i empty-wrap mi))
911 (nj (id-var-name j empty-wrap mj)))
912 (define (id-module-binding id mod)
916 (resolve-module (cdr mod))
917 ;; Either modules have not been booted, or we have a
918 ;; raw symbol coming in, which is possible.
922 ((syntax-object? ni) (free-id=? ni j))
923 ((syntax-object? nj) (free-id=? i nj))
925 ;; `i' is not lexically bound. Assert that `j' is free,
926 ;; and if so, compare their bindings, that they are either
927 ;; bound to the same variable, or both unbound and have
929 (and (eq? nj (id-sym-name j))
930 (let ((bi (id-module-binding i mi)))
932 (eq? bi (id-module-binding j mj))
933 (and (not (id-module-binding j mj))
935 (eq? (id-module-binding i mi) (id-module-binding j mj))))
937 ;; Otherwise `i' is bound, so check that `j' is bound, and
938 ;; bound to the same thing.
941 ;; bound-id=? may be passed unwrapped (or partially wrapped) ids as
942 ;; long as the missing portion of the wrap is common to both of the ids
943 ;; since (bound-id=? x y) iff (bound-id=? (wrap x w) (wrap y w))
947 (if (and (syntax-object? i) (syntax-object? j))
948 (and (eq? (syntax-object-expression i)
949 (syntax-object-expression j))
950 (same-marks? (wrap-marks (syntax-object-wrap i))
951 (wrap-marks (syntax-object-wrap j))))
954 ;; "valid-bound-ids?" returns #t if it receives a list of distinct ids.
955 ;; valid-bound-ids? may be passed unwrapped (or partially wrapped) ids
956 ;; as long as the missing portion of the wrap is common to all of the
959 (define valid-bound-ids?
961 (and (let all-ids? ((ids ids))
964 (all-ids? (cdr ids)))))
965 (distinct-bound-ids? ids))))
967 ;; distinct-bound-ids? expects a list of ids and returns #t if there are
968 ;; no duplicates. It is quadratic on the length of the id list; long
969 ;; lists could be sorted to make it more efficient. distinct-bound-ids?
970 ;; may be passed unwrapped (or partially wrapped) ids as long as the
971 ;; missing portion of the wrap is common to all of the ids.
973 (define distinct-bound-ids?
975 (let distinct? ((ids ids))
977 (and (not (bound-id-member? (car ids) (cdr ids)))
978 (distinct? (cdr ids)))))))
980 (define bound-id-member?
982 (and (not (null? list))
983 (or (bound-id=? x (car list))
984 (bound-id-member? x (cdr list))))))
986 ;; wrapping expressions and identifiers
991 ((and (null? (wrap-marks w)) (null? (wrap-subst w))) x)
994 (syntax-object-expression x)
995 (join-wraps w (syntax-object-wrap x))
996 (syntax-object-module x)))
998 (else (make-syntax-object x w defmod)))))
1001 (lambda (x w s defmod)
1002 (wrap (decorate-source x s) w defmod)))
1006 (define expand-sequence
1007 (lambda (body r w s mod)
1009 (let dobody ((body body) (r r) (w w) (mod mod))
1012 (let ((first (expand (car body) r w mod)))
1013 (cons first (dobody (cdr body) r w mod))))))))
1015 ;; At top-level, we allow mixed definitions and expressions. Like
1016 ;; expand-body we expand in two passes.
1018 ;; First, from left to right, we expand just enough to know what
1019 ;; expressions are definitions, syntax definitions, and splicing
1020 ;; statements (`begin'). If we anything needs evaluating at
1021 ;; expansion-time, it is expanded directly.
1023 ;; Otherwise we collect expressions to expand, in thunks, and then
1024 ;; expand them all at the end. This allows all syntax expanders
1025 ;; visible in a toplevel sequence to be visible during the
1026 ;; expansions of all normal definitions and expressions in the
1029 (define expand-top-sequence
1030 (lambda (body r w s m esew mod)
1031 (let* ((r (cons '("placeholder" . (placeholder)) r))
1032 (ribcage (make-empty-ribcage))
1033 (w (make-wrap (wrap-marks w) (cons ribcage (wrap-subst w)))))
1034 (define (record-definition! id var)
1035 (let ((mod (cons 'hygiene (module-name (current-module)))))
1036 ;; Ribcages map symbol+marks to names, mostly for
1037 ;; resolving lexicals. Here to add a mapping for toplevel
1038 ;; definitions we also need to match the module. So, we
1039 ;; put it in the name instead, and make id-var-name handle
1040 ;; the special case of names that are pairs. See the
1041 ;; comments in id-var-name for more.
1042 (extend-ribcage! ribcage id
1043 (cons (syntax-object-module id)
1044 (wrap var top-wrap mod)))))
1045 (define (macro-introduced-identifier? id)
1046 (not (equal? (wrap-marks (syntax-object-wrap id)) '(top))))
1047 (define (fresh-derived-name id orig-form)
1049 (syntax-object-expression id)
1052 ;; FIXME: `hash' currently stops descending into nested
1053 ;; data at some point, so it's less unique than we would
1054 ;; like. Also this encodes hash values into the ABI of
1055 ;; compiled modules; a problem?
1057 (hash (syntax->datum orig-form) most-positive-fixnum)
1059 (define (parse body r w s m esew mod)
1060 (let lp ((body body) (exps '()))
1064 (append (parse1 (car body) r w s m esew mod)
1066 (define (parse1 x r w s m esew mod)
1069 (syntax-type x r w (source-annotation x) ribcage mod #f))
1070 (lambda (type value form e w s mod)
1073 (let* ((id (wrap value w mod))
1075 (var (if (macro-introduced-identifier? id)
1076 (fresh-derived-name id x)
1077 (syntax-object-expression id))))
1078 (record-definition! id var)
1081 (let ((x (build-global-definition s var (expand e r w mod))))
1082 (top-level-eval-hook x mod)
1085 (build-global-definition s var (expand e r w mod)))))))
1086 ((define-syntax-form define-syntax-parameter-form)
1087 (let* ((id (wrap value w mod))
1089 (var (if (macro-introduced-identifier? id)
1090 (fresh-derived-name id x)
1091 (syntax-object-expression id))))
1092 (record-definition! id var)
1096 ((memq 'compile esew)
1097 (let ((e (expand-install-global var type (expand e r w mod))))
1098 (top-level-eval-hook e mod)
1099 (if (memq 'load esew)
1100 (list (lambda () e))
1104 (expand-install-global var type (expand e r w mod)))))
1107 (let ((e (expand-install-global var type (expand e r w mod))))
1108 (top-level-eval-hook e mod)
1109 (list (lambda () e))))
1111 (if (memq 'eval esew)
1112 (top-level-eval-hook
1113 (expand-install-global var type (expand e r w mod))
1119 (parse #'(e1 ...) r w s m esew mod))))
1120 ((local-syntax-form)
1121 (expand-local-syntax value e r w s mod
1122 (lambda (forms r w s mod)
1123 (parse forms r w s m esew mod))))
1126 ((_ (x ...) e1 e2 ...)
1127 (let ((when-list (parse-when-list e #'(x ...)))
1128 (body #'(e1 e2 ...)))
1129 (define (recurse m esew)
1130 (parse body r w s m esew mod))
1133 (if (memq 'eval when-list)
1134 (recurse (if (memq 'expand when-list) 'c&e 'e)
1137 (if (memq 'expand when-list)
1138 (top-level-eval-hook
1139 (expand-top-sequence body r w s 'e '(eval) mod)
1142 ((memq 'load when-list)
1143 (if (or (memq 'compile when-list)
1144 (memq 'expand when-list)
1145 (and (eq? m 'c&e) (memq 'eval when-list)))
1146 (recurse 'c&e '(compile load))
1147 (if (memq m '(c c&e))
1148 (recurse 'c '(load))
1150 ((or (memq 'compile when-list)
1151 (memq 'expand when-list)
1152 (and (eq? m 'c&e) (memq 'eval when-list)))
1153 (top-level-eval-hook
1154 (expand-top-sequence body r w s 'e '(eval) mod)
1162 (let ((x (expand-expr type value form e r w s mod)))
1163 (top-level-eval-hook x mod)
1166 (expand-expr type value form e r w s mod)))))))))
1167 (let ((exps (map (lambda (x) (x))
1168 (reverse (parse body r w s m esew mod)))))
1171 (build-sequence s exps))))))
1173 (define expand-install-global
1174 (lambda (name type e)
1175 (build-global-definition
1180 'make-syntax-transformer
1181 (if (eq? type 'define-syntax-parameter-form)
1182 (list (build-data no-source name)
1183 (build-data no-source 'syntax-parameter)
1184 (build-primcall no-source 'list (list e)))
1185 (list (build-data no-source name)
1186 (build-data no-source 'macro)
1189 (define parse-when-list
1190 (lambda (e when-list)
1191 ;; `when-list' is syntax'd version of list of situations. We
1192 ;; could match these keywords lexically, via free-id=?, but then
1193 ;; we twingle the definition of eval-when to the bindings of
1194 ;; eval, load, expand, and compile, which is totally unintended.
1195 ;; So do a symbolic match instead.
1196 (let ((result (strip when-list empty-wrap)))
1197 (let lp ((l result))
1200 (if (memq (car l) '(compile load eval expand))
1202 (syntax-violation 'eval-when "invalid situation" e
1205 ;; syntax-type returns seven values: type, value, form, e, w, s, and
1206 ;; mod. The first two are described in the table below.
1208 ;; type value explanation
1209 ;; -------------------------------------------------------------------
1210 ;; core procedure core singleton
1211 ;; core-form procedure core form
1212 ;; module-ref procedure @ or @@ singleton
1213 ;; lexical name lexical variable reference
1214 ;; global name global variable reference
1215 ;; begin none begin keyword
1216 ;; define none define keyword
1217 ;; define-syntax none define-syntax keyword
1218 ;; define-syntax-parameter none define-syntax-parameter keyword
1219 ;; local-syntax rec? letrec-syntax/let-syntax keyword
1220 ;; eval-when none eval-when keyword
1221 ;; syntax level pattern variable
1222 ;; displaced-lexical none displaced lexical identifier
1223 ;; lexical-call name call to lexical variable
1224 ;; global-call name call to global variable
1225 ;; call none any other call
1226 ;; begin-form none begin expression
1227 ;; define-form id variable definition
1228 ;; define-syntax-form id syntax definition
1229 ;; define-syntax-parameter-form id syntax parameter definition
1230 ;; local-syntax-form rec? syntax definition
1231 ;; eval-when-form none eval-when form
1232 ;; constant none self-evaluating datum
1233 ;; other none anything else
1235 ;; form is the entire form. For definition forms (define-form,
1236 ;; define-syntax-form, and define-syntax-parameter-form), e is the
1237 ;; rhs expression. For all others, e is the entire form. w is the
1238 ;; wrap for both form and e. s is the source for the entire form.
1239 ;; mod is the module for both form and e.
1241 ;; syntax-type expands macros and unwraps as necessary to get to one
1242 ;; of the forms above. It also parses definition forms, although
1243 ;; perhaps this should be done by the consumer.
1246 (lambda (e r w s rib mod for-car?)
1249 (call-with-values (lambda () (resolve-identifier e w r mod #t))
1250 (lambda (type value mod*)
1254 (values type value e e w s mod)
1255 (syntax-type (expand-macro value e r w s rib mod)
1256 r empty-wrap s rib mod #f)))
1258 ;; Toplevel definitions may resolve to bindings with
1259 ;; different names or in different modules.
1260 (values type value e value w s mod*))
1261 (else (values type value e e w s mod))))))
1263 (let ((first (car e)))
1265 (lambda () (syntax-type first r w s rib mod #t))
1266 (lambda (ftype fval fform fe fw fs fmod)
1269 (values 'lexical-call fval e e w s mod))
1271 ;; If we got here via an (@@ ...) expansion, we need to
1272 ;; make sure the fmod information is propagated back
1273 ;; correctly -- hence this consing.
1274 (values 'global-call (make-syntax-object fval w fmod)
1277 (syntax-type (expand-macro fval e r w s rib mod)
1278 r empty-wrap s rib mod for-car?))
1280 (call-with-values (lambda () (fval e r w))
1281 (lambda (e r w s mod)
1282 (syntax-type e r w s rib mod for-car?))))
1284 (values 'core-form fval e e w s mod))
1286 (values 'local-syntax-form fval e e w s mod))
1288 (values 'begin-form #f e e w s mod))
1290 (values 'eval-when-form #f e e w s mod))
1295 (values 'define-form #'name e #'val w s mod))
1296 ((_ (name . args) e1 e2 ...)
1298 (valid-bound-ids? (lambda-var-list #'args)))
1299 ;; need lambda here...
1300 (values 'define-form (wrap #'name w mod)
1303 (cons #'lambda (wrap #'(args e1 e2 ...) w mod))
1308 (values 'define-form (wrap #'name w mod)
1311 empty-wrap s mod))))
1316 (values 'define-syntax-form #'name e #'val w s mod))))
1317 ((define-syntax-parameter)
1321 (values 'define-syntax-parameter-form #'name e #'val w s mod))))
1323 (values 'call #f e e w s mod)))))))
1325 (syntax-type (syntax-object-expression e)
1327 (join-wraps w (syntax-object-wrap e))
1328 (or (source-annotation e) s) rib
1329 (or (syntax-object-module e) mod) for-car?))
1330 ((self-evaluating? e) (values 'constant #f e e w s mod))
1331 (else (values 'other #f e e w s mod)))))
1336 (lambda () (syntax-type e r w (source-annotation e) #f mod #f))
1337 (lambda (type value form e w s mod)
1338 (expand-expr type value form e r w s mod)))))
1341 (lambda (type value form e r w s mod)
1344 (build-lexical-reference 'value s e value))
1346 ;; apply transformer
1347 (value e r w s mod))
1349 (call-with-values (lambda () (value e r w))
1350 (lambda (e r w s mod)
1351 (expand e r w mod))))
1355 (build-lexical-reference 'fun (source-annotation id)
1356 (if (syntax-object? id)
1363 (build-global-reference (source-annotation (car e))
1364 (if (syntax-object? value)
1365 (syntax-object-expression value)
1367 (if (syntax-object? value)
1368 (syntax-object-module value)
1371 ((constant) (build-data s (strip (source-wrap e w s mod) empty-wrap)))
1372 ((global) (build-global-reference s value mod))
1373 ((call) (expand-call (expand (car e) r w mod) e r w s mod))
1376 ((_ e1 e2 ...) (expand-sequence #'(e1 e2 ...) r w s mod))
1378 (syntax-violation #f "sequence of zero expressions"
1379 (source-wrap e w s mod)))))
1380 ((local-syntax-form)
1381 (expand-local-syntax value e r w s mod expand-sequence))
1384 ((_ (x ...) e1 e2 ...)
1385 (let ((when-list (parse-when-list e #'(x ...))))
1386 (if (memq 'eval when-list)
1387 (expand-sequence #'(e1 e2 ...) r w s mod)
1389 ((define-form define-syntax-form define-syntax-parameter-form)
1390 (syntax-violation #f "definition in expression context, where definitions are not allowed,"
1391 (source-wrap form w s mod)))
1393 (syntax-violation #f "reference to pattern variable outside syntax form"
1394 (source-wrap e w s mod)))
1395 ((displaced-lexical)
1396 (syntax-violation #f "reference to identifier outside its scope"
1397 (source-wrap e w s mod)))
1398 (else (syntax-violation #f "unexpected syntax"
1399 (source-wrap e w s mod))))))
1402 (lambda (x e r w s mod)
1406 (map (lambda (e) (expand e r w mod)) #'(e1 ...)))))))
1408 ;; (What follows is my interpretation of what's going on here -- Andy)
1410 ;; A macro takes an expression, a tree, the leaves of which are identifiers
1411 ;; and datums. Identifiers are symbols along with a wrap and a module. For
1412 ;; efficiency, subtrees that share wraps and modules may be grouped as one
1415 ;; Going into the expansion, the expression is given an anti-mark, which
1416 ;; logically propagates to all leaves. Then, in the new expression returned
1417 ;; from the transfomer, if we see an expression with an anti-mark, we know it
1418 ;; pertains to the original expression; conversely, expressions without the
1419 ;; anti-mark are known to be introduced by the transformer.
1421 ;; OK, good until now. We know this algorithm does lexical scoping
1422 ;; appropriately because it's widely known in the literature, and psyntax is
1423 ;; widely used. But what about modules? Here we're on our own. What we do is
1424 ;; to mark the module of expressions produced by a macro as pertaining to the
1425 ;; module that was current when the macro was defined -- that is, free
1426 ;; identifiers introduced by a macro are scoped in the macro's module, not in
1427 ;; the expansion's module. Seems to work well.
1429 ;; The only wrinkle is when we want a macro to expand to code in another
1430 ;; module, as is the case for the r6rs `library' form -- the body expressions
1431 ;; should be scoped relative the the new module, the one defined by the macro.
1432 ;; For that, use `(@@ mod-name body)'.
1434 ;; Part of the macro output will be from the site of the macro use and part
1435 ;; from the macro definition. We allow source information from the macro use
1436 ;; to pass through, but we annotate the parts coming from the macro with the
1437 ;; source location information corresponding to the macro use. It would be
1438 ;; really nice if we could also annotate introduced expressions with the
1439 ;; locations corresponding to the macro definition, but that is not yet
1441 (define expand-macro
1442 (lambda (p e r w s rib mod)
1443 (define rebuild-macro-output
1447 (cons (rebuild-macro-output (car x) m)
1448 (rebuild-macro-output (cdr x) m))
1451 (let ((w (syntax-object-wrap x)))
1452 (let ((ms (wrap-marks w)) (ss (wrap-subst w)))
1453 (if (and (pair? ms) (eq? (car ms) the-anti-mark))
1454 ;; output is from original text
1456 (syntax-object-expression x)
1457 (make-wrap (cdr ms) (if rib (cons rib (cdr ss)) (cdr ss)))
1458 (syntax-object-module x))
1459 ;; output introduced by macro
1461 (decorate-source (syntax-object-expression x) s)
1462 (make-wrap (cons m ms)
1464 (cons rib (cons 'shift ss))
1466 (syntax-object-module x))))))
1469 (let* ((n (vector-length x))
1470 (v (decorate-source (make-vector n) s)))
1471 (do ((i 0 (fx+ i 1)))
1474 (rebuild-macro-output (vector-ref x i) m)))))
1476 (syntax-violation #f "encountered raw symbol in macro output"
1477 (source-wrap e w (wrap-subst w) mod) x))
1478 (else (decorate-source x s)))))
1479 (with-fluids ((transformer-environment
1480 (lambda (k) (k e r w s rib mod))))
1481 (rebuild-macro-output (p (source-wrap e (anti-mark w) s mod))
1485 ;; In processing the forms of the body, we create a new, empty wrap.
1486 ;; This wrap is augmented (destructively) each time we discover that
1487 ;; the next form is a definition. This is done:
1489 ;; (1) to allow the first nondefinition form to be a call to
1490 ;; one of the defined ids even if the id previously denoted a
1491 ;; definition keyword or keyword for a macro expanding into a
1493 ;; (2) to prevent subsequent definition forms (but unfortunately
1494 ;; not earlier ones) and the first nondefinition form from
1495 ;; confusing one of the bound identifiers for an auxiliary
1497 ;; (3) so that we do not need to restart the expansion of the
1498 ;; first nondefinition form, which is problematic anyway
1499 ;; since it might be the first element of a begin that we
1500 ;; have just spliced into the body (meaning if we restarted,
1501 ;; we'd really need to restart with the begin or the macro
1502 ;; call that expanded into the begin, and we'd have to give
1503 ;; up allowing (begin <defn>+ <expr>+), which is itself
1504 ;; problematic since we don't know if a begin contains only
1505 ;; definitions until we've expanded it).
1507 ;; Before processing the body, we also create a new environment
1508 ;; containing a placeholder for the bindings we will add later and
1509 ;; associate this environment with each form. In processing a
1510 ;; let-syntax or letrec-syntax, the associated environment may be
1511 ;; augmented with local keyword bindings, so the environment may
1512 ;; be different for different forms in the body. Once we have
1513 ;; gathered up all of the definitions, we evaluate the transformer
1514 ;; expressions and splice into r at the placeholder the new variable
1515 ;; and keyword bindings. This allows let-syntax or letrec-syntax
1516 ;; forms local to a portion or all of the body to shadow the
1517 ;; definition bindings.
1519 ;; Subforms of a begin, let-syntax, or letrec-syntax are spliced
1522 ;; outer-form is fully wrapped w/source
1523 (lambda (body outer-form r w mod)
1524 (let* ((r (cons '("placeholder" . (placeholder)) r))
1525 (ribcage (make-empty-ribcage))
1526 (w (make-wrap (wrap-marks w) (cons ribcage (wrap-subst w)))))
1527 (let parse ((body (map (lambda (x) (cons r (wrap x w mod))) body))
1528 (ids '()) (labels '())
1529 (var-ids '()) (vars '()) (vals '()) (bindings '()))
1531 (syntax-violation #f "no expressions in body" outer-form)
1532 (let ((e (cdar body)) (er (caar body)))
1534 (lambda () (syntax-type e er empty-wrap (source-annotation er) ribcage mod #f))
1535 (lambda (type value form e w s mod)
1538 (let ((id (wrap value w mod)) (label (gen-label)))
1539 (let ((var (gen-var id)))
1540 (extend-ribcage! ribcage id label)
1542 (cons id ids) (cons label labels)
1544 (cons var vars) (cons (cons er (wrap e w mod)) vals)
1545 (cons (make-binding 'lexical var) bindings)))))
1546 ((define-syntax-form define-syntax-parameter-form)
1547 (let ((id (wrap value w mod)) (label (gen-label)))
1548 (extend-ribcage! ribcage id label)
1550 (cons id ids) (cons label labels)
1553 (if (eq? type 'define-syntax-parameter-form)
1556 (cons er (wrap e w mod)))
1561 (parse (let f ((forms #'(e1 ...)))
1564 (cons (cons er (wrap (car forms) w mod))
1566 ids labels var-ids vars vals bindings))))
1567 ((local-syntax-form)
1568 (expand-local-syntax value e er w s mod
1569 (lambda (forms er w s mod)
1570 (parse (let f ((forms forms))
1573 (cons (cons er (wrap (car forms) w mod))
1575 ids labels var-ids vars vals bindings))))
1576 (else ; found a non-definition
1578 (build-sequence no-source
1580 (expand (cdr x) (car x) empty-wrap mod))
1581 (cons (cons er (source-wrap e w s mod))
1584 (if (not (valid-bound-ids? ids))
1586 #f "invalid or duplicate identifier in definition"
1588 (let loop ((bs bindings) (er-cache #f) (r-cache #f))
1589 (if (not (null? bs))
1590 (let* ((b (car bs)))
1591 (if (memq (car b) '(macro syntax-parameter))
1592 (let* ((er (cadr b))
1594 (if (eq? er er-cache)
1596 (macros-only-env er))))
1598 (eval-local-transformer
1599 (expand (cddr b) r-cache empty-wrap mod)
1601 (if (eq? (car b) 'syntax-parameter)
1602 (set-cdr! b (list (cdr b))))
1603 (loop (cdr bs) er r-cache))
1604 (loop (cdr bs) er-cache r-cache)))))
1605 (set-cdr! r (extend-env labels bindings (cdr r)))
1606 (build-letrec no-source #t
1607 (reverse (map syntax->datum var-ids))
1610 (expand (cdr x) (car x) empty-wrap mod))
1612 (build-sequence no-source
1614 (expand (cdr x) (car x) empty-wrap mod))
1615 (cons (cons er (source-wrap e w s mod))
1616 (cdr body)))))))))))))))))
1618 (define expand-local-syntax
1619 (lambda (rec? e r w s mod k)
1621 ((_ ((id val) ...) e1 e2 ...)
1622 (let ((ids #'(id ...)))
1623 (if (not (valid-bound-ids? ids))
1624 (syntax-violation #f "duplicate bound keyword" e)
1625 (let ((labels (gen-labels ids)))
1626 (let ((new-w (make-binding-wrap ids labels w)))
1630 (let ((w (if rec? new-w w))
1631 (trans-r (macros-only-env r)))
1633 (make-binding 'macro
1634 (eval-local-transformer
1635 (expand x trans-r w mod)
1642 (_ (syntax-violation #f "bad local syntax definition"
1643 (source-wrap e w s mod))))))
1645 (define eval-local-transformer
1646 (lambda (expanded mod)
1647 (let ((p (local-eval-hook expanded mod)))
1650 (syntax-violation #f "nonprocedure transformer" p)))))
1654 (build-void no-source)))
1658 (and (nonsymbol-id? x)
1659 (free-id=? x #'(... ...)))))
1661 (define lambda-formals
1663 (define (req args rreq)
1664 (syntax-case args ()
1666 (check (reverse rreq) #f))
1668 (req #'b (cons #'a rreq)))
1670 (check (reverse rreq) #'r))
1672 (syntax-violation 'lambda "invalid argument list" orig-args args))))
1673 (define (check req rest)
1675 ((distinct-bound-ids? (if rest (cons rest req) req))
1676 (values req #f rest #f))
1678 (syntax-violation 'lambda "duplicate identifier in argument list"
1680 (req orig-args '())))
1682 (define expand-simple-lambda
1683 (lambda (e r w s mod req rest meta body)
1684 (let* ((ids (if rest (append req (list rest)) req))
1685 (vars (map gen-var ids))
1686 (labels (gen-labels ids)))
1687 (build-simple-lambda
1689 (map syntax->datum req) (and rest (syntax->datum rest)) vars
1691 (expand-body body (source-wrap e w s mod)
1692 (extend-var-env labels vars r)
1693 (make-binding-wrap ids labels w)
1696 (define lambda*-formals
1698 (define (req args rreq)
1699 (syntax-case args ()
1701 (check (reverse rreq) '() #f '()))
1703 (req #'b (cons #'a rreq)))
1704 ((a . b) (eq? (syntax->datum #'a) #:optional)
1705 (opt #'b (reverse rreq) '()))
1706 ((a . b) (eq? (syntax->datum #'a) #:key)
1707 (key #'b (reverse rreq) '() '()))
1708 ((a b) (eq? (syntax->datum #'a) #:rest)
1709 (rest #'b (reverse rreq) '() '()))
1711 (rest #'r (reverse rreq) '() '()))
1713 (syntax-violation 'lambda* "invalid argument list" orig-args args))))
1714 (define (opt args req ropt)
1715 (syntax-case args ()
1717 (check req (reverse ropt) #f '()))
1719 (opt #'b req (cons #'(a #f) ropt)))
1720 (((a init) . b) (id? #'a)
1721 (opt #'b req (cons #'(a init) ropt)))
1722 ((a . b) (eq? (syntax->datum #'a) #:key)
1723 (key #'b req (reverse ropt) '()))
1724 ((a b) (eq? (syntax->datum #'a) #:rest)
1725 (rest #'b req (reverse ropt) '()))
1727 (rest #'r req (reverse ropt) '()))
1729 (syntax-violation 'lambda* "invalid optional argument list"
1731 (define (key args req opt rkey)
1732 (syntax-case args ()
1734 (check req opt #f (cons #f (reverse rkey))))
1736 (with-syntax ((k (symbol->keyword (syntax->datum #'a))))
1737 (key #'b req opt (cons #'(k a #f) rkey))))
1738 (((a init) . b) (id? #'a)
1739 (with-syntax ((k (symbol->keyword (syntax->datum #'a))))
1740 (key #'b req opt (cons #'(k a init) rkey))))
1741 (((a init k) . b) (and (id? #'a)
1742 (keyword? (syntax->datum #'k)))
1743 (key #'b req opt (cons #'(k a init) rkey)))
1744 ((aok) (eq? (syntax->datum #'aok) #:allow-other-keys)
1745 (check req opt #f (cons #t (reverse rkey))))
1746 ((aok a b) (and (eq? (syntax->datum #'aok) #:allow-other-keys)
1747 (eq? (syntax->datum #'a) #:rest))
1748 (rest #'b req opt (cons #t (reverse rkey))))
1749 ((aok . r) (and (eq? (syntax->datum #'aok) #:allow-other-keys)
1751 (rest #'r req opt (cons #t (reverse rkey))))
1752 ((a b) (eq? (syntax->datum #'a) #:rest)
1753 (rest #'b req opt (cons #f (reverse rkey))))
1755 (rest #'r req opt (cons #f (reverse rkey))))
1757 (syntax-violation 'lambda* "invalid keyword argument list"
1759 (define (rest args req opt kw)
1760 (syntax-case args ()
1762 (check req opt #'r kw))
1764 (syntax-violation 'lambda* "invalid rest argument"
1766 (define (check req opt rest kw)
1768 ((distinct-bound-ids?
1769 (append req (map car opt) (if rest (list rest) '())
1770 (if (pair? kw) (map cadr (cdr kw)) '())))
1771 (values req opt rest kw))
1773 (syntax-violation 'lambda* "duplicate identifier in argument list"
1775 (req orig-args '())))
1777 (define expand-lambda-case
1778 (lambda (e r w s mod get-formals clauses)
1779 (define (parse-req req opt rest kw body)
1780 (let ((vars (map gen-var req))
1781 (labels (gen-labels req)))
1782 (let ((r* (extend-var-env labels vars r))
1783 (w* (make-binding-wrap req labels w)))
1784 (parse-opt (map syntax->datum req)
1785 opt rest kw body (reverse vars) r* w* '() '()))))
1786 (define (parse-opt req opt rest kw body vars r* w* out inits)
1789 (syntax-case (car opt) ()
1791 (let* ((v (gen-var #'id))
1792 (l (gen-labels (list v)))
1793 (r** (extend-var-env l (list v) r*))
1794 (w** (make-binding-wrap (list #'id) l w*)))
1795 (parse-opt req (cdr opt) rest kw body (cons v vars)
1796 r** w** (cons (syntax->datum #'id) out)
1797 (cons (expand #'i r* w* mod) inits))))))
1799 (let* ((v (gen-var rest))
1800 (l (gen-labels (list v)))
1801 (r* (extend-var-env l (list v) r*))
1802 (w* (make-binding-wrap (list rest) l w*)))
1803 (parse-kw req (if (pair? out) (reverse out) #f)
1804 (syntax->datum rest)
1805 (if (pair? kw) (cdr kw) kw)
1806 body (cons v vars) r* w*
1807 (if (pair? kw) (car kw) #f)
1810 (parse-kw req (if (pair? out) (reverse out) #f) #f
1811 (if (pair? kw) (cdr kw) kw)
1813 (if (pair? kw) (car kw) #f)
1815 (define (parse-kw req opt rest kw body vars r* w* aok out inits)
1818 (syntax-case (car kw) ()
1820 (let* ((v (gen-var #'id))
1821 (l (gen-labels (list v)))
1822 (r** (extend-var-env l (list v) r*))
1823 (w** (make-binding-wrap (list #'id) l w*)))
1824 (parse-kw req opt rest (cdr kw) body (cons v vars)
1826 (cons (list (syntax->datum #'k)
1827 (syntax->datum #'id)
1830 (cons (expand #'i r* w* mod) inits))))))
1832 (parse-body req opt rest
1833 (if (or aok (pair? out)) (cons aok (reverse out)) #f)
1834 body (reverse vars) r* w* (reverse inits) '()))))
1835 (define (parse-body req opt rest kw body vars r* w* inits meta)
1836 (syntax-case body ()
1837 ((docstring e1 e2 ...) (string? (syntax->datum #'docstring))
1838 (parse-body req opt rest kw #'(e1 e2 ...) vars r* w* inits
1841 . ,(syntax->datum #'docstring))))))
1842 ((#((k . v) ...) e1 e2 ...)
1843 (parse-body req opt rest kw #'(e1 e2 ...) vars r* w* inits
1844 (append meta (syntax->datum #'((k . v) ...)))))
1846 (values meta req opt rest kw inits vars
1847 (expand-body #'(e1 e2 ...) (source-wrap e w s mod)
1850 (syntax-case clauses ()
1851 (() (values '() #f))
1852 (((args e1 e2 ...) (args* e1* e2* ...) ...)
1853 (call-with-values (lambda () (get-formals #'args))
1854 (lambda (req opt rest kw)
1855 (call-with-values (lambda ()
1856 (parse-req req opt rest kw #'(e1 e2 ...)))
1857 (lambda (meta req opt rest kw inits vars body)
1860 (expand-lambda-case e r w s mod get-formals
1861 #'((args* e1* e2* ...) ...)))
1862 (lambda (meta* else*)
1865 (build-lambda-case s req opt rest kw inits vars
1866 body else*))))))))))))
1870 ;; strips syntax-objects down to top-wrap
1872 ;; since only the head of a list is annotated by the reader, not each pair
1873 ;; in the spine, we also check for pairs whose cars are annotated in case
1874 ;; we've been passed the cdr of an annotated list
1883 (strip (syntax-object-expression x) (syntax-object-wrap x)))
1885 (let ((a (f (car x))) (d (f (cdr x))))
1886 (if (and (eq? a (car x)) (eq? d (cdr x)))
1890 (let ((old (vector->list x)))
1891 (let ((new (map f old)))
1892 ;; inlined and-map with two args
1893 (let lp ((l1 old) (l2 new))
1896 (if (eq? (car l1) (car l2))
1897 (lp (cdr l1) (cdr l2))
1898 (list->vector new)))))))
1901 ;; lexical variables
1905 (let ((id (if (syntax-object? id) (syntax-object-expression id) id)))
1906 (build-lexical-var no-source id))))
1908 ;; appears to return a reversed list
1909 (define lambda-var-list
1911 (let lvl ((vars vars) (ls '()) (w empty-wrap))
1913 ((pair? vars) (lvl (cdr vars) (cons (wrap (car vars) w #f) ls) w))
1914 ((id? vars) (cons (wrap vars w #f) ls))
1916 ((syntax-object? vars)
1917 (lvl (syntax-object-expression vars)
1919 (join-wraps w (syntax-object-wrap vars))))
1920 ;; include anything else to be caught by subsequent error
1922 (else (cons vars ls))))))
1924 ;; core transformers
1926 (global-extend 'local-syntax 'letrec-syntax #t)
1927 (global-extend 'local-syntax 'let-syntax #f)
1930 'core 'syntax-parameterize
1931 (lambda (e r w s mod)
1933 ((_ ((var val) ...) e1 e2 ...)
1934 (valid-bound-ids? #'(var ...))
1938 (lambda () (resolve-identifier x w r mod #f))
1939 (lambda (type value mod)
1941 ((displaced-lexical)
1942 (syntax-violation 'syntax-parameterize
1943 "identifier out of context"
1945 (source-wrap x w s mod)))
1949 (syntax-violation 'syntax-parameterize
1950 "invalid syntax parameter"
1952 (source-wrap x w s mod)))))))
1955 (let ((trans-r (macros-only-env r)))
1959 (eval-local-transformer (expand x trans-r w mod) mod)))
1961 (expand-body #'(e1 e2 ...)
1962 (source-wrap e w s mod)
1963 (extend-env names bindings r)
1966 (_ (syntax-violation 'syntax-parameterize "bad syntax"
1967 (source-wrap e w s mod))))))
1969 (global-extend 'core 'quote
1970 (lambda (e r w s mod)
1972 ((_ e) (build-data s (strip #'e w)))
1973 (_ (syntax-violation 'quote "bad syntax"
1974 (source-wrap e w s mod))))))
1980 (lambda (src e r maps ellipsis? mod)
1982 (call-with-values (lambda ()
1983 (resolve-identifier e empty-wrap r mod #f))
1984 (lambda (type value mod)
1988 (lambda () (gen-ref src (car value) (cdr value) maps))
1990 (values `(ref ,var) maps))))
1993 (syntax-violation 'syntax "misplaced ellipsis" src)
1994 (values `(quote ,e) maps))))))
1998 (gen-syntax src #'e r maps (lambda (x) #f) mod))
2000 ;; this could be about a dozen lines of code, except that we
2001 ;; choose to handle #'(x ... ...) forms
2007 (gen-syntax src #'x r
2008 (cons '() maps) ellipsis? mod))
2010 (if (null? (car maps))
2011 (syntax-violation 'syntax "extra ellipsis"
2013 (values (gen-map x (car maps))
2021 (lambda () (k (cons '() maps)))
2023 (if (null? (car maps))
2024 (syntax-violation 'syntax "extra ellipsis" src)
2025 (values (gen-mappend x (car maps))
2027 (_ (call-with-values
2028 (lambda () (gen-syntax src y r maps ellipsis? mod))
2031 (lambda () (k maps))
2033 (values (gen-append x y) maps)))))))))
2036 (lambda () (gen-syntax src #'x r maps ellipsis? mod))
2039 (lambda () (gen-syntax src #'y r maps ellipsis? mod))
2040 (lambda (y maps) (values (gen-cons x y) maps))))))
2044 (gen-syntax src #'(e1 e2 ...) r maps ellipsis? mod))
2045 (lambda (e maps) (values (gen-vector e) maps))))
2046 (_ (values `(quote ,e) maps))))))
2049 (lambda (src var level maps)
2053 (syntax-violation 'syntax "missing ellipsis" src)
2055 (lambda () (gen-ref src var (fx- level 1) (cdr maps)))
2056 (lambda (outer-var outer-maps)
2057 (let ((b (assq outer-var (car maps))))
2059 (values (cdr b) maps)
2060 (let ((inner-var (gen-var 'tmp)))
2062 (cons (cons (cons outer-var inner-var)
2064 outer-maps)))))))))))
2068 `(apply (primitive append) ,(gen-map e map-env))))
2072 (let ((formals (map cdr map-env))
2073 (actuals (map (lambda (x) `(ref ,(car x))) map-env)))
2076 ;; identity map equivalence:
2077 ;; (map (lambda (x) x) y) == y
2080 (lambda (x) (and (eq? (car x) 'ref) (memq (cadr x) formals)))
2082 ;; eta map equivalence:
2083 ;; (map (lambda (x ...) (f x ...)) y ...) == (map f y ...)
2084 `(map (primitive ,(car e))
2085 ,@(map (let ((r (map cons formals actuals)))
2086 (lambda (x) (cdr (assq (cadr x) r))))
2088 (else `(map (lambda ,formals ,e) ,@actuals))))))
2094 (if (eq? (car x) 'quote)
2095 `(quote (,(cadr x) . ,(cadr y)))
2096 (if (eq? (cadr y) '())
2099 ((list) `(list ,x ,@(cdr y)))
2100 (else `(cons ,x ,y)))))
2104 (if (equal? y '(quote ()))
2111 ((eq? (car x) 'list) `(vector ,@(cdr x)))
2112 ((eq? (car x) 'quote) `(quote #(,@(cadr x))))
2113 (else `(list->vector ,x)))))
2119 ((ref) (build-lexical-reference 'value no-source (cadr x) (cadr x)))
2120 ((primitive) (build-primref no-source (cadr x)))
2121 ((quote) (build-data no-source (cadr x)))
2123 (if (list? (cadr x))
2124 (build-simple-lambda no-source (cadr x) #f (cadr x) '() (regen (caddr x)))
2125 (error "how did we get here" x)))
2126 (else (build-primcall no-source (car x) (map regen (cdr x)))))))
2128 (lambda (e r w s mod)
2129 (let ((e (source-wrap e w s mod)))
2133 (lambda () (gen-syntax e #'x r '() ellipsis? mod))
2134 (lambda (e maps) (regen e))))
2135 (_ (syntax-violation 'syntax "bad `syntax' form" e)))))))
2137 (global-extend 'core 'lambda
2138 (lambda (e r w s mod)
2141 (call-with-values (lambda () (lambda-formals #'args))
2142 (lambda (req opt rest kw)
2143 (let lp ((body #'(e1 e2 ...)) (meta '()))
2144 (syntax-case body ()
2145 ((docstring e1 e2 ...) (string? (syntax->datum #'docstring))
2149 . ,(syntax->datum #'docstring))))))
2150 ((#((k . v) ...) e1 e2 ...)
2152 (append meta (syntax->datum #'((k . v) ...)))))
2153 (_ (expand-simple-lambda e r w s mod req rest meta body)))))))
2154 (_ (syntax-violation 'lambda "bad lambda" e)))))
2156 (global-extend 'core 'lambda*
2157 (lambda (e r w s mod)
2162 (expand-lambda-case e r w s mod
2163 lambda*-formals #'((args e1 e2 ...))))
2164 (lambda (meta lcase)
2165 (build-case-lambda s meta lcase))))
2166 (_ (syntax-violation 'lambda "bad lambda*" e)))))
2168 (global-extend 'core 'case-lambda
2169 (lambda (e r w s mod)
2171 ((_ (args e1 e2 ...) (args* e1* e2* ...) ...)
2174 (expand-lambda-case e r w s mod
2176 #'((args e1 e2 ...) (args* e1* e2* ...) ...)))
2177 (lambda (meta lcase)
2178 (build-case-lambda s meta lcase))))
2179 (_ (syntax-violation 'case-lambda "bad case-lambda" e)))))
2181 (global-extend 'core 'case-lambda*
2182 (lambda (e r w s mod)
2184 ((_ (args e1 e2 ...) (args* e1* e2* ...) ...)
2187 (expand-lambda-case e r w s mod
2189 #'((args e1 e2 ...) (args* e1* e2* ...) ...)))
2190 (lambda (meta lcase)
2191 (build-case-lambda s meta lcase))))
2192 (_ (syntax-violation 'case-lambda "bad case-lambda*" e)))))
2194 (global-extend 'core 'let
2196 (define (expand-let e r w s mod constructor ids vals exps)
2197 (if (not (valid-bound-ids? ids))
2198 (syntax-violation 'let "duplicate bound variable" e)
2199 (let ((labels (gen-labels ids))
2200 (new-vars (map gen-var ids)))
2201 (let ((nw (make-binding-wrap ids labels w))
2202 (nr (extend-var-env labels new-vars r)))
2204 (map syntax->datum ids)
2206 (map (lambda (x) (expand x r w mod)) vals)
2207 (expand-body exps (source-wrap e nw s mod)
2209 (lambda (e r w s mod)
2211 ((_ ((id val) ...) e1 e2 ...)
2212 (and-map id? #'(id ...))
2213 (expand-let e r w s mod
2218 ((_ f ((id val) ...) e1 e2 ...)
2219 (and (id? #'f) (and-map id? #'(id ...)))
2220 (expand-let e r w s mod
2225 (_ (syntax-violation 'let "bad let" (source-wrap e w s mod)))))))
2228 (global-extend 'core 'letrec
2229 (lambda (e r w s mod)
2231 ((_ ((id val) ...) e1 e2 ...)
2232 (and-map id? #'(id ...))
2233 (let ((ids #'(id ...)))
2234 (if (not (valid-bound-ids? ids))
2235 (syntax-violation 'letrec "duplicate bound variable" e)
2236 (let ((labels (gen-labels ids))
2237 (new-vars (map gen-var ids)))
2238 (let ((w (make-binding-wrap ids labels w))
2239 (r (extend-var-env labels new-vars r)))
2241 (map syntax->datum ids)
2243 (map (lambda (x) (expand x r w mod)) #'(val ...))
2244 (expand-body #'(e1 e2 ...)
2245 (source-wrap e w s mod) r w mod)))))))
2246 (_ (syntax-violation 'letrec "bad letrec" (source-wrap e w s mod))))))
2249 (global-extend 'core 'letrec*
2250 (lambda (e r w s mod)
2252 ((_ ((id val) ...) e1 e2 ...)
2253 (and-map id? #'(id ...))
2254 (let ((ids #'(id ...)))
2255 (if (not (valid-bound-ids? ids))
2256 (syntax-violation 'letrec* "duplicate bound variable" e)
2257 (let ((labels (gen-labels ids))
2258 (new-vars (map gen-var ids)))
2259 (let ((w (make-binding-wrap ids labels w))
2260 (r (extend-var-env labels new-vars r)))
2262 (map syntax->datum ids)
2264 (map (lambda (x) (expand x r w mod)) #'(val ...))
2265 (expand-body #'(e1 e2 ...)
2266 (source-wrap e w s mod) r w mod)))))))
2267 (_ (syntax-violation 'letrec* "bad letrec*" (source-wrap e w s mod))))))
2272 (lambda (e r w s mod)
2277 (lambda () (resolve-identifier #'id w r mod #t))
2278 (lambda (type value id-mod)
2281 (build-lexical-assignment s (syntax->datum #'id) value
2282 (expand #'val r w mod)))
2284 (build-global-assignment s value (expand #'val r w mod) id-mod))
2286 (if (procedure-property value 'variable-transformer)
2287 ;; As syntax-type does, call expand-macro with
2288 ;; the mod of the expression. Hmm.
2289 (expand (expand-macro value e r w s #f mod) r empty-wrap mod)
2290 (syntax-violation 'set! "not a variable transformer"
2292 (wrap #'id w id-mod))))
2293 ((displaced-lexical)
2294 (syntax-violation 'set! "identifier out of context"
2297 (syntax-violation 'set! "bad set!" (source-wrap e w s mod)))))))
2298 ((_ (head tail ...) val)
2300 (lambda () (syntax-type #'head r empty-wrap no-source #f mod #t))
2301 (lambda (type value ee* ee ww ss modmod)
2304 (let ((val (expand #'val r w mod)))
2305 (call-with-values (lambda () (value #'(head tail ...) r w))
2306 (lambda (e r w s* mod)
2309 (build-global-assignment s (syntax->datum #'e)
2313 (expand #'(setter head) r w mod)
2314 (map (lambda (e) (expand e r w mod))
2315 #'(tail ... val))))))))
2316 (_ (syntax-violation 'set! "bad set!" (source-wrap e w s mod))))))
2318 (global-extend 'module-ref '@
2322 (and (and-map id? #'(mod ...)) (id? #'id))
2323 ;; Strip the wrap from the identifier and return top-wrap
2324 ;; so that the identifier will not be captured by lexicals.
2325 (values (syntax->datum #'id) r top-wrap #f
2327 #'(public mod ...)))))))
2329 (global-extend 'module-ref '@@
2334 (cons (remodulate (car x) mod)
2335 (remodulate (cdr x) mod)))
2338 (remodulate (syntax-object-expression x) mod)
2339 (syntax-object-wrap x)
2340 ;; hither the remodulation
2343 (let* ((n (vector-length x)) (v (make-vector n)))
2344 (do ((i 0 (fx+ i 1)))
2346 (vector-set! v i (remodulate (vector-ref x i) mod)))))
2350 (and (and-map id? #'(mod ...)) (id? #'id))
2351 ;; Strip the wrap from the identifier and return top-wrap
2352 ;; so that the identifier will not be captured by lexicals.
2353 (values (syntax->datum #'id) r top-wrap #f
2355 #'(private mod ...))))
2356 ((_ @@ (mod ...) exp)
2357 (and-map id? #'(mod ...))
2358 ;; This is a special syntax used to support R6RS library forms.
2359 ;; Unlike the syntax above, the last item is not restricted to
2360 ;; be a single identifier, and the syntax objects are kept
2361 ;; intact, with only their module changed.
2362 (let ((mod (syntax->datum #'(private mod ...))))
2363 (values (remodulate #'exp mod)
2364 r w (source-annotation #'exp)
2367 (global-extend 'core 'if
2368 (lambda (e r w s mod)
2373 (expand #'test r w mod)
2374 (expand #'then r w mod)
2375 (build-void no-source)))
2379 (expand #'test r w mod)
2380 (expand #'then r w mod)
2381 (expand #'else r w mod))))))
2383 (global-extend 'core 'with-fluids
2384 (lambda (e r w s mod)
2386 ((_ ((fluid val) ...) b b* ...)
2389 (map (lambda (x) (expand x r w mod)) #'(fluid ...))
2390 (map (lambda (x) (expand x r w mod)) #'(val ...))
2391 (expand-body #'(b b* ...)
2392 (source-wrap e w s mod) r w mod))))))
2394 (global-extend 'begin 'begin '())
2396 (global-extend 'define 'define '())
2398 (global-extend 'define-syntax 'define-syntax '())
2399 (global-extend 'define-syntax-parameter 'define-syntax-parameter '())
2401 (global-extend 'eval-when 'eval-when '())
2403 (global-extend 'core 'syntax-case
2405 (define convert-pattern
2406 ;; accepts pattern & keys
2407 ;; returns $sc-dispatch pattern & ids
2408 (lambda (pattern keys)
2411 (if (not (pair? p*))
2414 (lambda () (cvt* (cdr p*) n ids))
2417 (lambda () (cvt (car p*) n ids))
2419 (values (cons x y) ids))))))))
2421 (define (v-reverse x)
2422 (let loop ((r '()) (x x))
2425 (loop (cons (car x) r) (cdr x)))))
2431 ((bound-id-member? p keys)
2432 (values (vector 'free-id p) ids))
2436 (values 'any (cons (cons p n) ids))))
2439 (ellipsis? (syntax dots))
2441 (lambda () (cvt (syntax x) (fx+ n 1) ids))
2443 (values (if (eq? p 'any) 'each-any (vector 'each p))
2446 (ellipsis? (syntax dots))
2448 (lambda () (cvt* (syntax ys) n ids))
2451 (lambda () (cvt (syntax x) (+ n 1) ids))
2454 (lambda () (v-reverse ys))
2456 (values `#(each+ ,x ,ys ,e)
2460 (lambda () (cvt (syntax y) n ids))
2463 (lambda () (cvt (syntax x) n ids))
2465 (values (cons x y) ids))))))
2466 (() (values '() ids))
2469 (lambda () (cvt (syntax (x ...)) n ids))
2470 (lambda (p ids) (values (vector 'vector p) ids))))
2471 (x (values (vector 'atom (strip p empty-wrap)) ids))))))
2472 (cvt pattern 0 '())))
2474 (define build-dispatch-call
2475 (lambda (pvars exp y r mod)
2476 (let ((ids (map car pvars)) (levels (map cdr pvars)))
2477 (let ((labels (gen-labels ids)) (new-vars (map gen-var ids)))
2481 (list (build-simple-lambda no-source (map syntax->datum ids) #f new-vars '()
2485 (map (lambda (var level)
2486 (make-binding 'syntax `(,var . ,level)))
2490 (make-binding-wrap ids labels empty-wrap)
2495 (lambda (x keys clauses r pat fender exp mod)
2497 (lambda () (convert-pattern pat keys))
2500 ((not (distinct-bound-ids? (map car pvars)))
2501 (syntax-violation 'syntax-case "duplicate pattern variable" pat))
2502 ((not (and-map (lambda (x) (not (ellipsis? (car x)))) pvars))
2503 (syntax-violation 'syntax-case "misplaced ellipsis" pat))
2505 (let ((y (gen-var 'tmp)))
2506 ;; fat finger binding and references to temp variable y
2507 (build-call no-source
2508 (build-simple-lambda no-source (list 'tmp) #f (list y) '()
2509 (let ((y (build-lexical-reference 'value no-source
2511 (build-conditional no-source
2512 (syntax-case fender ()
2514 (_ (build-conditional no-source
2516 (build-dispatch-call pvars fender y r mod)
2517 (build-data no-source #f))))
2518 (build-dispatch-call pvars exp y r mod)
2519 (gen-syntax-case x keys clauses r mod))))
2520 (list (if (eq? p 'any)
2521 (build-primcall no-source 'list (list x))
2522 (build-primcall no-source '$sc-dispatch
2523 (list x (build-data no-source p)))))))))))))
2525 (define gen-syntax-case
2526 (lambda (x keys clauses r mod)
2528 (build-primcall no-source 'syntax-violation
2529 (list (build-data no-source #f)
2530 (build-data no-source
2531 "source expression failed to match any pattern")
2533 (syntax-case (car clauses) ()
2535 (if (and (id? #'pat)
2536 (and-map (lambda (x) (not (free-id=? #'pat x)))
2537 (cons #'(... ...) keys)))
2538 (if (free-id=? #'pat #'_)
2539 (expand #'exp r empty-wrap mod)
2540 (let ((labels (list (gen-label)))
2541 (var (gen-var #'pat)))
2542 (build-call no-source
2543 (build-simple-lambda
2544 no-source (list (syntax->datum #'pat)) #f (list var)
2548 (list (make-binding 'syntax `(,var . 0)))
2550 (make-binding-wrap #'(pat)
2554 (gen-clause x keys (cdr clauses) r
2555 #'pat #t #'exp mod)))
2557 (gen-clause x keys (cdr clauses) r
2558 #'pat #'fender #'exp mod))
2559 (_ (syntax-violation 'syntax-case "invalid clause"
2562 (lambda (e r w s mod)
2563 (let ((e (source-wrap e w s mod)))
2565 ((_ val (key ...) m ...)
2566 (if (and-map (lambda (x) (and (id? x) (not (ellipsis? x))))
2568 (let ((x (gen-var 'tmp)))
2569 ;; fat finger binding and references to temp variable x
2571 (build-simple-lambda no-source (list 'tmp) #f (list x) '()
2572 (gen-syntax-case (build-lexical-reference 'value no-source
2574 #'(key ...) #'(m ...)
2577 (list (expand #'val r empty-wrap mod))))
2578 (syntax-violation 'syntax-case "invalid literals list" e))))))))
2580 ;; The portable macroexpand seeds expand-top's mode m with 'e (for
2581 ;; evaluating) and esew (which stands for "eval syntax expanders
2582 ;; when") with '(eval). In Chez Scheme, m is set to 'c instead of e
2583 ;; if we are compiling a file, and esew is set to
2584 ;; (eval-syntactic-expanders-when), which defaults to the list
2585 ;; '(compile load eval). This means that, by default, top-level
2586 ;; syntactic definitions are evaluated immediately after they are
2587 ;; expanded, and the expanded definitions are also residualized into
2588 ;; the object file if we are compiling a file.
2590 (lambda* (x #:optional (m 'e) (esew '(eval)))
2591 (expand-top-sequence (list x) null-env top-wrap #f m esew
2592 (cons 'hygiene (module-name (current-module))))))
2600 (make-syntax-object datum (syntax-object-wrap id)
2601 (syntax-object-module id))))
2604 ;; accepts any object, since syntax objects may consist partially
2605 ;; or entirely of unwrapped, nonsymbolic data
2607 (strip x empty-wrap)))
2610 (lambda (x) (source-annotation x)))
2612 (set! generate-temporaries
2614 (arg-check list? ls 'generate-temporaries)
2615 (let ((mod (cons 'hygiene (module-name (current-module)))))
2616 (map (lambda (x) (wrap (gensym "t-") top-wrap mod)) ls))))
2618 (set! free-identifier=?
2620 (arg-check nonsymbol-id? x 'free-identifier=?)
2621 (arg-check nonsymbol-id? y 'free-identifier=?)
2624 (set! bound-identifier=?
2626 (arg-check nonsymbol-id? x 'bound-identifier=?)
2627 (arg-check nonsymbol-id? y 'bound-identifier=?)
2630 (set! syntax-violation
2631 (lambda* (who message form #:optional subform)
2632 (arg-check (lambda (x) (or (not x) (string? x) (symbol? x)))
2633 who 'syntax-violation)
2634 (arg-check string? message 'syntax-violation)
2635 (throw 'syntax-error who message
2636 (or (source-annotation subform)
2637 (source-annotation form))
2638 (strip form empty-wrap)
2639 (and subform (strip subform empty-wrap)))))
2642 (define (syntax-module id)
2643 (arg-check nonsymbol-id? id 'syntax-module)
2644 (cdr (syntax-object-module id)))
2646 (define (syntax-local-binding id)
2647 (arg-check nonsymbol-id? id 'syntax-local-binding)
2648 (with-transformer-environment
2649 (lambda (e r w s rib mod)
2650 (define (strip-anti-mark w)
2651 (let ((ms (wrap-marks w)) (s (wrap-subst w)))
2652 (if (and (pair? ms) (eq? (car ms) the-anti-mark))
2653 ;; output is from original text
2654 (make-wrap (cdr ms) (if rib (cons rib (cdr s)) (cdr s)))
2655 ;; output introduced by macro
2656 (make-wrap ms (if rib (cons rib s) s)))))
2657 (call-with-values (lambda ()
2659 (syntax-object-expression id)
2660 (strip-anti-mark (syntax-object-wrap id))
2662 (syntax-object-module id)
2663 ;; FIXME: come up with a better policy for
2664 ;; resolve-syntax-parameters
2666 (lambda (type value mod)
2668 ((lexical) (values 'lexical value))
2669 ((macro) (values 'macro value))
2670 ((syntax) (values 'pattern-variable value))
2671 ((displaced-lexical) (values 'displaced-lexical #f))
2672 ((global) (values 'global (cons value (cdr mod))))
2673 (else (values 'other #f))))))))
2675 (define (syntax-locally-bound-identifiers id)
2676 (arg-check nonsymbol-id? id 'syntax-locally-bound-identifiers)
2677 (locally-bound-identifiers (syntax-object-wrap id)
2678 (syntax-object-module id)))
2680 ;; Using define! instead of set! to avoid warnings at
2681 ;; compile-time, after the variables are stolen away into (system
2682 ;; syntax). See the end of boot-9.scm.
2684 (define! 'syntax-module syntax-module)
2685 (define! 'syntax-local-binding syntax-local-binding)
2686 (define! 'syntax-locally-bound-identifiers syntax-locally-bound-identifiers))
2688 ;; $sc-dispatch expects an expression and a pattern. If the expression
2689 ;; matches the pattern a list of the matching expressions for each
2690 ;; "any" is returned. Otherwise, #f is returned. (This use of #f will
2691 ;; not work on r4rs implementations that violate the ieee requirement
2692 ;; that #f and () be distinct.)
2694 ;; The expression is matched with the pattern as follows:
2696 ;; pattern: matches:
2699 ;; (<pattern>1 . <pattern>2) (<pattern>1 . <pattern>2)
2701 ;; #(free-id <key>) <key> with free-identifier=?
2702 ;; #(each <pattern>) (<pattern>*)
2703 ;; #(each+ p1 (p2_1 ... p2_n) p3) (p1* (p2_n ... p2_1) . p3)
2704 ;; #(vector <pattern>) (list->vector <pattern>)
2705 ;; #(atom <object>) <object> with "equal?"
2707 ;; Vector cops out to pair under assumption that vectors are rare. If
2708 ;; not, should convert to:
2709 ;; #(vector <pattern>*) #(<pattern>*)
2717 (let ((first (match (car e) p w '() mod)))
2719 (let ((rest (match-each (cdr e) p w mod)))
2720 (and rest (cons first rest))))))
2723 (match-each (syntax-object-expression e)
2725 (join-wraps w (syntax-object-wrap e))
2726 (syntax-object-module e)))
2730 (lambda (e x-pat y-pat z-pat w r mod)
2731 (let f ((e e) (w w))
2734 (call-with-values (lambda () (f (cdr e) w))
2735 (lambda (xr* y-pat r)
2738 (let ((xr (match (car e) x-pat w '() mod)))
2740 (values (cons xr xr*) y-pat r)
2745 (match (car e) (car y-pat) w r mod)))
2746 (values #f #f #f)))))
2748 (f (syntax-object-expression e) (join-wraps w e)))
2750 (values '() y-pat (match e z-pat w r mod)))))))
2752 (define match-each-any
2756 (let ((l (match-each-any (cdr e) w mod)))
2757 (and l (cons (wrap (car e) w mod) l))))
2760 (match-each-any (syntax-object-expression e)
2761 (join-wraps w (syntax-object-wrap e))
2770 ((eq? p 'any) (cons '() r))
2771 ((pair? p) (match-empty (car p) (match-empty (cdr p) r)))
2772 ((eq? p 'each-any) (cons '() r))
2774 (case (vector-ref p 0)
2775 ((each) (match-empty (vector-ref p 1) r))
2776 ((each+) (match-empty (vector-ref p 1)
2778 (reverse (vector-ref p 2))
2779 (match-empty (vector-ref p 3) r))))
2781 ((vector) (match-empty (vector-ref p 1) r)))))))
2785 (if (null? (car r*))
2787 (cons (map car r*) (combine (map cdr r*) r)))))
2790 (lambda (e p w r mod)
2792 ((null? p) (and (null? e) r))
2794 (and (pair? e) (match (car e) (car p) w
2795 (match (cdr e) (cdr p) w r mod)
2798 (let ((l (match-each-any e w mod))) (and l (cons l r))))
2800 (case (vector-ref p 0)
2803 (match-empty (vector-ref p 1) r)
2804 (let ((l (match-each e (vector-ref p 1) w mod)))
2806 (let collect ((l l))
2809 (cons (map car l) (collect (map cdr l)))))))))
2813 (match-each+ e (vector-ref p 1) (vector-ref p 2) (vector-ref p 3) w r mod))
2814 (lambda (xr* y-pat r)
2818 (match-empty (vector-ref p 1) r)
2819 (combine xr* r))))))
2820 ((free-id) (and (id? e) (free-id=? (wrap e w mod) (vector-ref p 1)) r))
2821 ((atom) (and (equal? (vector-ref p 1) (strip e w)) r))
2824 (match (vector->list e) (vector-ref p 1) w r mod))))))))
2827 (lambda (e p w r mod)
2831 ((eq? p 'any) (cons (wrap e w mod) r))
2834 (syntax-object-expression e)
2836 (join-wraps w (syntax-object-wrap e))
2838 (syntax-object-module e)))
2839 (else (match* e p w r mod)))))
2844 ((eq? p 'any) (list e))
2847 (match* (syntax-object-expression e)
2848 p (syntax-object-wrap e) '() (syntax-object-module e)))
2849 (else (match* e p empty-wrap '() #f))))))))
2852 (define-syntax with-syntax
2856 #'(let () e1 e2 ...))
2857 ((_ ((out in)) e1 e2 ...)
2858 #'(syntax-case in ()
2859 (out (let () e1 e2 ...))))
2860 ((_ ((out in) ...) e1 e2 ...)
2861 #'(syntax-case (list in ...) ()
2862 ((out ...) (let () e1 e2 ...)))))))
2864 (define-syntax syntax-rules
2867 ((_ (k ...) ((keyword . pattern) template) ...)
2869 ;; embed patterns as procedure metadata
2870 #((macro-type . syntax-rules)
2871 (patterns pattern ...))
2872 (syntax-case x (k ...)
2873 ((_ . pattern) #'template)
2875 ((_ (k ...) docstring ((keyword . pattern) template) ...)
2876 (string? (syntax->datum #'docstring))
2878 ;; the same, but allow a docstring
2880 #((macro-type . syntax-rules)
2881 (patterns pattern ...))
2882 (syntax-case x (k ...)
2883 ((_ . pattern) #'template)
2886 (define-syntax define-syntax-rule
2889 ((_ (name . pattern) template)
2890 #'(define-syntax name
2892 ((_ . pattern) template))))
2893 ((_ (name . pattern) docstring template)
2894 (string? (syntax->datum #'docstring))
2895 #'(define-syntax name
2898 ((_ . pattern) template)))))))
2903 ((let* ((x v) ...) e1 e2 ...)
2904 (and-map identifier? #'(x ...))
2905 (let f ((bindings #'((x v) ...)))
2906 (if (null? bindings)
2907 #'(let () e1 e2 ...)
2908 (with-syntax ((body (f (cdr bindings)))
2909 (binding (car bindings)))
2910 #'(let (binding) body))))))))
2912 (define-syntax quasiquote
2914 (define (quasi p lev)
2915 (syntax-case p (unquote quasiquote)
2919 (quasicons #'("quote" unquote) (quasi #'(p) (- lev 1)))))
2920 ((quasiquote p) (quasicons #'("quote" quasiquote) (quasi #'(p) (+ lev 1))))
2922 (syntax-case #'p (unquote unquote-splicing)
2925 (quasilist* #'(("value" p) ...) (quasi #'q lev))
2927 (quasicons #'("quote" unquote) (quasi #'(p ...) (- lev 1)))
2929 ((unquote-splicing p ...)
2931 (quasiappend #'(("value" p) ...) (quasi #'q lev))
2933 (quasicons #'("quote" unquote-splicing) (quasi #'(p ...) (- lev 1)))
2935 (_ (quasicons (quasi #'p lev) (quasi #'q lev)))))
2936 (#(x ...) (quasivector (vquasi #'(x ...) lev)))
2938 (define (vquasi p lev)
2941 (syntax-case #'p (unquote unquote-splicing)
2944 (quasilist* #'(("value" p) ...) (vquasi #'q lev))
2946 (quasicons #'("quote" unquote) (quasi #'(p ...) (- lev 1)))
2948 ((unquote-splicing p ...)
2950 (quasiappend #'(("value" p) ...) (vquasi #'q lev))
2953 #'("quote" unquote-splicing)
2954 (quasi #'(p ...) (- lev 1)))
2956 (_ (quasicons (quasi #'p lev) (vquasi #'q lev)))))
2957 (() #'("quote" ()))))
2958 (define (quasicons x y)
2959 (with-syntax ((x x) (y y))
2963 (("quote" dx) #'("quote" (dx . dy)))
2964 (_ (if (null? #'dy) #'("list" x) #'("list*" x y)))))
2965 (("list" . stuff) #'("list" x . stuff))
2966 (("list*" . stuff) #'("list*" x . stuff))
2967 (_ #'("list*" x y)))))
2968 (define (quasiappend x y)
2972 ((null? x) #'("quote" ()))
2973 ((null? (cdr x)) (car x))
2974 (else (with-syntax (((p ...) x)) #'("append" p ...)))))
2978 (else (with-syntax (((p ...) x) (y y)) #'("append" p ... y)))))))
2979 (define (quasilist* x y)
2983 (quasicons (car x) (f (cdr x))))))
2984 (define (quasivector x)
2986 (("quote" (x ...)) #'("quote" #(x ...)))
2988 (let f ((y x) (k (lambda (ls) #`("vector" #,@ls))))
2990 (("quote" (y ...)) (k #'(("quote" y) ...)))
2991 (("list" y ...) (k #'(y ...)))
2992 (("list*" y ... z) (f #'z (lambda (ls) (k (append #'(y ...) ls)))))
2993 (else #`("list->vector" #,x)))))))
2997 (("list" x ...) #`(list #,@(map emit #'(x ...))))
2998 ;; could emit list* for 3+ arguments if implementation supports
3001 (let f ((x* #'(x ...)))
3004 #`(cons #,(emit (car x*)) #,(f (cdr x*))))))
3005 (("append" x ...) #`(append #,@(map emit #'(x ...))))
3006 (("vector" x ...) #`(vector #,@(map emit #'(x ...))))
3007 (("list->vector" x) #`(list->vector #,(emit #'x)))
3011 ;; convert to intermediate language, combining introduced (but
3012 ;; not unquoted source) quote expressions where possible and
3013 ;; choosing optimal construction code otherwise, then emit
3014 ;; Scheme code corresponding to the intermediate language forms.
3015 ((_ e) (emit (quasi #'e 0)))))))
3017 (define-syntax include
3021 (let ((p (open-input-file fn)))
3022 (let f ((x (read p))
3026 (close-input-port p)
3029 (cons (datum->syntax k x) result)))))))
3032 (let ((fn (syntax->datum #'filename)))
3033 (with-syntax (((exp ...) (read-file fn #'filename)))
3034 #'(begin exp ...)))))))
3036 (define-syntax include-from-path
3040 (let ((fn (syntax->datum #'filename)))
3041 (with-syntax ((fn (datum->syntax
3043 (or (%search-load-path fn)
3044 (syntax-violation 'include-from-path
3045 "file not found in path"
3047 #'(include fn)))))))
3049 (define-syntax unquote
3051 (syntax-violation 'unquote
3052 "expression not valid outside of quasiquote"
3055 (define-syntax unquote-splicing
3057 (syntax-violation 'unquote-splicing
3058 "expression not valid outside of quasiquote"
3061 (define (make-variable-transformer proc)
3062 (if (procedure? proc)
3063 (let ((trans (lambda (x)
3064 #((macro-type . variable-transformer))
3066 (set-procedure-property! trans 'variable-transformer #t)
3068 (error "variable transformer not a procedure" proc)))
3070 (define-syntax identifier-syntax
3072 (syntax-case xx (set!)
3075 #((macro-type . identifier-syntax))
3081 #'(e x (... ...))))))
3082 ((_ (id exp1) ((set! var val) exp2))
3083 (and (identifier? #'id) (identifier? #'var))
3084 #'(make-variable-transformer
3086 #((macro-type . variable-transformer))
3087 (syntax-case x (set!)
3088 ((set! var val) #'exp2)
3089 ((id x (... ...)) #'(exp1 x (... ...)))
3090 (id (identifier? #'id) #'exp1))))))))
3092 (define-syntax define*
3095 ((_ (id . args) b0 b1 ...)
3096 #'(define id (lambda* args b0 b1 ...)))
3097 ((_ id val) (identifier? #'id)
3098 #'(define id val)))))