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> ::= #(<old name> <label> (<mark> ...))
614 ;; <shift> ::= positive fixnum
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 (define-syntax subst-rename? (identifier-syntax vector?))
621 (define-syntax-rule (rename-old x) (vector-ref x 0))
622 (define-syntax-rule (rename-new x) (vector-ref x 1))
623 (define-syntax-rule (rename-marks x) (vector-ref x 2))
624 (define-syntax-rule (make-rename old new marks)
625 (vector old new marks))
627 ;; labels must be comparable with "eq?", have read-write invariance,
628 ;; and distinct from symbols.
630 (string-append "l-" (session-id) (symbol->string (gensym "-"))))
636 (cons (gen-label) (gen-labels (cdr ls))))))
638 (define-structure (ribcage symnames marks labels))
640 (define-syntax empty-wrap (identifier-syntax '(())))
642 (define-syntax top-wrap (identifier-syntax '((top))))
644 (define-syntax-rule (top-marked? w)
645 (memq 'top (wrap-marks w)))
647 ;; Marks must be comparable with "eq?" and distinct from pairs and
648 ;; the symbol top. We do not use integers so that marks will remain
649 ;; unique even across file compiles.
651 (define-syntax the-anti-mark (identifier-syntax #f))
655 (make-wrap (cons the-anti-mark (wrap-marks w))
656 (cons 'shift (wrap-subst w)))))
658 (define-syntax-rule (new-mark)
659 (gensym (string-append "m-" (session-id) "-")))
661 ;; make-empty-ribcage and extend-ribcage maintain list-based ribcages for
662 ;; internal definitions, in which the ribcages are built incrementally
663 (define-syntax-rule (make-empty-ribcage)
664 (make-ribcage '() '() '()))
666 (define extend-ribcage!
667 ;; must receive ids with complete wraps
668 (lambda (ribcage id label)
669 (set-ribcage-symnames! ribcage
670 (cons (syntax-object-expression id)
671 (ribcage-symnames ribcage)))
672 (set-ribcage-marks! ribcage
673 (cons (wrap-marks (syntax-object-wrap id))
674 (ribcage-marks ribcage)))
675 (set-ribcage-labels! ribcage
676 (cons label (ribcage-labels ribcage)))))
678 ;; make-binding-wrap creates vector-based ribcages
679 (define make-binding-wrap
680 (lambda (ids labels w)
686 (let ((labelvec (list->vector labels)))
687 (let ((n (vector-length labelvec)))
688 (let ((symnamevec (make-vector n)) (marksvec (make-vector n)))
689 (let f ((ids ids) (i 0))
690 (if (not (null? ids))
692 (lambda () (id-sym-name&marks (car ids) w))
693 (lambda (symname marks)
694 (vector-set! symnamevec i symname)
695 (vector-set! marksvec i marks)
696 (f (cdr ids) (fx+ i 1))))))
697 (make-ribcage symnamevec marksvec labelvec))))
708 (let ((m1 (wrap-marks w1)) (s1 (wrap-subst w1)))
714 (smart-append s1 (wrap-subst w2))))
716 (smart-append m1 (wrap-marks w2))
717 (smart-append s1 (wrap-subst w2)))))))
721 (smart-append m1 m2)))
728 (eq? (car x) (car y))
729 (same-marks? (cdr x) (cdr y))))))
732 ;; Syntax objects use wraps to associate names with marked
733 ;; identifiers. This function returns the name corresponding to
734 ;; the given identifier and wrap, or the original identifier if no
735 ;; corresponding name was found.
737 ;; The name may be a string created by gen-label, indicating a
738 ;; lexical binding, or another syntax object, indicating a
739 ;; reference to a top-level definition created during a previous
742 ;; For lexical variables, finding a label simply amounts to
743 ;; looking for an entry with the same symbolic name and the same
744 ;; marks. Finding a toplevel definition is the same, except we
745 ;; also have to compare modules, hence the `mod' parameter.
746 ;; Instead of adding a separate entry in the ribcage for modules,
747 ;; which wouldn't be used for lexicals, we arrange for the entry
748 ;; for the name entry to be a pair with the module in its car, and
749 ;; the name itself in the cdr. So if the name that we find is a
750 ;; pair, we have to check modules.
752 ;; The identifer may be passed in wrapped or unwrapped. In any
753 ;; case, this routine returns either a symbol, a syntax object, or
757 (define-syntax-rule (first e)
758 ;; Rely on Guile's multiple-values truncation.
761 (lambda (sym subst marks mod)
764 (let ((fst (car subst)))
766 (search sym (cdr subst) (cdr marks) mod)
767 (let ((symnames (ribcage-symnames fst)))
768 (if (vector? symnames)
769 (search-vector-rib sym subst marks symnames fst mod)
770 (search-list-rib sym subst marks symnames fst mod))))))))
771 (define search-list-rib
772 (lambda (sym subst marks symnames ribcage mod)
773 (let f ((symnames symnames) (i 0))
775 ((null? symnames) (search sym (cdr subst) marks mod))
776 ((and (eq? (car symnames) sym)
777 (same-marks? marks (list-ref (ribcage-marks ribcage) i)))
778 (let ((n (list-ref (ribcage-labels ribcage) i)))
780 (if (equal? mod (car n))
781 (values (cdr n) marks)
782 (f (cdr symnames) (fx+ i 1)))
784 (else (f (cdr symnames) (fx+ i 1)))))))
785 (define search-vector-rib
786 (lambda (sym subst marks symnames ribcage mod)
787 (let ((n (vector-length symnames)))
790 ((fx= i n) (search sym (cdr subst) marks mod))
791 ((and (eq? (vector-ref symnames i) sym)
792 (same-marks? marks (vector-ref (ribcage-marks ribcage) i)))
793 (let ((n (vector-ref (ribcage-labels ribcage) i)))
795 (if (equal? mod (car n))
796 (values (cdr n) marks)
799 (else (f (fx+ i 1))))))))
802 (or (first (search id (wrap-subst w) (wrap-marks w) mod)) id))
804 (let ((id (syntax-object-expression id))
805 (w1 (syntax-object-wrap id))
806 (mod (syntax-object-module id)))
807 (let ((marks (join-marks (wrap-marks w) (wrap-marks w1))))
808 (call-with-values (lambda () (search id (wrap-subst w) marks mod))
809 (lambda (new-id marks)
811 (first (search id (wrap-subst w1) marks mod))
813 (else (syntax-violation 'id-var-name "invalid id" id)))))
815 ;; A helper procedure for syntax-locally-bound-identifiers, which
816 ;; itself is a helper for transformer procedures.
817 ;; `locally-bound-identifiers' returns a list of all bindings
818 ;; visible to a syntax object with the given wrap. They are in
819 ;; order from outer to inner.
821 ;; The purpose of this procedure is to give a transformer procedure
822 ;; references on bound identifiers, that the transformer can then
823 ;; introduce some of them in its output. As such, the identifiers
824 ;; are anti-marked, so that rebuild-macro-output doesn't apply new
827 (define locally-bound-identifiers
830 (lambda (subst results)
833 (let ((fst (car subst)))
835 (scan (cdr subst) results)
836 (let ((symnames (ribcage-symnames fst))
837 (marks (ribcage-marks fst)))
838 (if (vector? symnames)
839 (scan-vector-rib subst symnames marks results)
840 (scan-list-rib subst symnames marks results))))))))
841 (define scan-list-rib
842 (lambda (subst symnames marks results)
843 (let f ((symnames symnames) (marks marks) (results results))
845 (scan (cdr subst) results)
846 (f (cdr symnames) (cdr marks)
847 (cons (wrap (car symnames)
848 (anti-mark (make-wrap (car marks) subst))
851 (define scan-vector-rib
852 (lambda (subst symnames marks results)
853 (let ((n (vector-length symnames)))
854 (let f ((i 0) (results results))
856 (scan (cdr subst) results)
858 (cons (wrap (vector-ref symnames i)
859 (anti-mark (make-wrap (vector-ref marks i) subst))
862 (scan (wrap-subst w) '())))
864 ;; Returns three values: binding type, binding value, the module (for
865 ;; resolving toplevel vars).
866 (define (resolve-identifier id w r mod resolve-syntax-parameters?)
867 (define (resolve-syntax-parameters b)
868 (if (and resolve-syntax-parameters?
869 (eq? (binding-type b) 'syntax-parameter))
870 (or (assq-ref r (binding-value b))
871 (make-binding 'macro (car (binding-value b))))
873 (define (resolve-global var mod)
874 (let ((b (resolve-syntax-parameters
875 (or (get-global-definition-hook var mod)
876 (make-binding 'global)))))
877 (if (eq? (binding-type b) 'global)
878 (values 'global var mod)
879 (values (binding-type b) (binding-value b) mod))))
880 (define (resolve-lexical label mod)
881 (let ((b (resolve-syntax-parameters
882 (or (assq-ref r label)
883 (make-binding 'displaced-lexical)))))
884 (values (binding-type b) (binding-value b) mod)))
885 (let ((n (id-var-name id w mod)))
888 ;; Recursing allows syntax-parameterize to override
889 ;; macro-introduced syntax parameters.
890 (resolve-identifier n w r mod resolve-syntax-parameters?))
892 (resolve-global n (if (syntax-object? id)
893 (syntax-object-module id)
896 (resolve-lexical n (if (syntax-object? id)
897 (syntax-object-module id)
900 (error "unexpected id-var-name" id w n)))))
902 (define transformer-environment
905 (error "called outside the dynamic extent of a syntax transformer"))))
907 (define (with-transformer-environment k)
908 ((fluid-ref transformer-environment) k))
910 ;; free-id=? must be passed fully wrapped ids since (free-id=? x y)
911 ;; may be true even if (free-id=? (wrap x w) (wrap y w)) is not.
915 (let* ((mi (and (syntax-object? i) (syntax-object-module i)))
916 (mj (and (syntax-object? j) (syntax-object-module j)))
917 (ni (id-var-name i empty-wrap mi))
918 (nj (id-var-name j empty-wrap mj)))
919 (define (id-module-binding id mod)
923 (resolve-module (cdr mod))
924 ;; Either modules have not been booted, or we have a
925 ;; raw symbol coming in, which is possible.
929 ((syntax-object? ni) (free-id=? ni j))
930 ((syntax-object? nj) (free-id=? i nj))
932 ;; `i' is not lexically bound. Assert that `j' is free,
933 ;; and if so, compare their bindings, that they are either
934 ;; bound to the same variable, or both unbound and have
936 (and (eq? nj (id-sym-name j))
937 (let ((bi (id-module-binding i mi)))
939 (eq? bi (id-module-binding j mj))
940 (and (not (id-module-binding j mj))
942 (eq? (id-module-binding i mi) (id-module-binding j mj))))
944 ;; Otherwise `i' is bound, so check that `j' is bound, and
945 ;; bound to the same thing.
948 ;; bound-id=? may be passed unwrapped (or partially wrapped) ids as
949 ;; long as the missing portion of the wrap is common to both of the ids
950 ;; since (bound-id=? x y) iff (bound-id=? (wrap x w) (wrap y w))
954 (if (and (syntax-object? i) (syntax-object? j))
955 (and (eq? (syntax-object-expression i)
956 (syntax-object-expression j))
957 (same-marks? (wrap-marks (syntax-object-wrap i))
958 (wrap-marks (syntax-object-wrap j))))
961 ;; "valid-bound-ids?" returns #t if it receives a list of distinct ids.
962 ;; valid-bound-ids? may be passed unwrapped (or partially wrapped) ids
963 ;; as long as the missing portion of the wrap is common to all of the
966 (define valid-bound-ids?
968 (and (let all-ids? ((ids ids))
971 (all-ids? (cdr ids)))))
972 (distinct-bound-ids? ids))))
974 ;; distinct-bound-ids? expects a list of ids and returns #t if there are
975 ;; no duplicates. It is quadratic on the length of the id list; long
976 ;; lists could be sorted to make it more efficient. distinct-bound-ids?
977 ;; may be passed unwrapped (or partially wrapped) ids as long as the
978 ;; missing portion of the wrap is common to all of the ids.
980 (define distinct-bound-ids?
982 (let distinct? ((ids ids))
984 (and (not (bound-id-member? (car ids) (cdr ids)))
985 (distinct? (cdr ids)))))))
987 (define bound-id-member?
989 (and (not (null? list))
990 (or (bound-id=? x (car list))
991 (bound-id-member? x (cdr list))))))
993 ;; wrapping expressions and identifiers
998 ((and (null? (wrap-marks w)) (null? (wrap-subst w))) x)
1001 (syntax-object-expression x)
1002 (join-wraps w (syntax-object-wrap x))
1003 (syntax-object-module x)))
1005 (else (make-syntax-object x w defmod)))))
1008 (lambda (x w s defmod)
1009 (wrap (decorate-source x s) w defmod)))
1013 (define expand-sequence
1014 (lambda (body r w s mod)
1016 (let dobody ((body body) (r r) (w w) (mod mod))
1019 (let ((first (expand (car body) r w mod)))
1020 (cons first (dobody (cdr body) r w mod))))))))
1022 ;; At top-level, we allow mixed definitions and expressions. Like
1023 ;; expand-body we expand in two passes.
1025 ;; First, from left to right, we expand just enough to know what
1026 ;; expressions are definitions, syntax definitions, and splicing
1027 ;; statements (`begin'). If we anything needs evaluating at
1028 ;; expansion-time, it is expanded directly.
1030 ;; Otherwise we collect expressions to expand, in thunks, and then
1031 ;; expand them all at the end. This allows all syntax expanders
1032 ;; visible in a toplevel sequence to be visible during the
1033 ;; expansions of all normal definitions and expressions in the
1036 (define expand-top-sequence
1037 (lambda (body r w s m esew mod)
1038 (let* ((r (cons '("placeholder" . (placeholder)) r))
1039 (ribcage (make-empty-ribcage))
1040 (w (make-wrap (wrap-marks w) (cons ribcage (wrap-subst w)))))
1041 (define (record-definition! id var)
1042 (let ((mod (cons 'hygiene (module-name (current-module)))))
1043 ;; Ribcages map symbol+marks to names, mostly for
1044 ;; resolving lexicals. Here to add a mapping for toplevel
1045 ;; definitions we also need to match the module. So, we
1046 ;; put it in the name instead, and make id-var-name handle
1047 ;; the special case of names that are pairs. See the
1048 ;; comments in id-var-name for more.
1049 (extend-ribcage! ribcage id
1050 (cons (syntax-object-module id)
1051 (wrap var top-wrap mod)))))
1052 (define (macro-introduced-identifier? id)
1053 (not (equal? (wrap-marks (syntax-object-wrap id)) '(top))))
1054 (define (fresh-derived-name id orig-form)
1056 (syntax-object-expression id)
1059 ;; FIXME: `hash' currently stops descending into nested
1060 ;; data at some point, so it's less unique than we would
1061 ;; like. Also this encodes hash values into the ABI of
1062 ;; compiled modules; a problem?
1064 (hash (syntax->datum orig-form) most-positive-fixnum)
1066 (define (parse body r w s m esew mod)
1067 (let lp ((body body) (exps '()))
1071 (append (parse1 (car body) r w s m esew mod)
1073 (define (parse1 x r w s m esew mod)
1076 (syntax-type x r w (source-annotation x) ribcage mod #f))
1077 (lambda (type value form e w s mod)
1080 (let* ((id (wrap value w mod))
1082 (var (if (macro-introduced-identifier? id)
1083 (fresh-derived-name id x)
1084 (syntax-object-expression id))))
1085 (record-definition! id var)
1088 (let ((x (build-global-definition s var (expand e r w mod))))
1089 (top-level-eval-hook x mod)
1092 (build-global-definition s var (expand e r w mod)))))))
1093 ((define-syntax-form define-syntax-parameter-form)
1094 (let* ((id (wrap value w mod))
1096 (var (if (macro-introduced-identifier? id)
1097 (fresh-derived-name id x)
1098 (syntax-object-expression id))))
1099 (record-definition! id var)
1103 ((memq 'compile esew)
1104 (let ((e (expand-install-global var type (expand e r w mod))))
1105 (top-level-eval-hook e mod)
1106 (if (memq 'load esew)
1107 (list (lambda () e))
1111 (expand-install-global var type (expand e r w mod)))))
1114 (let ((e (expand-install-global var type (expand e r w mod))))
1115 (top-level-eval-hook e mod)
1116 (list (lambda () e))))
1118 (if (memq 'eval esew)
1119 (top-level-eval-hook
1120 (expand-install-global var type (expand e r w mod))
1126 (parse #'(e1 ...) r w s m esew mod))))
1127 ((local-syntax-form)
1128 (expand-local-syntax value e r w s mod
1129 (lambda (forms r w s mod)
1130 (parse forms r w s m esew mod))))
1133 ((_ (x ...) e1 e2 ...)
1134 (let ((when-list (parse-when-list e #'(x ...)))
1135 (body #'(e1 e2 ...)))
1136 (define (recurse m esew)
1137 (parse body r w s m esew mod))
1140 (if (memq 'eval when-list)
1141 (recurse (if (memq 'expand when-list) 'c&e 'e)
1144 (if (memq 'expand when-list)
1145 (top-level-eval-hook
1146 (expand-top-sequence body r w s 'e '(eval) mod)
1149 ((memq 'load when-list)
1150 (if (or (memq 'compile when-list)
1151 (memq 'expand when-list)
1152 (and (eq? m 'c&e) (memq 'eval when-list)))
1153 (recurse 'c&e '(compile load))
1154 (if (memq m '(c c&e))
1155 (recurse 'c '(load))
1157 ((or (memq 'compile when-list)
1158 (memq 'expand when-list)
1159 (and (eq? m 'c&e) (memq 'eval when-list)))
1160 (top-level-eval-hook
1161 (expand-top-sequence body r w s 'e '(eval) mod)
1169 (let ((x (expand-expr type value form e r w s mod)))
1170 (top-level-eval-hook x mod)
1173 (expand-expr type value form e r w s mod)))))))))
1174 (let ((exps (map (lambda (x) (x))
1175 (reverse (parse body r w s m esew mod)))))
1178 (build-sequence s exps))))))
1180 (define expand-install-global
1181 (lambda (name type e)
1182 (build-global-definition
1187 'make-syntax-transformer
1188 (if (eq? type 'define-syntax-parameter-form)
1189 (list (build-data no-source name)
1190 (build-data no-source 'syntax-parameter)
1191 (build-primcall no-source 'list (list e)))
1192 (list (build-data no-source name)
1193 (build-data no-source 'macro)
1196 (define parse-when-list
1197 (lambda (e when-list)
1198 ;; `when-list' is syntax'd version of list of situations. We
1199 ;; could match these keywords lexically, via free-id=?, but then
1200 ;; we twingle the definition of eval-when to the bindings of
1201 ;; eval, load, expand, and compile, which is totally unintended.
1202 ;; So do a symbolic match instead.
1203 (let ((result (strip when-list empty-wrap)))
1204 (let lp ((l result))
1207 (if (memq (car l) '(compile load eval expand))
1209 (syntax-violation 'eval-when "invalid situation" e
1212 ;; syntax-type returns seven values: type, value, form, e, w, s, and
1213 ;; mod. The first two are described in the table below.
1215 ;; type value explanation
1216 ;; -------------------------------------------------------------------
1217 ;; core procedure core singleton
1218 ;; core-form procedure core form
1219 ;; module-ref procedure @ or @@ singleton
1220 ;; lexical name lexical variable reference
1221 ;; global name global variable reference
1222 ;; begin none begin keyword
1223 ;; define none define keyword
1224 ;; define-syntax none define-syntax keyword
1225 ;; define-syntax-parameter none define-syntax-parameter keyword
1226 ;; local-syntax rec? letrec-syntax/let-syntax keyword
1227 ;; eval-when none eval-when keyword
1228 ;; syntax level pattern variable
1229 ;; displaced-lexical none displaced lexical identifier
1230 ;; lexical-call name call to lexical variable
1231 ;; global-call name call to global variable
1232 ;; call none any other call
1233 ;; begin-form none begin expression
1234 ;; define-form id variable definition
1235 ;; define-syntax-form id syntax definition
1236 ;; define-syntax-parameter-form id syntax parameter definition
1237 ;; local-syntax-form rec? syntax definition
1238 ;; eval-when-form none eval-when form
1239 ;; constant none self-evaluating datum
1240 ;; other none anything else
1242 ;; form is the entire form. For definition forms (define-form,
1243 ;; define-syntax-form, and define-syntax-parameter-form), e is the
1244 ;; rhs expression. For all others, e is the entire form. w is the
1245 ;; wrap for both form and e. s is the source for the entire form.
1246 ;; mod is the module for both form and e.
1248 ;; syntax-type expands macros and unwraps as necessary to get to one
1249 ;; of the forms above. It also parses definition forms, although
1250 ;; perhaps this should be done by the consumer.
1253 (lambda (e r w s rib mod for-car?)
1256 (call-with-values (lambda () (resolve-identifier e w r mod #t))
1257 (lambda (type value mod*)
1261 (values type value e e w s mod)
1262 (syntax-type (expand-macro value e r w s rib mod)
1263 r empty-wrap s rib mod #f)))
1265 ;; Toplevel definitions may resolve to bindings with
1266 ;; different names or in different modules.
1267 (values type value e value w s mod*))
1268 (else (values type value e e w s mod))))))
1270 (let ((first (car e)))
1272 (lambda () (syntax-type first r w s rib mod #t))
1273 (lambda (ftype fval fform fe fw fs fmod)
1276 (values 'lexical-call fval e e w s mod))
1278 ;; If we got here via an (@@ ...) expansion, we need to
1279 ;; make sure the fmod information is propagated back
1280 ;; correctly -- hence this consing.
1281 (values 'global-call (make-syntax-object fval w fmod)
1284 (syntax-type (expand-macro fval e r w s rib mod)
1285 r empty-wrap s rib mod for-car?))
1287 (call-with-values (lambda () (fval e r w))
1288 (lambda (e r w s mod)
1289 (syntax-type e r w s rib mod for-car?))))
1291 (values 'core-form fval e e w s mod))
1293 (values 'local-syntax-form fval e e w s mod))
1295 (values 'begin-form #f e e w s mod))
1297 (values 'eval-when-form #f e e w s mod))
1302 (values 'define-form #'name e #'val w s mod))
1303 ((_ (name . args) e1 e2 ...)
1305 (valid-bound-ids? (lambda-var-list #'args)))
1306 ;; need lambda here...
1307 (values 'define-form (wrap #'name w mod)
1310 (cons #'lambda (wrap #'(args e1 e2 ...) w mod))
1315 (values 'define-form (wrap #'name w mod)
1318 empty-wrap s mod))))
1323 (values 'define-syntax-form #'name e #'val w s mod))))
1324 ((define-syntax-parameter)
1328 (values 'define-syntax-parameter-form #'name e #'val w s mod))))
1330 (values 'call #f e e w s mod)))))))
1332 (syntax-type (syntax-object-expression e)
1334 (join-wraps w (syntax-object-wrap e))
1335 (or (source-annotation e) s) rib
1336 (or (syntax-object-module e) mod) for-car?))
1337 ((self-evaluating? e) (values 'constant #f e e w s mod))
1338 (else (values 'other #f e e w s mod)))))
1343 (lambda () (syntax-type e r w (source-annotation e) #f mod #f))
1344 (lambda (type value form e w s mod)
1345 (expand-expr type value form e r w s mod)))))
1348 (lambda (type value form e r w s mod)
1351 (build-lexical-reference 'value s e value))
1353 ;; apply transformer
1354 (value e r w s mod))
1356 (call-with-values (lambda () (value e r w))
1357 (lambda (e r w s mod)
1358 (expand e r w mod))))
1362 (build-lexical-reference 'fun (source-annotation id)
1363 (if (syntax-object? id)
1370 (build-global-reference (source-annotation (car e))
1371 (if (syntax-object? value)
1372 (syntax-object-expression value)
1374 (if (syntax-object? value)
1375 (syntax-object-module value)
1378 ((constant) (build-data s (strip (source-wrap e w s mod) empty-wrap)))
1379 ((global) (build-global-reference s value mod))
1380 ((call) (expand-call (expand (car e) r w mod) e r w s mod))
1383 ((_ e1 e2 ...) (expand-sequence #'(e1 e2 ...) r w s mod))
1385 (syntax-violation #f "sequence of zero expressions"
1386 (source-wrap e w s mod)))))
1387 ((local-syntax-form)
1388 (expand-local-syntax value e r w s mod expand-sequence))
1391 ((_ (x ...) e1 e2 ...)
1392 (let ((when-list (parse-when-list e #'(x ...))))
1393 (if (memq 'eval when-list)
1394 (expand-sequence #'(e1 e2 ...) r w s mod)
1396 ((define-form define-syntax-form define-syntax-parameter-form)
1397 (syntax-violation #f "definition in expression context, where definitions are not allowed,"
1398 (source-wrap form w s mod)))
1400 (syntax-violation #f "reference to pattern variable outside syntax form"
1401 (source-wrap e w s mod)))
1402 ((displaced-lexical)
1403 (syntax-violation #f "reference to identifier outside its scope"
1404 (source-wrap e w s mod)))
1405 (else (syntax-violation #f "unexpected syntax"
1406 (source-wrap e w s mod))))))
1409 (lambda (x e r w s mod)
1413 (map (lambda (e) (expand e r w mod)) #'(e1 ...)))))))
1415 ;; (What follows is my interpretation of what's going on here -- Andy)
1417 ;; A macro takes an expression, a tree, the leaves of which are identifiers
1418 ;; and datums. Identifiers are symbols along with a wrap and a module. For
1419 ;; efficiency, subtrees that share wraps and modules may be grouped as one
1422 ;; Going into the expansion, the expression is given an anti-mark, which
1423 ;; logically propagates to all leaves. Then, in the new expression returned
1424 ;; from the transfomer, if we see an expression with an anti-mark, we know it
1425 ;; pertains to the original expression; conversely, expressions without the
1426 ;; anti-mark are known to be introduced by the transformer.
1428 ;; OK, good until now. We know this algorithm does lexical scoping
1429 ;; appropriately because it's widely known in the literature, and psyntax is
1430 ;; widely used. But what about modules? Here we're on our own. What we do is
1431 ;; to mark the module of expressions produced by a macro as pertaining to the
1432 ;; module that was current when the macro was defined -- that is, free
1433 ;; identifiers introduced by a macro are scoped in the macro's module, not in
1434 ;; the expansion's module. Seems to work well.
1436 ;; The only wrinkle is when we want a macro to expand to code in another
1437 ;; module, as is the case for the r6rs `library' form -- the body expressions
1438 ;; should be scoped relative the the new module, the one defined by the macro.
1439 ;; For that, use `(@@ mod-name body)'.
1441 ;; Part of the macro output will be from the site of the macro use and part
1442 ;; from the macro definition. We allow source information from the macro use
1443 ;; to pass through, but we annotate the parts coming from the macro with the
1444 ;; source location information corresponding to the macro use. It would be
1445 ;; really nice if we could also annotate introduced expressions with the
1446 ;; locations corresponding to the macro definition, but that is not yet
1448 (define expand-macro
1449 (lambda (p e r w s rib mod)
1450 (define rebuild-macro-output
1454 (cons (rebuild-macro-output (car x) m)
1455 (rebuild-macro-output (cdr x) m))
1458 (let ((w (syntax-object-wrap x)))
1459 (let ((ms (wrap-marks w)) (ss (wrap-subst w)))
1460 (if (and (pair? ms) (eq? (car ms) the-anti-mark))
1461 ;; output is from original text
1463 (syntax-object-expression x)
1464 (make-wrap (cdr ms) (if rib (cons rib (cdr ss)) (cdr ss)))
1465 (syntax-object-module x))
1466 ;; output introduced by macro
1468 (decorate-source (syntax-object-expression x) s)
1469 (make-wrap (cons m ms)
1471 (cons rib (cons 'shift ss))
1473 (syntax-object-module x))))))
1476 (let* ((n (vector-length x))
1477 (v (decorate-source (make-vector n) s)))
1478 (do ((i 0 (fx+ i 1)))
1481 (rebuild-macro-output (vector-ref x i) m)))))
1483 (syntax-violation #f "encountered raw symbol in macro output"
1484 (source-wrap e w (wrap-subst w) mod) x))
1485 (else (decorate-source x s)))))
1486 (with-fluids ((transformer-environment
1487 (lambda (k) (k e r w s rib mod))))
1488 (rebuild-macro-output (p (source-wrap e (anti-mark w) s mod))
1492 ;; In processing the forms of the body, we create a new, empty wrap.
1493 ;; This wrap is augmented (destructively) each time we discover that
1494 ;; the next form is a definition. This is done:
1496 ;; (1) to allow the first nondefinition form to be a call to
1497 ;; one of the defined ids even if the id previously denoted a
1498 ;; definition keyword or keyword for a macro expanding into a
1500 ;; (2) to prevent subsequent definition forms (but unfortunately
1501 ;; not earlier ones) and the first nondefinition form from
1502 ;; confusing one of the bound identifiers for an auxiliary
1504 ;; (3) so that we do not need to restart the expansion of the
1505 ;; first nondefinition form, which is problematic anyway
1506 ;; since it might be the first element of a begin that we
1507 ;; have just spliced into the body (meaning if we restarted,
1508 ;; we'd really need to restart with the begin or the macro
1509 ;; call that expanded into the begin, and we'd have to give
1510 ;; up allowing (begin <defn>+ <expr>+), which is itself
1511 ;; problematic since we don't know if a begin contains only
1512 ;; definitions until we've expanded it).
1514 ;; Before processing the body, we also create a new environment
1515 ;; containing a placeholder for the bindings we will add later and
1516 ;; associate this environment with each form. In processing a
1517 ;; let-syntax or letrec-syntax, the associated environment may be
1518 ;; augmented with local keyword bindings, so the environment may
1519 ;; be different for different forms in the body. Once we have
1520 ;; gathered up all of the definitions, we evaluate the transformer
1521 ;; expressions and splice into r at the placeholder the new variable
1522 ;; and keyword bindings. This allows let-syntax or letrec-syntax
1523 ;; forms local to a portion or all of the body to shadow the
1524 ;; definition bindings.
1526 ;; Subforms of a begin, let-syntax, or letrec-syntax are spliced
1529 ;; outer-form is fully wrapped w/source
1530 (lambda (body outer-form r w mod)
1531 (let* ((r (cons '("placeholder" . (placeholder)) r))
1532 (ribcage (make-empty-ribcage))
1533 (w (make-wrap (wrap-marks w) (cons ribcage (wrap-subst w)))))
1534 (let parse ((body (map (lambda (x) (cons r (wrap x w mod))) body))
1535 (ids '()) (labels '())
1536 (var-ids '()) (vars '()) (vals '()) (bindings '()))
1538 (syntax-violation #f "no expressions in body" outer-form)
1539 (let ((e (cdar body)) (er (caar body)))
1541 (lambda () (syntax-type e er empty-wrap (source-annotation er) ribcage mod #f))
1542 (lambda (type value form e w s mod)
1545 (let ((id (wrap value w mod)) (label (gen-label)))
1546 (let ((var (gen-var id)))
1547 (extend-ribcage! ribcage id label)
1549 (cons id ids) (cons label labels)
1551 (cons var vars) (cons (cons er (wrap e w mod)) vals)
1552 (cons (make-binding 'lexical var) bindings)))))
1553 ((define-syntax-form define-syntax-parameter-form)
1554 (let ((id (wrap value w mod)) (label (gen-label)))
1555 (extend-ribcage! ribcage id label)
1557 (cons id ids) (cons label labels)
1560 (if (eq? type 'define-syntax-parameter-form)
1563 (cons er (wrap e w mod)))
1568 (parse (let f ((forms #'(e1 ...)))
1571 (cons (cons er (wrap (car forms) w mod))
1573 ids labels var-ids vars vals bindings))))
1574 ((local-syntax-form)
1575 (expand-local-syntax value e er w s mod
1576 (lambda (forms er w s mod)
1577 (parse (let f ((forms forms))
1580 (cons (cons er (wrap (car forms) w mod))
1582 ids labels var-ids vars vals bindings))))
1583 (else ; found a non-definition
1585 (build-sequence no-source
1587 (expand (cdr x) (car x) empty-wrap mod))
1588 (cons (cons er (source-wrap e w s mod))
1591 (if (not (valid-bound-ids? ids))
1593 #f "invalid or duplicate identifier in definition"
1595 (let loop ((bs bindings) (er-cache #f) (r-cache #f))
1596 (if (not (null? bs))
1597 (let* ((b (car bs)))
1598 (if (memq (car b) '(macro syntax-parameter))
1599 (let* ((er (cadr b))
1601 (if (eq? er er-cache)
1603 (macros-only-env er))))
1605 (eval-local-transformer
1606 (expand (cddr b) r-cache empty-wrap mod)
1608 (if (eq? (car b) 'syntax-parameter)
1609 (set-cdr! b (list (cdr b))))
1610 (loop (cdr bs) er r-cache))
1611 (loop (cdr bs) er-cache r-cache)))))
1612 (set-cdr! r (extend-env labels bindings (cdr r)))
1613 (build-letrec no-source #t
1614 (reverse (map syntax->datum var-ids))
1617 (expand (cdr x) (car x) empty-wrap mod))
1619 (build-sequence no-source
1621 (expand (cdr x) (car x) empty-wrap mod))
1622 (cons (cons er (source-wrap e w s mod))
1623 (cdr body)))))))))))))))))
1625 (define expand-local-syntax
1626 (lambda (rec? e r w s mod k)
1628 ((_ ((id val) ...) e1 e2 ...)
1629 (let ((ids #'(id ...)))
1630 (if (not (valid-bound-ids? ids))
1631 (syntax-violation #f "duplicate bound keyword" e)
1632 (let ((labels (gen-labels ids)))
1633 (let ((new-w (make-binding-wrap ids labels w)))
1637 (let ((w (if rec? new-w w))
1638 (trans-r (macros-only-env r)))
1640 (make-binding 'macro
1641 (eval-local-transformer
1642 (expand x trans-r w mod)
1649 (_ (syntax-violation #f "bad local syntax definition"
1650 (source-wrap e w s mod))))))
1652 (define eval-local-transformer
1653 (lambda (expanded mod)
1654 (let ((p (local-eval-hook expanded mod)))
1657 (syntax-violation #f "nonprocedure transformer" p)))))
1661 (build-void no-source)))
1665 (and (nonsymbol-id? x)
1666 (free-id=? x #'(... ...)))))
1668 (define lambda-formals
1670 (define (req args rreq)
1671 (syntax-case args ()
1673 (check (reverse rreq) #f))
1675 (req #'b (cons #'a rreq)))
1677 (check (reverse rreq) #'r))
1679 (syntax-violation 'lambda "invalid argument list" orig-args args))))
1680 (define (check req rest)
1682 ((distinct-bound-ids? (if rest (cons rest req) req))
1683 (values req #f rest #f))
1685 (syntax-violation 'lambda "duplicate identifier in argument list"
1687 (req orig-args '())))
1689 (define expand-simple-lambda
1690 (lambda (e r w s mod req rest meta body)
1691 (let* ((ids (if rest (append req (list rest)) req))
1692 (vars (map gen-var ids))
1693 (labels (gen-labels ids)))
1694 (build-simple-lambda
1696 (map syntax->datum req) (and rest (syntax->datum rest)) vars
1698 (expand-body body (source-wrap e w s mod)
1699 (extend-var-env labels vars r)
1700 (make-binding-wrap ids labels w)
1703 (define lambda*-formals
1705 (define (req args rreq)
1706 (syntax-case args ()
1708 (check (reverse rreq) '() #f '()))
1710 (req #'b (cons #'a rreq)))
1711 ((a . b) (eq? (syntax->datum #'a) #:optional)
1712 (opt #'b (reverse rreq) '()))
1713 ((a . b) (eq? (syntax->datum #'a) #:key)
1714 (key #'b (reverse rreq) '() '()))
1715 ((a b) (eq? (syntax->datum #'a) #:rest)
1716 (rest #'b (reverse rreq) '() '()))
1718 (rest #'r (reverse rreq) '() '()))
1720 (syntax-violation 'lambda* "invalid argument list" orig-args args))))
1721 (define (opt args req ropt)
1722 (syntax-case args ()
1724 (check req (reverse ropt) #f '()))
1726 (opt #'b req (cons #'(a #f) ropt)))
1727 (((a init) . b) (id? #'a)
1728 (opt #'b req (cons #'(a init) ropt)))
1729 ((a . b) (eq? (syntax->datum #'a) #:key)
1730 (key #'b req (reverse ropt) '()))
1731 ((a b) (eq? (syntax->datum #'a) #:rest)
1732 (rest #'b req (reverse ropt) '()))
1734 (rest #'r req (reverse ropt) '()))
1736 (syntax-violation 'lambda* "invalid optional argument list"
1738 (define (key args req opt rkey)
1739 (syntax-case args ()
1741 (check req opt #f (cons #f (reverse rkey))))
1743 (with-syntax ((k (symbol->keyword (syntax->datum #'a))))
1744 (key #'b req opt (cons #'(k a #f) rkey))))
1745 (((a init) . b) (id? #'a)
1746 (with-syntax ((k (symbol->keyword (syntax->datum #'a))))
1747 (key #'b req opt (cons #'(k a init) rkey))))
1748 (((a init k) . b) (and (id? #'a)
1749 (keyword? (syntax->datum #'k)))
1750 (key #'b req opt (cons #'(k a init) rkey)))
1751 ((aok) (eq? (syntax->datum #'aok) #:allow-other-keys)
1752 (check req opt #f (cons #t (reverse rkey))))
1753 ((aok a b) (and (eq? (syntax->datum #'aok) #:allow-other-keys)
1754 (eq? (syntax->datum #'a) #:rest))
1755 (rest #'b req opt (cons #t (reverse rkey))))
1756 ((aok . r) (and (eq? (syntax->datum #'aok) #:allow-other-keys)
1758 (rest #'r req opt (cons #t (reverse rkey))))
1759 ((a b) (eq? (syntax->datum #'a) #:rest)
1760 (rest #'b req opt (cons #f (reverse rkey))))
1762 (rest #'r req opt (cons #f (reverse rkey))))
1764 (syntax-violation 'lambda* "invalid keyword argument list"
1766 (define (rest args req opt kw)
1767 (syntax-case args ()
1769 (check req opt #'r kw))
1771 (syntax-violation 'lambda* "invalid rest argument"
1773 (define (check req opt rest kw)
1775 ((distinct-bound-ids?
1776 (append req (map car opt) (if rest (list rest) '())
1777 (if (pair? kw) (map cadr (cdr kw)) '())))
1778 (values req opt rest kw))
1780 (syntax-violation 'lambda* "duplicate identifier in argument list"
1782 (req orig-args '())))
1784 (define expand-lambda-case
1785 (lambda (e r w s mod get-formals clauses)
1786 (define (parse-req req opt rest kw body)
1787 (let ((vars (map gen-var req))
1788 (labels (gen-labels req)))
1789 (let ((r* (extend-var-env labels vars r))
1790 (w* (make-binding-wrap req labels w)))
1791 (parse-opt (map syntax->datum req)
1792 opt rest kw body (reverse vars) r* w* '() '()))))
1793 (define (parse-opt req opt rest kw body vars r* w* out inits)
1796 (syntax-case (car opt) ()
1798 (let* ((v (gen-var #'id))
1799 (l (gen-labels (list v)))
1800 (r** (extend-var-env l (list v) r*))
1801 (w** (make-binding-wrap (list #'id) l w*)))
1802 (parse-opt req (cdr opt) rest kw body (cons v vars)
1803 r** w** (cons (syntax->datum #'id) out)
1804 (cons (expand #'i r* w* mod) inits))))))
1806 (let* ((v (gen-var rest))
1807 (l (gen-labels (list v)))
1808 (r* (extend-var-env l (list v) r*))
1809 (w* (make-binding-wrap (list rest) l w*)))
1810 (parse-kw req (if (pair? out) (reverse out) #f)
1811 (syntax->datum rest)
1812 (if (pair? kw) (cdr kw) kw)
1813 body (cons v vars) r* w*
1814 (if (pair? kw) (car kw) #f)
1817 (parse-kw req (if (pair? out) (reverse out) #f) #f
1818 (if (pair? kw) (cdr kw) kw)
1820 (if (pair? kw) (car kw) #f)
1822 (define (parse-kw req opt rest kw body vars r* w* aok out inits)
1825 (syntax-case (car kw) ()
1827 (let* ((v (gen-var #'id))
1828 (l (gen-labels (list v)))
1829 (r** (extend-var-env l (list v) r*))
1830 (w** (make-binding-wrap (list #'id) l w*)))
1831 (parse-kw req opt rest (cdr kw) body (cons v vars)
1833 (cons (list (syntax->datum #'k)
1834 (syntax->datum #'id)
1837 (cons (expand #'i r* w* mod) inits))))))
1839 (parse-body req opt rest
1840 (if (or aok (pair? out)) (cons aok (reverse out)) #f)
1841 body (reverse vars) r* w* (reverse inits) '()))))
1842 (define (parse-body req opt rest kw body vars r* w* inits meta)
1843 (syntax-case body ()
1844 ((docstring e1 e2 ...) (string? (syntax->datum #'docstring))
1845 (parse-body req opt rest kw #'(e1 e2 ...) vars r* w* inits
1848 . ,(syntax->datum #'docstring))))))
1849 ((#((k . v) ...) e1 e2 ...)
1850 (parse-body req opt rest kw #'(e1 e2 ...) vars r* w* inits
1851 (append meta (syntax->datum #'((k . v) ...)))))
1853 (values meta req opt rest kw inits vars
1854 (expand-body #'(e1 e2 ...) (source-wrap e w s mod)
1857 (syntax-case clauses ()
1858 (() (values '() #f))
1859 (((args e1 e2 ...) (args* e1* e2* ...) ...)
1860 (call-with-values (lambda () (get-formals #'args))
1861 (lambda (req opt rest kw)
1862 (call-with-values (lambda ()
1863 (parse-req req opt rest kw #'(e1 e2 ...)))
1864 (lambda (meta req opt rest kw inits vars body)
1867 (expand-lambda-case e r w s mod get-formals
1868 #'((args* e1* e2* ...) ...)))
1869 (lambda (meta* else*)
1872 (build-lambda-case s req opt rest kw inits vars
1873 body else*))))))))))))
1877 ;; strips syntax-objects down to top-wrap
1879 ;; since only the head of a list is annotated by the reader, not each pair
1880 ;; in the spine, we also check for pairs whose cars are annotated in case
1881 ;; we've been passed the cdr of an annotated list
1890 (strip (syntax-object-expression x) (syntax-object-wrap x)))
1892 (let ((a (f (car x))) (d (f (cdr x))))
1893 (if (and (eq? a (car x)) (eq? d (cdr x)))
1897 (let ((old (vector->list x)))
1898 (let ((new (map f old)))
1899 ;; inlined and-map with two args
1900 (let lp ((l1 old) (l2 new))
1903 (if (eq? (car l1) (car l2))
1904 (lp (cdr l1) (cdr l2))
1905 (list->vector new)))))))
1908 ;; lexical variables
1912 (let ((id (if (syntax-object? id) (syntax-object-expression id) id)))
1913 (build-lexical-var no-source id))))
1915 ;; appears to return a reversed list
1916 (define lambda-var-list
1918 (let lvl ((vars vars) (ls '()) (w empty-wrap))
1920 ((pair? vars) (lvl (cdr vars) (cons (wrap (car vars) w #f) ls) w))
1921 ((id? vars) (cons (wrap vars w #f) ls))
1923 ((syntax-object? vars)
1924 (lvl (syntax-object-expression vars)
1926 (join-wraps w (syntax-object-wrap vars))))
1927 ;; include anything else to be caught by subsequent error
1929 (else (cons vars ls))))))
1931 ;; core transformers
1933 (global-extend 'local-syntax 'letrec-syntax #t)
1934 (global-extend 'local-syntax 'let-syntax #f)
1937 'core 'syntax-parameterize
1938 (lambda (e r w s mod)
1940 ((_ ((var val) ...) e1 e2 ...)
1941 (valid-bound-ids? #'(var ...))
1945 (lambda () (resolve-identifier x w r mod #f))
1946 (lambda (type value mod)
1948 ((displaced-lexical)
1949 (syntax-violation 'syntax-parameterize
1950 "identifier out of context"
1952 (source-wrap x w s mod)))
1956 (syntax-violation 'syntax-parameterize
1957 "invalid syntax parameter"
1959 (source-wrap x w s mod)))))))
1962 (let ((trans-r (macros-only-env r)))
1966 (eval-local-transformer (expand x trans-r w mod) mod)))
1968 (expand-body #'(e1 e2 ...)
1969 (source-wrap e w s mod)
1970 (extend-env names bindings r)
1973 (_ (syntax-violation 'syntax-parameterize "bad syntax"
1974 (source-wrap e w s mod))))))
1976 (global-extend 'core 'quote
1977 (lambda (e r w s mod)
1979 ((_ e) (build-data s (strip #'e w)))
1980 (_ (syntax-violation 'quote "bad syntax"
1981 (source-wrap e w s mod))))))
1987 (lambda (src e r maps ellipsis? mod)
1989 (call-with-values (lambda ()
1990 (resolve-identifier e empty-wrap r mod #f))
1991 (lambda (type value mod)
1995 (lambda () (gen-ref src (car value) (cdr value) maps))
1997 (values `(ref ,var) maps))))
2000 (syntax-violation 'syntax "misplaced ellipsis" src)
2001 (values `(quote ,e) maps))))))
2005 (gen-syntax src #'e r maps (lambda (x) #f) mod))
2007 ;; this could be about a dozen lines of code, except that we
2008 ;; choose to handle #'(x ... ...) forms
2014 (gen-syntax src #'x r
2015 (cons '() maps) ellipsis? mod))
2017 (if (null? (car maps))
2018 (syntax-violation 'syntax "extra ellipsis"
2020 (values (gen-map x (car maps))
2028 (lambda () (k (cons '() maps)))
2030 (if (null? (car maps))
2031 (syntax-violation 'syntax "extra ellipsis" src)
2032 (values (gen-mappend x (car maps))
2034 (_ (call-with-values
2035 (lambda () (gen-syntax src y r maps ellipsis? mod))
2038 (lambda () (k maps))
2040 (values (gen-append x y) maps)))))))))
2043 (lambda () (gen-syntax src #'x r maps ellipsis? mod))
2046 (lambda () (gen-syntax src #'y r maps ellipsis? mod))
2047 (lambda (y maps) (values (gen-cons x y) maps))))))
2051 (gen-syntax src #'(e1 e2 ...) r maps ellipsis? mod))
2052 (lambda (e maps) (values (gen-vector e) maps))))
2053 (_ (values `(quote ,e) maps))))))
2056 (lambda (src var level maps)
2060 (syntax-violation 'syntax "missing ellipsis" src)
2062 (lambda () (gen-ref src var (fx- level 1) (cdr maps)))
2063 (lambda (outer-var outer-maps)
2064 (let ((b (assq outer-var (car maps))))
2066 (values (cdr b) maps)
2067 (let ((inner-var (gen-var 'tmp)))
2069 (cons (cons (cons outer-var inner-var)
2071 outer-maps)))))))))))
2075 `(apply (primitive append) ,(gen-map e map-env))))
2079 (let ((formals (map cdr map-env))
2080 (actuals (map (lambda (x) `(ref ,(car x))) map-env)))
2083 ;; identity map equivalence:
2084 ;; (map (lambda (x) x) y) == y
2087 (lambda (x) (and (eq? (car x) 'ref) (memq (cadr x) formals)))
2089 ;; eta map equivalence:
2090 ;; (map (lambda (x ...) (f x ...)) y ...) == (map f y ...)
2091 `(map (primitive ,(car e))
2092 ,@(map (let ((r (map cons formals actuals)))
2093 (lambda (x) (cdr (assq (cadr x) r))))
2095 (else `(map (lambda ,formals ,e) ,@actuals))))))
2101 (if (eq? (car x) 'quote)
2102 `(quote (,(cadr x) . ,(cadr y)))
2103 (if (eq? (cadr y) '())
2106 ((list) `(list ,x ,@(cdr y)))
2107 (else `(cons ,x ,y)))))
2111 (if (equal? y '(quote ()))
2118 ((eq? (car x) 'list) `(vector ,@(cdr x)))
2119 ((eq? (car x) 'quote) `(quote #(,@(cadr x))))
2120 (else `(list->vector ,x)))))
2126 ((ref) (build-lexical-reference 'value no-source (cadr x) (cadr x)))
2127 ((primitive) (build-primref no-source (cadr x)))
2128 ((quote) (build-data no-source (cadr x)))
2130 (if (list? (cadr x))
2131 (build-simple-lambda no-source (cadr x) #f (cadr x) '() (regen (caddr x)))
2132 (error "how did we get here" x)))
2133 (else (build-primcall no-source (car x) (map regen (cdr x)))))))
2135 (lambda (e r w s mod)
2136 (let ((e (source-wrap e w s mod)))
2140 (lambda () (gen-syntax e #'x r '() ellipsis? mod))
2141 (lambda (e maps) (regen e))))
2142 (_ (syntax-violation 'syntax "bad `syntax' form" e)))))))
2144 (global-extend 'core 'lambda
2145 (lambda (e r w s mod)
2148 (call-with-values (lambda () (lambda-formals #'args))
2149 (lambda (req opt rest kw)
2150 (let lp ((body #'(e1 e2 ...)) (meta '()))
2151 (syntax-case body ()
2152 ((docstring e1 e2 ...) (string? (syntax->datum #'docstring))
2156 . ,(syntax->datum #'docstring))))))
2157 ((#((k . v) ...) e1 e2 ...)
2159 (append meta (syntax->datum #'((k . v) ...)))))
2160 (_ (expand-simple-lambda e r w s mod req rest meta body)))))))
2161 (_ (syntax-violation 'lambda "bad lambda" e)))))
2163 (global-extend 'core 'lambda*
2164 (lambda (e r w s mod)
2169 (expand-lambda-case e r w s mod
2170 lambda*-formals #'((args e1 e2 ...))))
2171 (lambda (meta lcase)
2172 (build-case-lambda s meta lcase))))
2173 (_ (syntax-violation 'lambda "bad lambda*" e)))))
2175 (global-extend 'core 'case-lambda
2176 (lambda (e r w s mod)
2178 ((_ (args e1 e2 ...) (args* e1* e2* ...) ...)
2181 (expand-lambda-case e r w s mod
2183 #'((args e1 e2 ...) (args* e1* e2* ...) ...)))
2184 (lambda (meta lcase)
2185 (build-case-lambda s meta lcase))))
2186 (_ (syntax-violation 'case-lambda "bad case-lambda" e)))))
2188 (global-extend 'core 'case-lambda*
2189 (lambda (e r w s mod)
2191 ((_ (args e1 e2 ...) (args* e1* e2* ...) ...)
2194 (expand-lambda-case e r w s mod
2196 #'((args e1 e2 ...) (args* e1* e2* ...) ...)))
2197 (lambda (meta lcase)
2198 (build-case-lambda s meta lcase))))
2199 (_ (syntax-violation 'case-lambda "bad case-lambda*" e)))))
2201 (global-extend 'core 'let
2203 (define (expand-let e r w s mod constructor ids vals exps)
2204 (if (not (valid-bound-ids? ids))
2205 (syntax-violation 'let "duplicate bound variable" e)
2206 (let ((labels (gen-labels ids))
2207 (new-vars (map gen-var ids)))
2208 (let ((nw (make-binding-wrap ids labels w))
2209 (nr (extend-var-env labels new-vars r)))
2211 (map syntax->datum ids)
2213 (map (lambda (x) (expand x r w mod)) vals)
2214 (expand-body exps (source-wrap e nw s mod)
2216 (lambda (e r w s mod)
2218 ((_ ((id val) ...) e1 e2 ...)
2219 (and-map id? #'(id ...))
2220 (expand-let e r w s mod
2225 ((_ f ((id val) ...) e1 e2 ...)
2226 (and (id? #'f) (and-map id? #'(id ...)))
2227 (expand-let e r w s mod
2232 (_ (syntax-violation 'let "bad let" (source-wrap e w s mod)))))))
2235 (global-extend 'core 'letrec
2236 (lambda (e r w s mod)
2238 ((_ ((id val) ...) e1 e2 ...)
2239 (and-map id? #'(id ...))
2240 (let ((ids #'(id ...)))
2241 (if (not (valid-bound-ids? ids))
2242 (syntax-violation 'letrec "duplicate bound variable" e)
2243 (let ((labels (gen-labels ids))
2244 (new-vars (map gen-var ids)))
2245 (let ((w (make-binding-wrap ids labels w))
2246 (r (extend-var-env labels new-vars r)))
2248 (map syntax->datum ids)
2250 (map (lambda (x) (expand x r w mod)) #'(val ...))
2251 (expand-body #'(e1 e2 ...)
2252 (source-wrap e w s mod) r w mod)))))))
2253 (_ (syntax-violation 'letrec "bad letrec" (source-wrap e w s mod))))))
2256 (global-extend 'core 'letrec*
2257 (lambda (e r w s mod)
2259 ((_ ((id val) ...) e1 e2 ...)
2260 (and-map id? #'(id ...))
2261 (let ((ids #'(id ...)))
2262 (if (not (valid-bound-ids? ids))
2263 (syntax-violation 'letrec* "duplicate bound variable" e)
2264 (let ((labels (gen-labels ids))
2265 (new-vars (map gen-var ids)))
2266 (let ((w (make-binding-wrap ids labels w))
2267 (r (extend-var-env labels new-vars r)))
2269 (map syntax->datum ids)
2271 (map (lambda (x) (expand x r w mod)) #'(val ...))
2272 (expand-body #'(e1 e2 ...)
2273 (source-wrap e w s mod) r w mod)))))))
2274 (_ (syntax-violation 'letrec* "bad letrec*" (source-wrap e w s mod))))))
2279 (lambda (e r w s mod)
2284 (lambda () (resolve-identifier #'id w r mod #t))
2285 (lambda (type value id-mod)
2288 (build-lexical-assignment s (syntax->datum #'id) value
2289 (expand #'val r w mod)))
2291 (build-global-assignment s value (expand #'val r w mod) id-mod))
2293 (if (procedure-property value 'variable-transformer)
2294 ;; As syntax-type does, call expand-macro with
2295 ;; the mod of the expression. Hmm.
2296 (expand (expand-macro value e r w s #f mod) r empty-wrap mod)
2297 (syntax-violation 'set! "not a variable transformer"
2299 (wrap #'id w id-mod))))
2300 ((displaced-lexical)
2301 (syntax-violation 'set! "identifier out of context"
2304 (syntax-violation 'set! "bad set!" (source-wrap e w s mod)))))))
2305 ((_ (head tail ...) val)
2307 (lambda () (syntax-type #'head r empty-wrap no-source #f mod #t))
2308 (lambda (type value ee* ee ww ss modmod)
2311 (let ((val (expand #'val r w mod)))
2312 (call-with-values (lambda () (value #'(head tail ...) r w))
2313 (lambda (e r w s* mod)
2316 (build-global-assignment s (syntax->datum #'e)
2320 (expand #'(setter head) r w mod)
2321 (map (lambda (e) (expand e r w mod))
2322 #'(tail ... val))))))))
2323 (_ (syntax-violation 'set! "bad set!" (source-wrap e w s mod))))))
2325 (global-extend 'module-ref '@
2329 (and (and-map id? #'(mod ...)) (id? #'id))
2330 (values (syntax->datum #'id) r w #f
2332 #'(public mod ...)))))))
2334 (global-extend 'module-ref '@@
2339 (cons (remodulate (car x) mod)
2340 (remodulate (cdr x) mod)))
2343 (remodulate (syntax-object-expression x) mod)
2344 (syntax-object-wrap x)
2345 ;; hither the remodulation
2348 (let* ((n (vector-length x)) (v (make-vector n)))
2349 (do ((i 0 (fx+ i 1)))
2351 (vector-set! v i (remodulate (vector-ref x i) mod)))))
2355 (and-map id? #'(mod ...))
2356 (let ((mod (syntax->datum #'(private mod ...))))
2357 (values (remodulate #'exp mod)
2358 r w (source-annotation #'exp)
2361 (global-extend 'core 'if
2362 (lambda (e r w s mod)
2367 (expand #'test r w mod)
2368 (expand #'then r w mod)
2369 (build-void no-source)))
2373 (expand #'test r w mod)
2374 (expand #'then r w mod)
2375 (expand #'else r w mod))))))
2377 (global-extend 'core 'with-fluids
2378 (lambda (e r w s mod)
2380 ((_ ((fluid val) ...) b b* ...)
2383 (map (lambda (x) (expand x r w mod)) #'(fluid ...))
2384 (map (lambda (x) (expand x r w mod)) #'(val ...))
2385 (expand-body #'(b b* ...)
2386 (source-wrap e w s mod) r w mod))))))
2388 (global-extend 'begin 'begin '())
2390 (global-extend 'define 'define '())
2392 (global-extend 'define-syntax 'define-syntax '())
2393 (global-extend 'define-syntax-parameter 'define-syntax-parameter '())
2395 (global-extend 'eval-when 'eval-when '())
2397 (global-extend 'core 'syntax-case
2399 (define convert-pattern
2400 ;; accepts pattern & keys
2401 ;; returns $sc-dispatch pattern & ids
2402 (lambda (pattern keys)
2405 (if (not (pair? p*))
2408 (lambda () (cvt* (cdr p*) n ids))
2411 (lambda () (cvt (car p*) n ids))
2413 (values (cons x y) ids))))))))
2415 (define (v-reverse x)
2416 (let loop ((r '()) (x x))
2419 (loop (cons (car x) r) (cdr x)))))
2425 ((bound-id-member? p keys)
2426 (values (vector 'free-id p) ids))
2430 (values 'any (cons (cons p n) ids))))
2433 (ellipsis? (syntax dots))
2435 (lambda () (cvt (syntax x) (fx+ n 1) ids))
2437 (values (if (eq? p 'any) 'each-any (vector 'each p))
2440 (ellipsis? (syntax dots))
2442 (lambda () (cvt* (syntax ys) n ids))
2445 (lambda () (cvt (syntax x) (+ n 1) ids))
2448 (lambda () (v-reverse ys))
2450 (values `#(each+ ,x ,ys ,e)
2454 (lambda () (cvt (syntax y) n ids))
2457 (lambda () (cvt (syntax x) n ids))
2459 (values (cons x y) ids))))))
2460 (() (values '() ids))
2463 (lambda () (cvt (syntax (x ...)) n ids))
2464 (lambda (p ids) (values (vector 'vector p) ids))))
2465 (x (values (vector 'atom (strip p empty-wrap)) ids))))))
2466 (cvt pattern 0 '())))
2468 (define build-dispatch-call
2469 (lambda (pvars exp y r mod)
2470 (let ((ids (map car pvars)) (levels (map cdr pvars)))
2471 (let ((labels (gen-labels ids)) (new-vars (map gen-var ids)))
2475 (list (build-simple-lambda no-source (map syntax->datum ids) #f new-vars '()
2479 (map (lambda (var level)
2480 (make-binding 'syntax `(,var . ,level)))
2484 (make-binding-wrap ids labels empty-wrap)
2489 (lambda (x keys clauses r pat fender exp mod)
2491 (lambda () (convert-pattern pat keys))
2494 ((not (distinct-bound-ids? (map car pvars)))
2495 (syntax-violation 'syntax-case "duplicate pattern variable" pat))
2496 ((not (and-map (lambda (x) (not (ellipsis? (car x)))) pvars))
2497 (syntax-violation 'syntax-case "misplaced ellipsis" pat))
2499 (let ((y (gen-var 'tmp)))
2500 ;; fat finger binding and references to temp variable y
2501 (build-call no-source
2502 (build-simple-lambda no-source (list 'tmp) #f (list y) '()
2503 (let ((y (build-lexical-reference 'value no-source
2505 (build-conditional no-source
2506 (syntax-case fender ()
2508 (_ (build-conditional no-source
2510 (build-dispatch-call pvars fender y r mod)
2511 (build-data no-source #f))))
2512 (build-dispatch-call pvars exp y r mod)
2513 (gen-syntax-case x keys clauses r mod))))
2514 (list (if (eq? p 'any)
2515 (build-primcall no-source 'list (list x))
2516 (build-primcall no-source '$sc-dispatch
2517 (list x (build-data no-source p)))))))))))))
2519 (define gen-syntax-case
2520 (lambda (x keys clauses r mod)
2522 (build-primcall no-source 'syntax-violation
2523 (list (build-data no-source #f)
2524 (build-data no-source
2525 "source expression failed to match any pattern")
2527 (syntax-case (car clauses) ()
2529 (if (and (id? #'pat)
2530 (and-map (lambda (x) (not (free-id=? #'pat x)))
2531 (cons #'(... ...) keys)))
2532 (if (free-id=? #'pad #'_)
2533 (expand #'exp r empty-wrap mod)
2534 (let ((labels (list (gen-label)))
2535 (var (gen-var #'pat)))
2536 (build-call no-source
2537 (build-simple-lambda
2538 no-source (list (syntax->datum #'pat)) #f (list var)
2542 (list (make-binding 'syntax `(,var . 0)))
2544 (make-binding-wrap #'(pat)
2548 (gen-clause x keys (cdr clauses) r
2549 #'pat #t #'exp mod)))
2551 (gen-clause x keys (cdr clauses) r
2552 #'pat #'fender #'exp mod))
2553 (_ (syntax-violation 'syntax-case "invalid clause"
2556 (lambda (e r w s mod)
2557 (let ((e (source-wrap e w s mod)))
2559 ((_ val (key ...) m ...)
2560 (if (and-map (lambda (x) (and (id? x) (not (ellipsis? x))))
2562 (let ((x (gen-var 'tmp)))
2563 ;; fat finger binding and references to temp variable x
2565 (build-simple-lambda no-source (list 'tmp) #f (list x) '()
2566 (gen-syntax-case (build-lexical-reference 'value no-source
2568 #'(key ...) #'(m ...)
2571 (list (expand #'val r empty-wrap mod))))
2572 (syntax-violation 'syntax-case "invalid literals list" e))))))))
2574 ;; The portable macroexpand seeds expand-top's mode m with 'e (for
2575 ;; evaluating) and esew (which stands for "eval syntax expanders
2576 ;; when") with '(eval). In Chez Scheme, m is set to 'c instead of e
2577 ;; if we are compiling a file, and esew is set to
2578 ;; (eval-syntactic-expanders-when), which defaults to the list
2579 ;; '(compile load eval). This means that, by default, top-level
2580 ;; syntactic definitions are evaluated immediately after they are
2581 ;; expanded, and the expanded definitions are also residualized into
2582 ;; the object file if we are compiling a file.
2584 (lambda* (x #:optional (m 'e) (esew '(eval)))
2585 (expand-top-sequence (list x) null-env top-wrap #f m esew
2586 (cons 'hygiene (module-name (current-module))))))
2594 (make-syntax-object datum (syntax-object-wrap id)
2595 (syntax-object-module id))))
2598 ;; accepts any object, since syntax objects may consist partially
2599 ;; or entirely of unwrapped, nonsymbolic data
2601 (strip x empty-wrap)))
2604 (lambda (x) (source-annotation x)))
2606 (set! generate-temporaries
2608 (arg-check list? ls 'generate-temporaries)
2609 (let ((mod (cons 'hygiene (module-name (current-module)))))
2610 (map (lambda (x) (wrap (gensym "t-") top-wrap mod)) ls))))
2612 (set! free-identifier=?
2614 (arg-check nonsymbol-id? x 'free-identifier=?)
2615 (arg-check nonsymbol-id? y 'free-identifier=?)
2618 (set! bound-identifier=?
2620 (arg-check nonsymbol-id? x 'bound-identifier=?)
2621 (arg-check nonsymbol-id? y 'bound-identifier=?)
2624 (set! syntax-violation
2625 (lambda* (who message form #:optional subform)
2626 (arg-check (lambda (x) (or (not x) (string? x) (symbol? x)))
2627 who 'syntax-violation)
2628 (arg-check string? message 'syntax-violation)
2629 (throw 'syntax-error who message
2630 (or (source-annotation subform)
2631 (source-annotation form))
2632 (strip form empty-wrap)
2633 (and subform (strip subform empty-wrap)))))
2636 (define (syntax-module id)
2637 (arg-check nonsymbol-id? id 'syntax-module)
2638 (cdr (syntax-object-module id)))
2640 (define (syntax-local-binding id)
2641 (arg-check nonsymbol-id? id 'syntax-local-binding)
2642 (with-transformer-environment
2643 (lambda (e r w s rib mod)
2644 (define (strip-anti-mark w)
2645 (let ((ms (wrap-marks w)) (s (wrap-subst w)))
2646 (if (and (pair? ms) (eq? (car ms) the-anti-mark))
2647 ;; output is from original text
2648 (make-wrap (cdr ms) (if rib (cons rib (cdr s)) (cdr s)))
2649 ;; output introduced by macro
2650 (make-wrap ms (if rib (cons rib s) s)))))
2651 (call-with-values (lambda ()
2653 (syntax-object-expression id)
2654 (strip-anti-mark (syntax-object-wrap id))
2656 (syntax-object-module id)
2657 ;; FIXME: come up with a better policy for
2658 ;; resolve-syntax-parameters
2660 (lambda (type value mod)
2662 ((lexical) (values 'lexical value))
2663 ((macro) (values 'macro value))
2664 ((syntax) (values 'pattern-variable value))
2665 ((displaced-lexical) (values 'displaced-lexical #f))
2666 ((global) (values 'global (cons value (cdr mod))))
2667 (else (values 'other #f))))))))
2669 (define (syntax-locally-bound-identifiers id)
2670 (arg-check nonsymbol-id? id 'syntax-locally-bound-identifiers)
2671 (locally-bound-identifiers (syntax-object-wrap id)
2672 (syntax-object-module id)))
2674 ;; Using define! instead of set! to avoid warnings at
2675 ;; compile-time, after the variables are stolen away into (system
2676 ;; syntax). See the end of boot-9.scm.
2678 (define! 'syntax-module syntax-module)
2679 (define! 'syntax-local-binding syntax-local-binding)
2680 (define! 'syntax-locally-bound-identifiers syntax-locally-bound-identifiers))
2682 ;; $sc-dispatch expects an expression and a pattern. If the expression
2683 ;; matches the pattern a list of the matching expressions for each
2684 ;; "any" is returned. Otherwise, #f is returned. (This use of #f will
2685 ;; not work on r4rs implementations that violate the ieee requirement
2686 ;; that #f and () be distinct.)
2688 ;; The expression is matched with the pattern as follows:
2690 ;; pattern: matches:
2693 ;; (<pattern>1 . <pattern>2) (<pattern>1 . <pattern>2)
2695 ;; #(free-id <key>) <key> with free-identifier=?
2696 ;; #(each <pattern>) (<pattern>*)
2697 ;; #(each+ p1 (p2_1 ... p2_n) p3) (p1* (p2_n ... p2_1) . p3)
2698 ;; #(vector <pattern>) (list->vector <pattern>)
2699 ;; #(atom <object>) <object> with "equal?"
2701 ;; Vector cops out to pair under assumption that vectors are rare. If
2702 ;; not, should convert to:
2703 ;; #(vector <pattern>*) #(<pattern>*)
2711 (let ((first (match (car e) p w '() mod)))
2713 (let ((rest (match-each (cdr e) p w mod)))
2714 (and rest (cons first rest))))))
2717 (match-each (syntax-object-expression e)
2719 (join-wraps w (syntax-object-wrap e))
2720 (syntax-object-module e)))
2724 (lambda (e x-pat y-pat z-pat w r mod)
2725 (let f ((e e) (w w))
2728 (call-with-values (lambda () (f (cdr e) w))
2729 (lambda (xr* y-pat r)
2732 (let ((xr (match (car e) x-pat w '() mod)))
2734 (values (cons xr xr*) y-pat r)
2739 (match (car e) (car y-pat) w r mod)))
2740 (values #f #f #f)))))
2742 (f (syntax-object-expression e) (join-wraps w e)))
2744 (values '() y-pat (match e z-pat w r mod)))))))
2746 (define match-each-any
2750 (let ((l (match-each-any (cdr e) w mod)))
2751 (and l (cons (wrap (car e) w mod) l))))
2754 (match-each-any (syntax-object-expression e)
2755 (join-wraps w (syntax-object-wrap e))
2764 ((eq? p 'any) (cons '() r))
2765 ((pair? p) (match-empty (car p) (match-empty (cdr p) r)))
2766 ((eq? p 'each-any) (cons '() r))
2768 (case (vector-ref p 0)
2769 ((each) (match-empty (vector-ref p 1) r))
2770 ((each+) (match-empty (vector-ref p 1)
2772 (reverse (vector-ref p 2))
2773 (match-empty (vector-ref p 3) r))))
2775 ((vector) (match-empty (vector-ref p 1) r)))))))
2779 (if (null? (car r*))
2781 (cons (map car r*) (combine (map cdr r*) r)))))
2784 (lambda (e p w r mod)
2786 ((null? p) (and (null? e) r))
2788 (and (pair? e) (match (car e) (car p) w
2789 (match (cdr e) (cdr p) w r mod)
2792 (let ((l (match-each-any e w mod))) (and l (cons l r))))
2794 (case (vector-ref p 0)
2797 (match-empty (vector-ref p 1) r)
2798 (let ((l (match-each e (vector-ref p 1) w mod)))
2800 (let collect ((l l))
2803 (cons (map car l) (collect (map cdr l)))))))))
2807 (match-each+ e (vector-ref p 1) (vector-ref p 2) (vector-ref p 3) w r mod))
2808 (lambda (xr* y-pat r)
2812 (match-empty (vector-ref p 1) r)
2813 (combine xr* r))))))
2814 ((free-id) (and (id? e) (free-id=? (wrap e w mod) (vector-ref p 1)) r))
2815 ((atom) (and (equal? (vector-ref p 1) (strip e w)) r))
2818 (match (vector->list e) (vector-ref p 1) w r mod))))))))
2821 (lambda (e p w r mod)
2825 ((eq? p 'any) (cons (wrap e w mod) r))
2828 (syntax-object-expression e)
2830 (join-wraps w (syntax-object-wrap e))
2832 (syntax-object-module e)))
2833 (else (match* e p w r mod)))))
2838 ((eq? p 'any) (list e))
2841 (match* (syntax-object-expression e)
2842 p (syntax-object-wrap e) '() (syntax-object-module e)))
2843 (else (match* e p empty-wrap '() #f))))))))
2846 (define-syntax with-syntax
2850 #'(let () e1 e2 ...))
2851 ((_ ((out in)) e1 e2 ...)
2852 #'(syntax-case in ()
2853 (out (let () e1 e2 ...))))
2854 ((_ ((out in) ...) e1 e2 ...)
2855 #'(syntax-case (list in ...) ()
2856 ((out ...) (let () e1 e2 ...)))))))
2858 (define-syntax syntax-rules
2861 ((_ (k ...) ((keyword . pattern) template) ...)
2863 ;; embed patterns as procedure metadata
2864 #((macro-type . syntax-rules)
2865 (patterns pattern ...))
2866 (syntax-case x (k ...)
2867 ((_ . pattern) #'template)
2869 ((_ (k ...) docstring ((keyword . pattern) template) ...)
2870 (string? (syntax->datum #'docstring))
2872 ;; the same, but allow a docstring
2874 #((macro-type . syntax-rules)
2875 (patterns pattern ...))
2876 (syntax-case x (k ...)
2877 ((_ . pattern) #'template)
2880 (define-syntax define-syntax-rule
2883 ((_ (name . pattern) template)
2884 #'(define-syntax name
2886 ((_ . pattern) template))))
2887 ((_ (name . pattern) docstring template)
2888 (string? (syntax->datum #'docstring))
2889 #'(define-syntax name
2892 ((_ . pattern) template)))))))
2897 ((let* ((x v) ...) e1 e2 ...)
2898 (and-map identifier? #'(x ...))
2899 (let f ((bindings #'((x v) ...)))
2900 (if (null? bindings)
2901 #'(let () e1 e2 ...)
2902 (with-syntax ((body (f (cdr bindings)))
2903 (binding (car bindings)))
2904 #'(let (binding) body))))))))
2908 (syntax-case orig-x ()
2909 ((_ ((var init . step) ...) (e0 e1 ...) c ...)
2910 (with-syntax (((step ...)
2915 (_ (syntax-violation
2916 'do "bad step expression"
2920 (syntax-case #'(e1 ...) ()
2921 (() #'(let doloop ((var init) ...)
2923 (begin c ... (doloop step ...)))))
2925 #'(let doloop ((var init) ...)
2928 (begin c ... (doloop step ...)))))))))))
2930 (define-syntax quasiquote
2932 (define (quasi p lev)
2933 (syntax-case p (unquote quasiquote)
2937 (quasicons #'("quote" unquote) (quasi #'(p) (- lev 1)))))
2938 ((quasiquote p) (quasicons #'("quote" quasiquote) (quasi #'(p) (+ lev 1))))
2940 (syntax-case #'p (unquote unquote-splicing)
2943 (quasilist* #'(("value" p) ...) (quasi #'q lev))
2945 (quasicons #'("quote" unquote) (quasi #'(p ...) (- lev 1)))
2947 ((unquote-splicing p ...)
2949 (quasiappend #'(("value" p) ...) (quasi #'q lev))
2951 (quasicons #'("quote" unquote-splicing) (quasi #'(p ...) (- lev 1)))
2953 (_ (quasicons (quasi #'p lev) (quasi #'q lev)))))
2954 (#(x ...) (quasivector (vquasi #'(x ...) lev)))
2956 (define (vquasi p lev)
2959 (syntax-case #'p (unquote unquote-splicing)
2962 (quasilist* #'(("value" p) ...) (vquasi #'q lev))
2964 (quasicons #'("quote" unquote) (quasi #'(p ...) (- lev 1)))
2966 ((unquote-splicing p ...)
2968 (quasiappend #'(("value" p) ...) (vquasi #'q lev))
2971 #'("quote" unquote-splicing)
2972 (quasi #'(p ...) (- lev 1)))
2974 (_ (quasicons (quasi #'p lev) (vquasi #'q lev)))))
2975 (() #'("quote" ()))))
2976 (define (quasicons x y)
2977 (with-syntax ((x x) (y y))
2981 (("quote" dx) #'("quote" (dx . dy)))
2982 (_ (if (null? #'dy) #'("list" x) #'("list*" x y)))))
2983 (("list" . stuff) #'("list" x . stuff))
2984 (("list*" . stuff) #'("list*" x . stuff))
2985 (_ #'("list*" x y)))))
2986 (define (quasiappend x y)
2990 ((null? x) #'("quote" ()))
2991 ((null? (cdr x)) (car x))
2992 (else (with-syntax (((p ...) x)) #'("append" p ...)))))
2996 (else (with-syntax (((p ...) x) (y y)) #'("append" p ... y)))))))
2997 (define (quasilist* x y)
3001 (quasicons (car x) (f (cdr x))))))
3002 (define (quasivector x)
3004 (("quote" (x ...)) #'("quote" #(x ...)))
3006 (let f ((y x) (k (lambda (ls) #`("vector" #,@ls))))
3008 (("quote" (y ...)) (k #'(("quote" y) ...)))
3009 (("list" y ...) (k #'(y ...)))
3010 (("list*" y ... z) (f #'z (lambda (ls) (k (append #'(y ...) ls)))))
3011 (else #`("list->vector" #,x)))))))
3015 (("list" x ...) #`(list #,@(map emit #'(x ...))))
3016 ;; could emit list* for 3+ arguments if implementation supports
3019 (let f ((x* #'(x ...)))
3022 #`(cons #,(emit (car x*)) #,(f (cdr x*))))))
3023 (("append" x ...) #`(append #,@(map emit #'(x ...))))
3024 (("vector" x ...) #`(vector #,@(map emit #'(x ...))))
3025 (("list->vector" x) #`(list->vector #,(emit #'x)))
3029 ;; convert to intermediate language, combining introduced (but
3030 ;; not unquoted source) quote expressions where possible and
3031 ;; choosing optimal construction code otherwise, then emit
3032 ;; Scheme code corresponding to the intermediate language forms.
3033 ((_ e) (emit (quasi #'e 0)))))))
3035 (define-syntax include
3039 (let ((p (open-input-file fn)))
3040 (let f ((x (read p))
3044 (close-input-port p)
3047 (cons (datum->syntax k x) result)))))))
3050 (let ((fn (syntax->datum #'filename)))
3051 (with-syntax (((exp ...) (read-file fn #'filename)))
3052 #'(begin exp ...)))))))
3054 (define-syntax include-from-path
3058 (let ((fn (syntax->datum #'filename)))
3059 (with-syntax ((fn (datum->syntax
3061 (or (%search-load-path fn)
3062 (syntax-violation 'include-from-path
3063 "file not found in path"
3065 #'(include fn)))))))
3067 (define-syntax unquote
3069 (syntax-violation 'unquote
3070 "expression not valid outside of quasiquote"
3073 (define-syntax unquote-splicing
3075 (syntax-violation 'unquote-splicing
3076 "expression not valid outside of quasiquote"
3084 ((body (let f ((clause #'m1) (clauses #'(m2 ...)))
3086 (syntax-case clause (else)
3087 ((else e1 e2 ...) #'(begin e1 e2 ...))
3088 (((k ...) e1 e2 ...)
3089 #'(if (memv t '(k ...)) (begin e1 e2 ...)))
3090 (_ (syntax-violation 'case "bad clause" x clause)))
3091 (with-syntax ((rest (f (car clauses) (cdr clauses))))
3092 (syntax-case clause (else)
3093 (((k ...) e1 e2 ...)
3094 #'(if (memv t '(k ...))
3097 (_ (syntax-violation 'case "bad clause" x
3099 #'(let ((t e)) body))))))
3101 (define (make-variable-transformer proc)
3102 (if (procedure? proc)
3103 (let ((trans (lambda (x)
3104 #((macro-type . variable-transformer))
3106 (set-procedure-property! trans 'variable-transformer #t)
3108 (error "variable transformer not a procedure" proc)))
3110 (define-syntax identifier-syntax
3112 (syntax-case x (set!)
3115 #((macro-type . identifier-syntax))
3121 #'(e x (... ...))))))
3122 ((_ (id exp1) ((set! var val) exp2))
3123 (and (identifier? #'id) (identifier? #'var))
3124 #'(make-variable-transformer
3126 #((macro-type . variable-transformer))
3127 (syntax-case x (set!)
3128 ((set! var val) #'exp2)
3129 ((id x (... ...)) #'(exp1 x (... ...)))
3130 (id (identifier? #'id) #'exp1))))))))
3132 (define-syntax define*
3135 ((_ (id . args) b0 b1 ...)
3136 #'(define id (lambda* args b0 b1 ...)))
3137 ((_ id val) (identifier? #'x)
3138 #'(define id val)))))