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a63812a2 JB |
1 | ;;; Portable implementation of syntax-case |
2 | ;;; Extracted from Chez Scheme Version 5.9f | |
3 | ;;; Authors: R. Kent Dybvig, Oscar Waddell, Bob Hieb, Carl Bruggeman | |
4 | ||
5 | ;;; Copyright (c) 1992-1997 Cadence Research Systems | |
6 | ;;; Permission to copy this software, in whole or in part, to use this | |
7 | ;;; software for any lawful purpose, and to redistribute this software | |
8 | ;;; is granted subject to the restriction that all copies made of this | |
9 | ;;; software must include this copyright notice in full. This software | |
10 | ;;; is provided AS IS, with NO WARRANTY, EITHER EXPRESS OR IMPLIED, | |
11 | ;;; INCLUDING BUT NOT LIMITED TO IMPLIED WARRANTIES OF MERCHANTABILITY | |
12 | ;;; OR FITNESS FOR ANY PARTICULAR PURPOSE. IN NO EVENT SHALL THE | |
13 | ;;; AUTHORS BE LIABLE FOR CONSEQUENTIAL OR INCIDENTAL DAMAGES OF ANY | |
14 | ;;; NATURE WHATSOEVER. | |
15 | ||
16 | ||
17 | ;;; Before attempting to port this code to a new implementation of | |
18 | ;;; Scheme, please read the notes below carefully. | |
19 | ||
20 | ||
21 | ;;; This file defines the syntax-case expander, sc-expand, and a set | |
22 | ;;; of associated syntactic forms and procedures. Of these, the | |
23 | ;;; following are documented in The Scheme Programming Language, | |
24 | ;;; Second Edition (R. Kent Dybvig, Prentice Hall, 1996). Most are | |
25 | ;;; also documented in the R4RS and draft R5RS. | |
26 | ;;; | |
27 | ;;; bound-identifier=? | |
28 | ;;; datum->syntax-object | |
29 | ;;; define-syntax | |
30 | ;;; fluid-let-syntax | |
31 | ;;; free-identifier=? | |
32 | ;;; generate-temporaries | |
33 | ;;; identifier? | |
34 | ;;; identifier-syntax | |
35 | ;;; let-syntax | |
36 | ;;; letrec-syntax | |
37 | ;;; syntax | |
38 | ;;; syntax-case | |
39 | ;;; syntax-object->datum | |
40 | ;;; syntax-rules | |
41 | ;;; with-syntax | |
42 | ;;; | |
43 | ;;; All standard Scheme syntactic forms are supported by the expander | |
44 | ;;; or syntactic abstractions defined in this file. Only the R4RS | |
45 | ;;; delay is omitted, since its expansion is implementation-dependent. | |
46 | ||
47 | ;;; The remaining exports are listed below: | |
48 | ;;; | |
49 | ;;; (sc-expand datum) | |
50 | ;;; if datum represents a valid expression, sc-expand returns an | |
51 | ;;; expanded version of datum in a core language that includes no | |
52 | ;;; syntactic abstractions. The core language includes begin, | |
53 | ;;; define, if, lambda, letrec, quote, and set!. | |
54 | ;;; (eval-when situations expr ...) | |
55 | ;;; conditionally evaluates expr ... at compile-time or run-time | |
56 | ;;; depending upon situations (see the Chez Scheme System Manual, | |
57 | ;;; Revision 3, for a complete description) | |
58 | ;;; (syntax-error object message) | |
59 | ;;; used to report errors found during expansion | |
60 | ;;; (install-global-transformer symbol value) | |
61 | ;;; used by expanded code to install top-level syntactic abstractions | |
62 | ;;; (syntax-dispatch e p) | |
63 | ;;; used by expanded code to handle syntax-case matching | |
64 | ||
65 | ;;; The following nonstandard procedures must be provided by the | |
66 | ;;; implementation for this code to run. | |
67 | ;;; | |
68 | ;;; (void) | |
69 | ;;; returns the implementation's cannonical "unspecified value". This | |
70 | ;;; usually works: (define void (lambda () (if #f #f))). | |
71 | ;;; | |
72 | ;;; (andmap proc list1 list2 ...) | |
73 | ;;; returns true if proc returns true when applied to each element of list1 | |
74 | ;;; along with the corresponding elements of list2 .... | |
75 | ;;; The following definition works but does no error checking: | |
76 | ;;; | |
77 | ;;; (define andmap | |
78 | ;;; (lambda (f first . rest) | |
79 | ;;; (or (null? first) | |
80 | ;;; (if (null? rest) | |
81 | ;;; (let andmap ((first first)) | |
82 | ;;; (let ((x (car first)) (first (cdr first))) | |
83 | ;;; (if (null? first) | |
84 | ;;; (f x) | |
85 | ;;; (and (f x) (andmap first))))) | |
86 | ;;; (let andmap ((first first) (rest rest)) | |
87 | ;;; (let ((x (car first)) | |
88 | ;;; (xr (map car rest)) | |
89 | ;;; (first (cdr first)) | |
90 | ;;; (rest (map cdr rest))) | |
91 | ;;; (if (null? first) | |
92 | ;;; (apply f (cons x xr)) | |
93 | ;;; (and (apply f (cons x xr)) (andmap first rest))))))))) | |
94 | ;;; | |
95 | ;;; The following nonstandard procedures must also be provided by the | |
96 | ;;; implementation for this code to run using the standard portable | |
97 | ;;; hooks and output constructors. They are not used by expanded code, | |
98 | ;;; and so need be present only at expansion time. | |
99 | ;;; | |
100 | ;;; (eval x) | |
101 | ;;; where x is always in the form ("noexpand" expr). | |
102 | ;;; returns the value of expr. the "noexpand" flag is used to tell the | |
103 | ;;; evaluator/expander that no expansion is necessary, since expr has | |
104 | ;;; already been fully expanded to core forms. | |
105 | ;;; | |
106 | ;;; eval will not be invoked during the loading of psyntax.pp. After | |
107 | ;;; psyntax.pp has been loaded, the expansion of any macro definition, | |
108 | ;;; whether local or global, will result in a call to eval. If, however, | |
109 | ;;; sc-expand has already been registered as the expander to be used | |
110 | ;;; by eval, and eval accepts one argument, nothing special must be done | |
111 | ;;; to support the "noexpand" flag, since it is handled by sc-expand. | |
112 | ;;; | |
113 | ;;; (error who format-string why what) | |
114 | ;;; where who is either a symbol or #f, format-string is always "~a ~s", | |
115 | ;;; why is always a string, and what may be any object. error should | |
116 | ;;; signal an error with a message something like | |
117 | ;;; | |
118 | ;;; "error in <who>: <why> <what>" | |
119 | ;;; | |
120 | ;;; (gensym) | |
121 | ;;; returns a unique symbol each time it's called | |
122 | ;;; | |
123 | ;;; (putprop symbol key value) | |
124 | ;;; (getprop symbol key) | |
125 | ;;; key is always the symbol *sc-expander*; value may be any object. | |
126 | ;;; putprop should associate the given value with the given symbol in | |
127 | ;;; some way that it can be retrieved later with getprop. | |
128 | ||
129 | ;;; When porting to a new Scheme implementation, you should define the | |
130 | ;;; procedures listed above, load the expanded version of psyntax.ss | |
131 | ;;; (psyntax.pp, which should be available whereever you found | |
132 | ;;; psyntax.ss), and register sc-expand as the current expander (how | |
133 | ;;; you do this depends upon your implementation of Scheme). You may | |
134 | ;;; change the hooks and constructors defined toward the beginning of | |
135 | ;;; the code below, but to avoid bootstrapping problems, do so only | |
136 | ;;; after you have a working version of the expander. | |
137 | ||
138 | ;;; Chez Scheme allows the syntactic form (syntax <template>) to be | |
139 | ;;; abbreviated to #'<template>, just as (quote <datum>) may be | |
140 | ;;; abbreviated to '<datum>. The #' syntax makes programs written | |
141 | ;;; using syntax-case shorter and more readable and draws out the | |
142 | ;;; intuitive connection between syntax and quote. | |
143 | ||
144 | ;;; If you find that this code loads or runs slowly, consider | |
145 | ;;; switching to faster hardware or a faster implementation of | |
146 | ;;; Scheme. In Chez Scheme on a 200Mhz Pentium Pro, expanding, | |
147 | ;;; compiling (with full optimization), and loading this file takes | |
148 | ;;; between one and two seconds. | |
149 | ||
150 | ;;; In the expander implementation, we sometimes use syntactic abstractions | |
151 | ;;; when procedural abstractions would suffice. For example, we define | |
152 | ;;; top-wrap and top-marked? as | |
153 | ;;; (define-syntax top-wrap (identifier-syntax '((top)))) | |
154 | ;;; (define-syntax top-marked? | |
155 | ;;; (syntax-rules () | |
156 | ;;; ((_ w) (memq 'top (wrap-marks w))))) | |
157 | ;;; rather than | |
158 | ;;; (define top-wrap '((top))) | |
159 | ;;; (define top-marked? | |
160 | ;;; (lambda (w) (memq 'top (wrap-marks w)))) | |
161 | ;;; On ther other hand, we don't do this consistently; we define make-wrap, | |
162 | ;;; wrap-marks, and wrap-subst simply as | |
163 | ;;; (define make-wrap cons) | |
164 | ;;; (define wrap-marks car) | |
165 | ;;; (define wrap-subst cdr) | |
166 | ;;; In Chez Scheme, the syntactic and procedural forms of these | |
167 | ;;; abstractions are equivalent, since the optimizer consistently | |
168 | ;;; integrates constants and small procedures. Some Scheme | |
169 | ;;; implementations, however, may benefit from more consistent use | |
170 | ;;; of one form or the other. | |
171 | ||
172 | ||
173 | ;;; implementation information: | |
174 | ||
175 | ;;; "begin" is treated as a splicing construct at top level and at | |
176 | ;;; the beginning of bodies. Any sequence of expressions that would | |
177 | ;;; be allowed where the "begin" occurs is allowed. | |
178 | ||
179 | ;;; "let-syntax" and "letrec-syntax" are also treated as splicing | |
180 | ;;; constructs, in violation of the R4RS appendix and probably the R5RS | |
181 | ;;; when it comes out. A consequence, let-syntax and letrec-syntax do | |
182 | ;;; not create local contours, as do let and letrec. Although the | |
183 | ;;; functionality is greater as it is presently implemented, we will | |
184 | ;;; probably change it to conform to the R4RS/expected R5RS. | |
185 | ||
186 | ;;; Objects with no standard print syntax, including objects containing | |
187 | ;;; cycles and syntax object, are allowed in quoted data as long as they | |
188 | ;;; are contained within a syntax form or produced by datum->syntax-object. | |
189 | ;;; Such objects are never copied. | |
190 | ||
191 | ;;; All identifiers that don't have macro definitions and are not bound | |
192 | ;;; lexically are assumed to be global variables | |
193 | ||
194 | ;;; Top-level definitions of macro-introduced identifiers are allowed. | |
195 | ;;; This may not be appropriate for implementations in which the | |
196 | ;;; model is that bindings are created by definitions, as opposed to | |
197 | ;;; one in which initial values are assigned by definitions. | |
198 | ||
199 | ;;; Top-level variable definitions of syntax keywords is not permitted. | |
200 | ;;; Any solution allowing this would be kludgey and would yield | |
201 | ;;; surprising results in some cases. We can provide an undefine-syntax | |
202 | ;;; form. The questions is, should define be an implicit undefine-syntax? | |
203 | ;;; We've decided no for now. | |
204 | ||
205 | ;;; Identifiers and syntax objects are implemented as vectors for | |
206 | ;;; portability. As a result, it is possible to "forge" syntax | |
207 | ;;; objects. | |
208 | ||
209 | ;;; The implementation of generate-temporaries assumes that it is possible | |
210 | ;;; to generate globally unique symbols (gensyms). | |
211 | ||
212 | ;;; The input to sc-expand may contain "annotations" describing, e.g., the | |
213 | ;;; source file and character position from where each object was read if | |
214 | ;;; it was read from a file. These annotations are handled properly by | |
215 | ;;; sc-expand only if the annotation? hook (see hooks below) is implemented | |
216 | ;;; properly and the operators make-annotation, annotation-expression, | |
217 | ;;; annotation-source, annotation-stripped, and set-annotation-stripped! | |
218 | ;;; are supplied. If annotations are supplied, the proper annotation | |
219 | ;;; source is passed to the various output constructors, allowing | |
220 | ;;; implementations to accurately correlate source and expanded code. | |
221 | ;;; Contact one of the authors for details if you wish to make use of | |
222 | ;;; this feature. | |
223 | ||
224 | ||
225 | ||
226 | ;;; Bootstrapping: | |
227 | ||
228 | ;;; When changing syntax-object representations, it is necessary to support | |
229 | ;;; both old and new syntax-object representations in id-var-name. It | |
230 | ;;; should be sufficient to recognize old representations and treat | |
231 | ;;; them as not lexically bound. | |
232 | ||
233 | ||
234 | ||
235 | (let () | |
236 | (define-syntax define-structure | |
237 | (lambda (x) | |
238 | (define construct-name | |
239 | (lambda (template-identifier . args) | |
240 | (datum->syntax-object | |
241 | template-identifier | |
242 | (string->symbol | |
243 | (apply string-append | |
244 | (map (lambda (x) | |
245 | (if (string? x) | |
246 | x | |
247 | (symbol->string (syntax-object->datum x)))) | |
248 | args)))))) | |
249 | (syntax-case x () | |
250 | ((_ (name id1 ...)) | |
251 | (andmap identifier? (syntax (name id1 ...))) | |
252 | (with-syntax | |
253 | ((constructor (construct-name (syntax name) "make-" (syntax name))) | |
254 | (predicate (construct-name (syntax name) (syntax name) "?")) | |
255 | ((access ...) | |
256 | (map (lambda (x) (construct-name x (syntax name) "-" x)) | |
257 | (syntax (id1 ...)))) | |
258 | ((assign ...) | |
259 | (map (lambda (x) | |
260 | (construct-name x "set-" (syntax name) "-" x "!")) | |
261 | (syntax (id1 ...)))) | |
262 | (structure-length | |
263 | (+ (length (syntax (id1 ...))) 1)) | |
264 | ((index ...) | |
265 | (let f ((i 1) (ids (syntax (id1 ...)))) | |
266 | (if (null? ids) | |
267 | '() | |
268 | (cons i (f (+ i 1) (cdr ids))))))) | |
269 | (syntax (begin | |
270 | (define constructor | |
271 | (lambda (id1 ...) | |
272 | (vector 'name id1 ... ))) | |
273 | (define predicate | |
274 | (lambda (x) | |
275 | (and (vector? x) | |
276 | (= (vector-length x) structure-length) | |
277 | (eq? (vector-ref x 0) 'name)))) | |
278 | (define access | |
279 | (lambda (x) | |
280 | (vector-ref x index))) | |
281 | ... | |
282 | (define assign | |
283 | (lambda (x update) | |
284 | (vector-set! x index update))) | |
285 | ...))))))) | |
286 | ||
287 | (let () | |
288 | (define noexpand "noexpand") | |
289 | ||
290 | ;;; hooks to nonportable run-time helpers | |
291 | (begin | |
292 | (define fx+ +) | |
293 | (define fx- -) | |
294 | (define fx= =) | |
295 | (define fx< <) | |
296 | ||
297 | (define annotation? (lambda (x) #f)) | |
298 | ||
299 | (define top-level-eval-hook | |
300 | (lambda (x) | |
301 | (eval `(,noexpand ,x)))) | |
302 | ||
303 | (define local-eval-hook | |
304 | (lambda (x) | |
305 | (eval `(,noexpand ,x)))) | |
306 | ||
307 | (define error-hook | |
308 | (lambda (who why what) | |
309 | (error who "~a ~s" why what))) | |
310 | ||
311 | (define-syntax gensym-hook | |
312 | (syntax-rules () | |
313 | ((_) (gensym)))) | |
314 | ||
315 | (define put-global-definition-hook | |
316 | (lambda (symbol binding) | |
317 | (putprop symbol '*sc-expander* binding))) | |
318 | ||
319 | (define get-global-definition-hook | |
320 | (lambda (symbol) | |
321 | (getprop symbol '*sc-expander*))) | |
322 | ) | |
323 | ||
324 | ||
325 | ;;; output constructors | |
326 | (begin | |
327 | (define-syntax build-application | |
328 | (syntax-rules () | |
329 | ((_ source fun-exp arg-exps) | |
330 | `(,fun-exp . ,arg-exps)))) | |
331 | ||
332 | (define-syntax build-conditional | |
333 | (syntax-rules () | |
334 | ((_ source test-exp then-exp else-exp) | |
335 | `(if ,test-exp ,then-exp ,else-exp)))) | |
336 | ||
337 | (define-syntax build-lexical-reference | |
338 | (syntax-rules () | |
339 | ((_ type source var) | |
340 | var))) | |
341 | ||
342 | (define-syntax build-lexical-assignment | |
343 | (syntax-rules () | |
344 | ((_ source var exp) | |
345 | `(set! ,var ,exp)))) | |
346 | ||
347 | (define-syntax build-global-reference | |
348 | (syntax-rules () | |
349 | ((_ source var) | |
350 | var))) | |
351 | ||
352 | (define-syntax build-global-assignment | |
353 | (syntax-rules () | |
354 | ((_ source var exp) | |
355 | `(set! ,var ,exp)))) | |
356 | ||
357 | (define-syntax build-global-definition | |
358 | (syntax-rules () | |
359 | ((_ source var exp) | |
360 | `(define ,var ,exp)))) | |
361 | ||
362 | (define-syntax build-lambda | |
363 | (syntax-rules () | |
364 | ((_ src vars exp) | |
365 | `(lambda ,vars ,exp)))) | |
366 | ||
367 | (define-syntax build-primref | |
368 | (syntax-rules () | |
369 | ((_ src name) name) | |
370 | ((_ src level name) name))) | |
371 | ||
372 | (define-syntax build-data | |
373 | (syntax-rules () | |
374 | ((_ src exp) `',exp))) | |
375 | ||
376 | (define build-sequence | |
377 | (lambda (src exps) | |
378 | (if (null? (cdr exps)) | |
379 | (car exps) | |
380 | `(begin ,@exps)))) | |
381 | ||
382 | (define build-let | |
383 | (lambda (src vars val-exps body-exp) | |
384 | (if (null? vars) | |
385 | body-exp | |
386 | `(let ,(map list vars val-exps) ,body-exp)))) | |
387 | ||
388 | (define build-named-let | |
389 | (lambda (src vars val-exps body-exp) | |
390 | (if (null? vars) | |
391 | body-exp | |
392 | `(let ,(car vars) ,(map list (cdr vars) val-exps) ,body-exp)))) | |
393 | ||
394 | (define build-letrec | |
395 | (lambda (src vars val-exps body-exp) | |
396 | (if (null? vars) | |
397 | body-exp | |
398 | `(letrec ,(map list vars val-exps) ,body-exp)))) | |
399 | ||
400 | (define-syntax build-lexical-var | |
401 | (syntax-rules () | |
402 | ((_ src id) (gensym id generated-symbols)))) | |
403 | ||
404 | (define-syntax self-evaluating? | |
405 | (syntax-rules () | |
406 | ((_ e) | |
407 | (let ((x e)) | |
408 | (or (boolean? x) (number? x) (string? x) (char? x) (null? x) (keyword? x)))))) | |
409 | ) | |
410 | ||
411 | (define-structure (syntax-object expression wrap)) | |
412 | ||
413 | (define-syntax unannotate | |
414 | (syntax-rules () | |
415 | ((_ x) | |
416 | (let ((e x)) | |
417 | (if (annotation? e) | |
418 | (annotation-expression e) | |
419 | e))))) | |
420 | ||
421 | (define-syntax no-source (identifier-syntax #f)) | |
422 | ||
423 | (define source-annotation | |
424 | (lambda (x) | |
425 | (cond | |
426 | ((annotation? x) (annotation-source x)) | |
427 | ((syntax-object? x) (source-annotation (syntax-object-expression x))) | |
428 | (else no-source)))) | |
429 | ||
430 | (define-syntax arg-check | |
431 | (syntax-rules () | |
432 | ((_ pred? e who) | |
433 | (let ((x e)) | |
434 | (if (not (pred? x)) (error-hook who "invalid argument" x)))))) | |
435 | ||
436 | ;;; compile-time environments | |
437 | ||
438 | ;;; wrap and environment comprise two level mapping. | |
439 | ;;; wrap : id --> label | |
440 | ;;; env : label --> <element> | |
441 | ||
442 | ;;; environments are represented in two parts: a lexical part and a global | |
443 | ;;; part. The lexical part is a simple list of associations from labels | |
444 | ;;; to bindings. The global part is implemented by | |
445 | ;;; {put,get}-global-definition-hook and associates symbols with | |
446 | ;;; bindings. | |
447 | ||
448 | ;;; global (assumed global variable) and displaced-lexical (see below) | |
449 | ;;; do not show up in any environment; instead, they are fabricated by | |
450 | ;;; lookup when it finds no other bindings. | |
451 | ||
452 | ;;; <environment> ::= ((<label> . <binding>)*) | |
453 | ||
454 | ;;; identifier bindings include a type and a value | |
455 | ||
456 | ;;; <binding> ::= (macro . <procedure>) macros | |
457 | ;;; (core . <procedure>) core forms | |
458 | ;;; (begin) begin | |
459 | ;;; (define) define | |
460 | ;;; (define-syntax) define-syntax | |
461 | ;;; (local-syntax . rec?) let-syntax/letrec-syntax | |
462 | ;;; (eval-when) eval-when | |
463 | ;;; (syntax . (<var> . <level>)) pattern variables | |
464 | ;;; (global) assumed global variable | |
465 | ;;; (lexical . <var>) lexical variables | |
466 | ;;; (displaced-lexical) displaced lexicals | |
467 | ;;; <level> ::= <nonnegative integer> | |
468 | ;;; <var> ::= variable returned by build-lexical-var | |
469 | ||
470 | ;;; a macro is a user-defined syntactic-form. a core is a system-defined | |
471 | ;;; syntactic form. begin, define, define-syntax, and eval-when are | |
472 | ;;; treated specially since they are sensitive to whether the form is | |
473 | ;;; at top-level and (except for eval-when) can denote valid internal | |
474 | ;;; definitions. | |
475 | ||
476 | ;;; a pattern variable is a variable introduced by syntax-case and can | |
477 | ;;; be referenced only within a syntax form. | |
478 | ||
479 | ;;; any identifier for which no top-level syntax definition or local | |
480 | ;;; binding of any kind has been seen is assumed to be a global | |
481 | ;;; variable. | |
482 | ||
483 | ;;; a lexical variable is a lambda- or letrec-bound variable. | |
484 | ||
485 | ;;; a displaced-lexical identifier is a lexical identifier removed from | |
486 | ;;; it's scope by the return of a syntax object containing the identifier. | |
487 | ;;; a displaced lexical can also appear when a letrec-syntax-bound | |
488 | ;;; keyword is referenced on the rhs of one of the letrec-syntax clauses. | |
489 | ;;; a displaced lexical should never occur with properly written macros. | |
490 | ||
491 | (define-syntax make-binding | |
492 | (syntax-rules (quote) | |
493 | ((_ type value) (cons type value)) | |
494 | ((_ 'type) '(type)) | |
495 | ((_ type) (cons type '())))) | |
496 | (define binding-type car) | |
497 | (define binding-value cdr) | |
498 | ||
499 | (define-syntax null-env (identifier-syntax '())) | |
500 | ||
501 | (define extend-env | |
502 | (lambda (labels bindings r) | |
503 | (if (null? labels) | |
504 | r | |
505 | (extend-env (cdr labels) (cdr bindings) | |
506 | (cons (cons (car labels) (car bindings)) r))))) | |
507 | ||
508 | (define extend-var-env | |
509 | ; variant of extend-env that forms "lexical" binding | |
510 | (lambda (labels vars r) | |
511 | (if (null? labels) | |
512 | r | |
513 | (extend-var-env (cdr labels) (cdr vars) | |
514 | (cons (cons (car labels) (make-binding 'lexical (car vars))) r))))) | |
515 | ||
516 | ;;; we use a "macros only" environment in expansion of local macro | |
517 | ;;; definitions so that their definitions can use local macros without | |
518 | ;;; attempting to use other lexical identifiers. | |
519 | (define macros-only-env | |
520 | (lambda (r) | |
521 | (if (null? r) | |
522 | '() | |
523 | (let ((a (car r))) | |
524 | (if (eq? (cadr a) 'macro) | |
525 | (cons a (macros-only-env (cdr r))) | |
526 | (macros-only-env (cdr r))))))) | |
527 | ||
528 | (define lookup | |
529 | ; x may be a label or a symbol | |
530 | ; although symbols are usually global, we check the environment first | |
531 | ; anyway because a temporary binding may have been established by | |
532 | ; fluid-let-syntax | |
533 | (lambda (x r) | |
534 | (cond | |
535 | ((assq x r) => cdr) | |
536 | ((symbol? x) | |
537 | (or (get-global-definition-hook x) (make-binding 'global))) | |
538 | (else (make-binding 'displaced-lexical))))) | |
539 | ||
540 | (define global-extend | |
541 | (lambda (type sym val) | |
542 | (put-global-definition-hook sym (make-binding type val)))) | |
543 | ||
544 | ||
545 | ;;; Conceptually, identifiers are always syntax objects. Internally, | |
546 | ;;; however, the wrap is sometimes maintained separately (a source of | |
547 | ;;; efficiency and confusion), so that symbols are also considered | |
548 | ;;; identifiers by id?. Externally, they are always wrapped. | |
549 | ||
550 | (define nonsymbol-id? | |
551 | (lambda (x) | |
552 | (and (syntax-object? x) | |
553 | (symbol? (unannotate (syntax-object-expression x)))))) | |
554 | ||
555 | (define id? | |
556 | (lambda (x) | |
557 | (cond | |
558 | ((symbol? x) #t) | |
559 | ((syntax-object? x) (symbol? (unannotate (syntax-object-expression x)))) | |
560 | ((annotation? x) (symbol? (annotation-expression x))) | |
561 | (else #f)))) | |
562 | ||
563 | (define-syntax id-sym-name | |
564 | (syntax-rules () | |
565 | ((_ e) | |
566 | (let ((x e)) | |
567 | (unannotate (if (syntax-object? x) (syntax-object-expression x) x)))))) | |
568 | ||
569 | (define id-sym-name&marks | |
570 | (lambda (x w) | |
571 | (if (syntax-object? x) | |
572 | (values | |
573 | (unannotate (syntax-object-expression x)) | |
574 | (join-marks (wrap-marks w) (wrap-marks (syntax-object-wrap x)))) | |
575 | (values (unannotate x) (wrap-marks w))))) | |
576 | ||
577 | ;;; syntax object wraps | |
578 | ||
579 | ;;; <wrap> ::= ((<mark> ...) . (<subst> ...)) | |
580 | ;;; <subst> ::= <shift> | <subs> | |
581 | ;;; <subs> ::= #(<old name> <label> (<mark> ...)) | |
582 | ;;; <shift> ::= positive fixnum | |
583 | ||
584 | (define make-wrap cons) | |
585 | (define wrap-marks car) | |
586 | (define wrap-subst cdr) | |
587 | ||
588 | (define-syntax subst-rename? (identifier-syntax vector?)) | |
589 | (define-syntax rename-old (syntax-rules () ((_ x) (vector-ref x 0)))) | |
590 | (define-syntax rename-new (syntax-rules () ((_ x) (vector-ref x 1)))) | |
591 | (define-syntax rename-marks (syntax-rules () ((_ x) (vector-ref x 2)))) | |
592 | (define-syntax make-rename | |
593 | (syntax-rules () | |
594 | ((_ old new marks) (vector old new marks)))) | |
595 | ||
596 | ;;; labels must be comparable with "eq?" and distinct from symbols. | |
597 | (define gen-label | |
598 | (lambda () (string #\i))) | |
599 | ||
600 | (define gen-labels | |
601 | (lambda (ls) | |
602 | (if (null? ls) | |
603 | '() | |
604 | (cons (gen-label) (gen-labels (cdr ls)))))) | |
605 | ||
606 | (define-structure (ribcage symnames marks labels)) | |
607 | ||
608 | (define-syntax empty-wrap (identifier-syntax '(()))) | |
609 | ||
610 | (define-syntax top-wrap (identifier-syntax '((top)))) | |
611 | ||
612 | (define-syntax top-marked? | |
613 | (syntax-rules () | |
614 | ((_ w) (memq 'top (wrap-marks w))))) | |
615 | ||
616 | ;;; Marks must be comparable with "eq?" and distinct from pairs and | |
617 | ;;; the symbol top. We do not use integers so that marks will remain | |
618 | ;;; unique even across file compiles. | |
619 | ||
620 | (define-syntax the-anti-mark (identifier-syntax #f)) | |
621 | ||
622 | (define anti-mark | |
623 | (lambda (w) | |
624 | (make-wrap (cons the-anti-mark (wrap-marks w)) | |
625 | (cons 'shift (wrap-subst w))))) | |
626 | ||
627 | (define-syntax new-mark | |
628 | (syntax-rules () | |
629 | ((_) (string #\m)))) | |
630 | ||
631 | ;;; make-empty-ribcage and extend-ribcage maintain list-based ribcages for | |
632 | ;;; internal definitions, in which the ribcages are built incrementally | |
633 | (define-syntax make-empty-ribcage | |
634 | (syntax-rules () | |
635 | ((_) (make-ribcage '() '() '())))) | |
636 | ||
637 | (define extend-ribcage! | |
638 | ; must receive ids with complete wraps | |
639 | (lambda (ribcage id label) | |
640 | (set-ribcage-symnames! ribcage | |
641 | (cons (unannotate (syntax-object-expression id)) | |
642 | (ribcage-symnames ribcage))) | |
643 | (set-ribcage-marks! ribcage | |
644 | (cons (wrap-marks (syntax-object-wrap id)) | |
645 | (ribcage-marks ribcage))) | |
646 | (set-ribcage-labels! ribcage | |
647 | (cons label (ribcage-labels ribcage))))) | |
648 | ||
649 | ;;; make-binding-wrap creates vector-based ribcages | |
650 | (define make-binding-wrap | |
651 | (lambda (ids labels w) | |
652 | (if (null? ids) | |
653 | w | |
654 | (make-wrap | |
655 | (wrap-marks w) | |
656 | (cons | |
657 | (let ((labelvec (list->vector labels))) | |
658 | (let ((n (vector-length labelvec))) | |
659 | (let ((symnamevec (make-vector n)) (marksvec (make-vector n))) | |
660 | (let f ((ids ids) (i 0)) | |
661 | (if (not (null? ids)) | |
662 | (call-with-values | |
663 | (lambda () (id-sym-name&marks (car ids) w)) | |
664 | (lambda (symname marks) | |
665 | (vector-set! symnamevec i symname) | |
666 | (vector-set! marksvec i marks) | |
667 | (f (cdr ids) (fx+ i 1)))))) | |
668 | (make-ribcage symnamevec marksvec labelvec)))) | |
669 | (wrap-subst w)))))) | |
670 | ||
671 | (define smart-append | |
672 | (lambda (m1 m2) | |
673 | (if (null? m2) | |
674 | m1 | |
675 | (append m1 m2)))) | |
676 | ||
677 | (define join-wraps | |
678 | (lambda (w1 w2) | |
679 | (let ((m1 (wrap-marks w1)) (s1 (wrap-subst w1))) | |
680 | (if (null? m1) | |
681 | (if (null? s1) | |
682 | w2 | |
683 | (make-wrap | |
684 | (wrap-marks w2) | |
685 | (smart-append s1 (wrap-subst w2)))) | |
686 | (make-wrap | |
687 | (smart-append m1 (wrap-marks w2)) | |
688 | (smart-append s1 (wrap-subst w2))))))) | |
689 | ||
690 | (define join-marks | |
691 | (lambda (m1 m2) | |
692 | (smart-append m1 m2))) | |
693 | ||
694 | (define same-marks? | |
695 | (lambda (x y) | |
696 | (or (eq? x y) | |
697 | (and (not (null? x)) | |
698 | (not (null? y)) | |
699 | (eq? (car x) (car y)) | |
700 | (same-marks? (cdr x) (cdr y)))))) | |
701 | ||
702 | (define id-var-name | |
703 | (lambda (id w) | |
704 | (define-syntax first | |
705 | (syntax-rules () | |
706 | ((_ e) (call-with-values (lambda () e) (lambda (x . ignore) x))))) | |
707 | (define search | |
708 | (lambda (sym subst marks) | |
709 | (if (null? subst) | |
710 | (values #f marks) | |
711 | (let ((fst (car subst))) | |
712 | (if (eq? fst 'shift) | |
713 | (search sym (cdr subst) (cdr marks)) | |
714 | (let ((symnames (ribcage-symnames fst))) | |
715 | (if (vector? symnames) | |
716 | (search-vector-rib sym subst marks symnames fst) | |
717 | (search-list-rib sym subst marks symnames fst)))))))) | |
718 | (define search-list-rib | |
719 | (lambda (sym subst marks symnames ribcage) | |
720 | (let f ((symnames symnames) (i 0)) | |
721 | (cond | |
722 | ((null? symnames) (search sym (cdr subst) marks)) | |
723 | ((and (eq? (car symnames) sym) | |
724 | (same-marks? marks (list-ref (ribcage-marks ribcage) i))) | |
725 | (values (list-ref (ribcage-labels ribcage) i) marks)) | |
726 | (else (f (cdr symnames) (fx+ i 1))))))) | |
727 | (define search-vector-rib | |
728 | (lambda (sym subst marks symnames ribcage) | |
729 | (let ((n (vector-length symnames))) | |
730 | (let f ((i 0)) | |
731 | (cond | |
732 | ((fx= i n) (search sym (cdr subst) marks)) | |
733 | ((and (eq? (vector-ref symnames i) sym) | |
734 | (same-marks? marks (vector-ref (ribcage-marks ribcage) i))) | |
735 | (values (vector-ref (ribcage-labels ribcage) i) marks)) | |
736 | (else (f (fx+ i 1)))))))) | |
737 | (cond | |
738 | ((symbol? id) | |
739 | (or (first (search id (wrap-subst w) (wrap-marks w))) id)) | |
740 | ((syntax-object? id) | |
741 | (let ((id (unannotate (syntax-object-expression id))) | |
742 | (w1 (syntax-object-wrap id))) | |
743 | (let ((marks (join-marks (wrap-marks w) (wrap-marks w1)))) | |
744 | (call-with-values (lambda () (search id (wrap-subst w) marks)) | |
745 | (lambda (new-id marks) | |
746 | (or new-id | |
747 | (first (search id (wrap-subst w1) marks)) | |
748 | id)))))) | |
749 | ((annotation? id) | |
750 | (let ((id (unannotate id))) | |
751 | (or (first (search id (wrap-subst w) (wrap-marks w))) id))) | |
752 | (else (error-hook 'id-var-name "invalid id" id))))) | |
753 | ||
754 | ;;; free-id=? must be passed fully wrapped ids since (free-id=? x y) | |
755 | ;;; may be true even if (free-id=? (wrap x w) (wrap y w)) is not. | |
756 | ||
757 | (define free-id=? | |
758 | (lambda (i j) | |
759 | (and (eq? (id-sym-name i) (id-sym-name j)) ; accelerator | |
760 | (eq? (id-var-name i empty-wrap) (id-var-name j empty-wrap))))) | |
761 | ||
762 | ;;; bound-id=? may be passed unwrapped (or partially wrapped) ids as | |
763 | ;;; long as the missing portion of the wrap is common to both of the ids | |
764 | ;;; since (bound-id=? x y) iff (bound-id=? (wrap x w) (wrap y w)) | |
765 | ||
766 | (define bound-id=? | |
767 | (lambda (i j) | |
768 | (if (and (syntax-object? i) (syntax-object? j)) | |
769 | (and (eq? (unannotate (syntax-object-expression i)) | |
770 | (unannotate (syntax-object-expression j))) | |
771 | (same-marks? (wrap-marks (syntax-object-wrap i)) | |
772 | (wrap-marks (syntax-object-wrap j)))) | |
773 | (eq? (unannotate i) (unannotate j))))) | |
774 | ||
775 | ;;; "valid-bound-ids?" returns #t if it receives a list of distinct ids. | |
776 | ;;; valid-bound-ids? may be passed unwrapped (or partially wrapped) ids | |
777 | ;;; as long as the missing portion of the wrap is common to all of the | |
778 | ;;; ids. | |
779 | ||
780 | (define valid-bound-ids? | |
781 | (lambda (ids) | |
782 | (and (let all-ids? ((ids ids)) | |
783 | (or (null? ids) | |
784 | (and (id? (car ids)) | |
785 | (all-ids? (cdr ids))))) | |
786 | (distinct-bound-ids? ids)))) | |
787 | ||
788 | ;;; distinct-bound-ids? expects a list of ids and returns #t if there are | |
789 | ;;; no duplicates. It is quadratic on the length of the id list; long | |
790 | ;;; lists could be sorted to make it more efficient. distinct-bound-ids? | |
791 | ;;; may be passed unwrapped (or partially wrapped) ids as long as the | |
792 | ;;; missing portion of the wrap is common to all of the ids. | |
793 | ||
794 | (define distinct-bound-ids? | |
795 | (lambda (ids) | |
796 | (let distinct? ((ids ids)) | |
797 | (or (null? ids) | |
798 | (and (not (bound-id-member? (car ids) (cdr ids))) | |
799 | (distinct? (cdr ids))))))) | |
800 | ||
801 | (define bound-id-member? | |
802 | (lambda (x list) | |
803 | (and (not (null? list)) | |
804 | (or (bound-id=? x (car list)) | |
805 | (bound-id-member? x (cdr list)))))) | |
806 | ||
807 | ;;; wrapping expressions and identifiers | |
808 | ||
809 | (define wrap | |
810 | (lambda (x w) | |
811 | (cond | |
812 | ((and (null? (wrap-marks w)) (null? (wrap-subst w))) x) | |
813 | ((syntax-object? x) | |
814 | (make-syntax-object | |
815 | (syntax-object-expression x) | |
816 | (join-wraps w (syntax-object-wrap x)))) | |
817 | ((null? x) x) | |
818 | (else (make-syntax-object x w))))) | |
819 | ||
820 | (define source-wrap | |
821 | (lambda (x w s) | |
822 | (wrap (if s (make-annotation x s #f) x) w))) | |
823 | ||
824 | ;;; expanding | |
825 | ||
826 | (define chi-sequence | |
827 | (lambda (body r w s) | |
828 | (build-sequence s | |
829 | (let dobody ((body body) (r r) (w w)) | |
830 | (if (null? body) | |
831 | '() | |
832 | (let ((first (chi (car body) r w))) | |
833 | (cons first (dobody (cdr body) r w)))))))) | |
834 | ||
835 | (define chi-top-sequence | |
836 | (lambda (body r w s m esew) | |
837 | (build-sequence s | |
838 | (let dobody ((body body) (r r) (w w) (m m) (esew esew)) | |
839 | (if (null? body) | |
840 | '() | |
841 | (let ((first (chi-top (car body) r w m esew))) | |
842 | (cons first (dobody (cdr body) r w m esew)))))))) | |
843 | ||
844 | (define chi-install-global | |
845 | (lambda (name e) | |
846 | (build-application no-source | |
847 | (build-primref no-source 'install-global-transformer) | |
848 | (list (build-data no-source name) e)))) | |
849 | ||
850 | (define chi-when-list | |
851 | (lambda (e when-list w) | |
852 | ; when-list is syntax'd version of list of situations | |
853 | (let f ((when-list when-list) (situations '())) | |
854 | (if (null? when-list) | |
855 | situations | |
856 | (f (cdr when-list) | |
857 | (cons (let ((x (car when-list))) | |
858 | (cond | |
859 | ((free-id=? x (syntax compile)) 'compile) | |
860 | ((free-id=? x (syntax load)) 'load) | |
861 | ((free-id=? x (syntax eval)) 'eval) | |
862 | (else (syntax-error (wrap x w) | |
863 | "invalid eval-when situation")))) | |
864 | situations)))))) | |
865 | ||
866 | ;;; syntax-type returns five values: type, value, e, w, and s. The first | |
867 | ;;; two are described in the table below. | |
868 | ;;; | |
869 | ;;; type value explanation | |
870 | ;;; ------------------------------------------------------------------- | |
871 | ;;; core procedure core form (including singleton) | |
872 | ;;; lexical name lexical variable reference | |
873 | ;;; global name global variable reference | |
874 | ;;; begin none begin keyword | |
875 | ;;; define none define keyword | |
876 | ;;; define-syntax none define-syntax keyword | |
877 | ;;; local-syntax rec? letrec-syntax/let-syntax keyword | |
878 | ;;; eval-when none eval-when keyword | |
879 | ;;; syntax level pattern variable | |
880 | ;;; displaced-lexical none displaced lexical identifier | |
881 | ;;; lexical-call name call to lexical variable | |
882 | ;;; global-call name call to global variable | |
883 | ;;; call none any other call | |
884 | ;;; begin-form none begin expression | |
885 | ;;; define-form id variable definition | |
886 | ;;; define-syntax-form id syntax definition | |
887 | ;;; local-syntax-form rec? syntax definition | |
888 | ;;; eval-when-form none eval-when form | |
889 | ;;; constant none self-evaluating datum | |
890 | ;;; other none anything else | |
891 | ;;; | |
892 | ;;; For define-form and define-syntax-form, e is the rhs expression. | |
893 | ;;; For all others, e is the entire form. w is the wrap for e. | |
894 | ;;; s is the source for the entire form. | |
895 | ;;; | |
896 | ;;; syntax-type expands macros and unwraps as necessary to get to | |
897 | ;;; one of the forms above. It also parses define and define-syntax | |
898 | ;;; forms, although perhaps this should be done by the consumer. | |
899 | ||
900 | (define syntax-type | |
901 | (lambda (e r w s rib) | |
902 | (cond | |
903 | ((symbol? e) | |
904 | (let* ((n (id-var-name e w)) | |
905 | (b (lookup n r)) | |
906 | (type (binding-type b))) | |
907 | (case type | |
908 | ((lexical) (values type (binding-value b) e w s)) | |
909 | ((global) (values type n e w s)) | |
910 | ((macro) | |
911 | (syntax-type (chi-macro (binding-value b) e r w rib) r empty-wrap s rib)) | |
912 | (else (values type (binding-value b) e w s))))) | |
913 | ((pair? e) | |
914 | (let ((first (car e))) | |
915 | (if (id? first) | |
916 | (let* ((n (id-var-name first w)) | |
917 | (b (lookup n r)) | |
918 | (type (binding-type b))) | |
919 | (case type | |
920 | ((lexical) (values 'lexical-call (binding-value b) e w s)) | |
921 | ((global) (values 'global-call n e w s)) | |
922 | ((macro) | |
923 | (syntax-type (chi-macro (binding-value b) e r w rib) | |
924 | r empty-wrap s rib)) | |
925 | ((core) (values type (binding-value b) e w s)) | |
926 | ((local-syntax) | |
927 | (values 'local-syntax-form (binding-value b) e w s)) | |
928 | ((begin) (values 'begin-form #f e w s)) | |
929 | ((eval-when) (values 'eval-when-form #f e w s)) | |
930 | ((define) | |
931 | (syntax-case e () | |
932 | ((_ name val) | |
933 | (id? (syntax name)) | |
934 | (values 'define-form (syntax name) (syntax val) w s)) | |
935 | ((_ (name . args) e1 e2 ...) | |
936 | (and (id? (syntax name)) | |
937 | (valid-bound-ids? (lambda-var-list (syntax args)))) | |
938 | ; need lambda here... | |
939 | (values 'define-form (wrap (syntax name) w) | |
940 | (cons (syntax lambda) (wrap (syntax (args e1 e2 ...)) w)) | |
941 | empty-wrap s)) | |
942 | ((_ name) | |
943 | (id? (syntax name)) | |
944 | (values 'define-form (wrap (syntax name) w) | |
945 | (syntax (void)) | |
946 | empty-wrap s)))) | |
947 | ((define-syntax) | |
948 | (syntax-case e () | |
949 | ((_ name val) | |
950 | (id? (syntax name)) | |
951 | (values 'define-syntax-form (syntax name) | |
952 | (syntax val) w s)))) | |
953 | (else (values 'call #f e w s)))) | |
954 | (values 'call #f e w s)))) | |
955 | ((syntax-object? e) | |
956 | ;; s can't be valid source if we've unwrapped | |
957 | (syntax-type (syntax-object-expression e) | |
958 | r | |
959 | (join-wraps w (syntax-object-wrap e)) | |
960 | no-source rib)) | |
961 | ((annotation? e) | |
962 | (syntax-type (annotation-expression e) r w (annotation-source e) rib)) | |
963 | ((self-evaluating? e) (values 'constant #f e w s)) | |
964 | (else (values 'other #f e w s))))) | |
965 | ||
966 | (define chi-top | |
967 | (lambda (e r w m esew) | |
968 | (define-syntax eval-if-c&e | |
969 | (syntax-rules () | |
970 | ((_ m e) | |
971 | (let ((x e)) | |
972 | (if (eq? m 'c&e) (top-level-eval-hook x)) | |
973 | x)))) | |
974 | (call-with-values | |
975 | (lambda () (syntax-type e r w no-source #f)) | |
976 | (lambda (type value e w s) | |
977 | (case type | |
978 | ((begin-form) | |
979 | (syntax-case e () | |
980 | ((_) (chi-void)) | |
981 | ((_ e1 e2 ...) | |
982 | (chi-top-sequence (syntax (e1 e2 ...)) r w s m esew)))) | |
983 | ((local-syntax-form) | |
984 | (chi-local-syntax value e r w s | |
985 | (lambda (body r w s) | |
986 | (chi-top-sequence body r w s m esew)))) | |
987 | ((eval-when-form) | |
988 | (syntax-case e () | |
989 | ((_ (x ...) e1 e2 ...) | |
990 | (let ((when-list (chi-when-list e (syntax (x ...)) w)) | |
991 | (body (syntax (e1 e2 ...)))) | |
992 | (cond | |
993 | ((eq? m 'e) | |
994 | (if (memq 'eval when-list) | |
995 | (chi-top-sequence body r w s 'e '(eval)) | |
996 | (chi-void))) | |
997 | ((memq 'load when-list) | |
998 | (if (or (memq 'compile when-list) | |
999 | (and (eq? m 'c&e) (memq 'eval when-list))) | |
1000 | (chi-top-sequence body r w s 'c&e '(compile load)) | |
1001 | (if (memq m '(c c&e)) | |
1002 | (chi-top-sequence body r w s 'c '(load)) | |
1003 | (chi-void)))) | |
1004 | ((or (memq 'compile when-list) | |
1005 | (and (eq? m 'c&e) (memq 'eval when-list))) | |
1006 | (top-level-eval-hook | |
1007 | (chi-top-sequence body r w s 'e '(eval))) | |
1008 | (chi-void)) | |
1009 | (else (chi-void))))))) | |
1010 | ((define-syntax-form) | |
1011 | (let ((n (id-var-name value w)) (r (macros-only-env r))) | |
1012 | (case m | |
1013 | ((c) | |
1014 | (if (memq 'compile esew) | |
1015 | (let ((e (chi-install-global n (chi e r w)))) | |
1016 | (top-level-eval-hook e) | |
1017 | (if (memq 'load esew) e (chi-void))) | |
1018 | (if (memq 'load esew) | |
1019 | (chi-install-global n (chi e r w)) | |
1020 | (chi-void)))) | |
1021 | ((c&e) | |
1022 | (let ((e (chi-install-global n (chi e r w)))) | |
1023 | (top-level-eval-hook e) | |
1024 | e)) | |
1025 | (else | |
1026 | (if (memq 'eval esew) | |
1027 | (top-level-eval-hook | |
1028 | (chi-install-global n (chi e r w)))) | |
1029 | (chi-void))))) | |
1030 | ((define-form) | |
1031 | (let ((n (id-var-name value w))) | |
1032 | (case (binding-type (lookup n r)) | |
1033 | ((global) | |
1034 | (eval-if-c&e m | |
1035 | (build-global-definition s n (chi e r w)))) | |
1036 | ((displaced-lexical) | |
1037 | (syntax-error (wrap value w) "identifier out of context")) | |
1038 | (else (syntax-error (wrap value w) | |
1039 | "cannot define keyword at top level"))))) | |
1040 | (else (eval-if-c&e m (chi-expr type value e r w s)))))))) | |
1041 | ||
1042 | (define chi | |
1043 | (lambda (e r w) | |
1044 | (call-with-values | |
1045 | (lambda () (syntax-type e r w no-source #f)) | |
1046 | (lambda (type value e w s) | |
1047 | (chi-expr type value e r w s))))) | |
1048 | ||
1049 | (define chi-expr | |
1050 | (lambda (type value e r w s) | |
1051 | (case type | |
1052 | ((lexical) | |
1053 | (build-lexical-reference 'value s value)) | |
1054 | ((core) (value e r w s)) | |
1055 | ((lexical-call) | |
1056 | (chi-application | |
1057 | (build-lexical-reference 'fun (source-annotation (car e)) value) | |
1058 | e r w s)) | |
1059 | ((global-call) | |
1060 | (chi-application | |
1061 | (build-global-reference (source-annotation (car e)) value) | |
1062 | e r w s)) | |
1063 | ((constant) (build-data s (strip (source-wrap e w s) empty-wrap))) | |
1064 | ((global) (build-global-reference s value)) | |
1065 | ((call) (chi-application (chi (car e) r w) e r w s)) | |
1066 | ((begin-form) | |
1067 | (syntax-case e () | |
1068 | ((_ e1 e2 ...) (chi-sequence (syntax (e1 e2 ...)) r w s)))) | |
1069 | ((local-syntax-form) | |
1070 | (chi-local-syntax value e r w s chi-sequence)) | |
1071 | ((eval-when-form) | |
1072 | (syntax-case e () | |
1073 | ((_ (x ...) e1 e2 ...) | |
1074 | (let ((when-list (chi-when-list e (syntax (x ...)) w))) | |
1075 | (if (memq 'eval when-list) | |
1076 | (chi-sequence (syntax (e1 e2 ...)) r w s) | |
1077 | (chi-void)))))) | |
1078 | ((define-form define-syntax-form) | |
1079 | (syntax-error (wrap value w) "invalid context for definition of")) | |
1080 | ((syntax) | |
1081 | (syntax-error (source-wrap e w s) | |
1082 | "reference to pattern variable outside syntax form")) | |
1083 | ((displaced-lexical) | |
1084 | (syntax-error (source-wrap e w s) | |
1085 | "reference to identifier outside its scope")) | |
1086 | (else (syntax-error (source-wrap e w s)))))) | |
1087 | ||
1088 | (define chi-application | |
1089 | (lambda (x e r w s) | |
1090 | (syntax-case e () | |
1091 | ((e0 e1 ...) | |
1092 | (build-application s x | |
1093 | (map (lambda (e) (chi e r w)) (syntax (e1 ...)))))))) | |
1094 | ||
1095 | (define chi-macro | |
1096 | (lambda (p e r w rib) | |
1097 | (define rebuild-macro-output | |
1098 | (lambda (x m) | |
1099 | (cond ((pair? x) | |
1100 | (cons (rebuild-macro-output (car x) m) | |
1101 | (rebuild-macro-output (cdr x) m))) | |
1102 | ((syntax-object? x) | |
1103 | (let ((w (syntax-object-wrap x))) | |
1104 | (let ((ms (wrap-marks w)) (s (wrap-subst w))) | |
1105 | (make-syntax-object (syntax-object-expression x) | |
1106 | (if (and (pair? ms) (eq? (car ms) the-anti-mark)) | |
1107 | (make-wrap (cdr ms) | |
1108 | (if rib (cons rib (cdr s)) (cdr s))) | |
1109 | (make-wrap (cons m ms) | |
1110 | (if rib | |
1111 | (cons rib (cons 'shift s)) | |
1112 | (cons 'shift s)))))))) | |
1113 | ((vector? x) | |
1114 | (let* ((n (vector-length x)) (v (make-vector n))) | |
1115 | (do ((i 0 (fx+ i 1))) | |
1116 | ((fx= i n) v) | |
1117 | (vector-set! v i | |
1118 | (rebuild-macro-output (vector-ref x i) m))))) | |
1119 | ((symbol? x) | |
1120 | (syntax-error x "encountered raw symbol in macro output")) | |
1121 | (else x)))) | |
1122 | (rebuild-macro-output (p (wrap e (anti-mark w))) (new-mark)))) | |
1123 | ||
1124 | (define chi-body | |
1125 | ;; In processing the forms of the body, we create a new, empty wrap. | |
1126 | ;; This wrap is augmented (destructively) each time we discover that | |
1127 | ;; the next form is a definition. This is done: | |
1128 | ;; | |
1129 | ;; (1) to allow the first nondefinition form to be a call to | |
1130 | ;; one of the defined ids even if the id previously denoted a | |
1131 | ;; definition keyword or keyword for a macro expanding into a | |
1132 | ;; definition; | |
1133 | ;; (2) to prevent subsequent definition forms (but unfortunately | |
1134 | ;; not earlier ones) and the first nondefinition form from | |
1135 | ;; confusing one of the bound identifiers for an auxiliary | |
1136 | ;; keyword; and | |
1137 | ;; (3) so that we do not need to restart the expansion of the | |
1138 | ;; first nondefinition form, which is problematic anyway | |
1139 | ;; since it might be the first element of a begin that we | |
1140 | ;; have just spliced into the body (meaning if we restarted, | |
1141 | ;; we'd really need to restart with the begin or the macro | |
1142 | ;; call that expanded into the begin, and we'd have to give | |
1143 | ;; up allowing (begin <defn>+ <expr>+), which is itself | |
1144 | ;; problematic since we don't know if a begin contains only | |
1145 | ;; definitions until we've expanded it). | |
1146 | ;; | |
1147 | ;; Before processing the body, we also create a new environment | |
1148 | ;; containing a placeholder for the bindings we will add later and | |
1149 | ;; associate this environment with each form. In processing a | |
1150 | ;; let-syntax or letrec-syntax, the associated environment may be | |
1151 | ;; augmented with local keyword bindings, so the environment may | |
1152 | ;; be different for different forms in the body. Once we have | |
1153 | ;; gathered up all of the definitions, we evaluate the transformer | |
1154 | ;; expressions and splice into r at the placeholder the new variable | |
1155 | ;; and keyword bindings. This allows let-syntax or letrec-syntax | |
1156 | ;; forms local to a portion or all of the body to shadow the | |
1157 | ;; definition bindings. | |
1158 | ;; | |
1159 | ;; Subforms of a begin, let-syntax, or letrec-syntax are spliced | |
1160 | ;; into the body. | |
1161 | ;; | |
1162 | ;; outer-form is fully wrapped w/source | |
1163 | (lambda (body outer-form r w) | |
1164 | (let* ((r (cons '("placeholder" . (placeholder)) r)) | |
1165 | (ribcage (make-empty-ribcage)) | |
1166 | (w (make-wrap (wrap-marks w) (cons ribcage (wrap-subst w))))) | |
1167 | (let parse ((body (map (lambda (x) (cons r (wrap x w))) body)) | |
1168 | (ids '()) (labels '()) (vars '()) (vals '()) (bindings '())) | |
1169 | (if (null? body) | |
1170 | (syntax-error outer-form "no expressions in body") | |
1171 | (let ((e (cdar body)) (er (caar body))) | |
1172 | (call-with-values | |
1173 | (lambda () (syntax-type e er empty-wrap no-source ribcage)) | |
1174 | (lambda (type value e w s) | |
1175 | (case type | |
1176 | ((define-form) | |
1177 | (let ((id (wrap value w)) (label (gen-label))) | |
1178 | (let ((var (gen-var id))) | |
1179 | (extend-ribcage! ribcage id label) | |
1180 | (parse (cdr body) | |
1181 | (cons id ids) (cons label labels) | |
1182 | (cons var vars) (cons (cons er (wrap e w)) vals) | |
1183 | (cons (make-binding 'lexical var) bindings))))) | |
1184 | ((define-syntax-form) | |
1185 | (let ((id (wrap value w)) (label (gen-label))) | |
1186 | (extend-ribcage! ribcage id label) | |
1187 | (parse (cdr body) | |
1188 | (cons id ids) (cons label labels) | |
1189 | vars vals | |
1190 | (cons (make-binding 'macro (cons er (wrap e w))) | |
1191 | bindings)))) | |
1192 | ((begin-form) | |
1193 | (syntax-case e () | |
1194 | ((_ e1 ...) | |
1195 | (parse (let f ((forms (syntax (e1 ...)))) | |
1196 | (if (null? forms) | |
1197 | (cdr body) | |
1198 | (cons (cons er (wrap (car forms) w)) | |
1199 | (f (cdr forms))))) | |
1200 | ids labels vars vals bindings)))) | |
1201 | ((local-syntax-form) | |
1202 | (chi-local-syntax value e er w s | |
1203 | (lambda (forms er w s) | |
1204 | (parse (let f ((forms forms)) | |
1205 | (if (null? forms) | |
1206 | (cdr body) | |
1207 | (cons (cons er (wrap (car forms) w)) | |
1208 | (f (cdr forms))))) | |
1209 | ids labels vars vals bindings)))) | |
1210 | (else ; found a non-definition | |
1211 | (if (null? ids) | |
1212 | (build-sequence no-source | |
1213 | (map (lambda (x) | |
1214 | (chi (cdr x) (car x) empty-wrap)) | |
1215 | (cons (cons er (source-wrap e w s)) | |
1216 | (cdr body)))) | |
1217 | (begin | |
1218 | (if (not (valid-bound-ids? ids)) | |
1219 | (syntax-error outer-form | |
1220 | "invalid or duplicate identifier in definition")) | |
1221 | (let loop ((bs bindings) (er-cache #f) (r-cache #f)) | |
1222 | (if (not (null? bs)) | |
1223 | (let* ((b (car bs))) | |
1224 | (if (eq? (car b) 'macro) | |
1225 | (let* ((er (cadr b)) | |
1226 | (r-cache | |
1227 | (if (eq? er er-cache) | |
1228 | r-cache | |
1229 | (macros-only-env er)))) | |
1230 | (set-cdr! b | |
1231 | (eval-local-transformer | |
1232 | (chi (cddr b) r-cache empty-wrap))) | |
1233 | (loop (cdr bs) er r-cache)) | |
1234 | (loop (cdr bs) er-cache r-cache))))) | |
1235 | (set-cdr! r (extend-env labels bindings (cdr r))) | |
1236 | (build-letrec no-source | |
1237 | vars | |
1238 | (map (lambda (x) | |
1239 | (chi (cdr x) (car x) empty-wrap)) | |
1240 | vals) | |
1241 | (build-sequence no-source | |
1242 | (map (lambda (x) | |
1243 | (chi (cdr x) (car x) empty-wrap)) | |
1244 | (cons (cons er (source-wrap e w s)) | |
1245 | (cdr body))))))))))))))))) | |
1246 | ||
1247 | (define chi-lambda-clause | |
1248 | (lambda (e c r w k) | |
1249 | (syntax-case c () | |
1250 | (((id ...) e1 e2 ...) | |
1251 | (let ((ids (syntax (id ...)))) | |
1252 | (if (not (valid-bound-ids? ids)) | |
1253 | (syntax-error e "invalid parameter list in") | |
1254 | (let ((labels (gen-labels ids)) | |
1255 | (new-vars (map gen-var ids))) | |
1256 | (k new-vars | |
1257 | (chi-body (syntax (e1 e2 ...)) | |
1258 | e | |
1259 | (extend-var-env labels new-vars r) | |
1260 | (make-binding-wrap ids labels w))))))) | |
1261 | ((ids e1 e2 ...) | |
1262 | (let ((old-ids (lambda-var-list (syntax ids)))) | |
1263 | (if (not (valid-bound-ids? old-ids)) | |
1264 | (syntax-error e "invalid parameter list in") | |
1265 | (let ((labels (gen-labels old-ids)) | |
1266 | (new-vars (map gen-var old-ids))) | |
1267 | (k (let f ((ls1 (cdr new-vars)) (ls2 (car new-vars))) | |
1268 | (if (null? ls1) | |
1269 | ls2 | |
1270 | (f (cdr ls1) (cons (car ls1) ls2)))) | |
1271 | (chi-body (syntax (e1 e2 ...)) | |
1272 | e | |
1273 | (extend-var-env labels new-vars r) | |
1274 | (make-binding-wrap old-ids labels w))))))) | |
1275 | (_ (syntax-error e))))) | |
1276 | ||
1277 | (define chi-local-syntax | |
1278 | (lambda (rec? e r w s k) | |
1279 | (syntax-case e () | |
1280 | ((_ ((id val) ...) e1 e2 ...) | |
1281 | (let ((ids (syntax (id ...)))) | |
1282 | (if (not (valid-bound-ids? ids)) | |
1283 | (syntax-error e "duplicate bound keyword in") | |
1284 | (let ((labels (gen-labels ids))) | |
1285 | (let ((new-w (make-binding-wrap ids labels w))) | |
1286 | (k (syntax (e1 e2 ...)) | |
1287 | (extend-env | |
1288 | labels | |
1289 | (let ((w (if rec? new-w w)) | |
1290 | (trans-r (macros-only-env r))) | |
1291 | (map (lambda (x) | |
1292 | (make-binding 'macro | |
1293 | (eval-local-transformer (chi x trans-r w)))) | |
1294 | (syntax (val ...)))) | |
1295 | r) | |
1296 | new-w | |
1297 | s)))))) | |
1298 | (_ (syntax-error (source-wrap e w s)))))) | |
1299 | ||
1300 | (define eval-local-transformer | |
1301 | (lambda (expanded) | |
1302 | (let ((p (local-eval-hook expanded))) | |
1303 | (if (procedure? p) | |
1304 | p | |
1305 | (syntax-error p "nonprocedure transfomer"))))) | |
1306 | ||
1307 | (define chi-void | |
1308 | (lambda () | |
1309 | (build-application no-source (build-primref no-source 'void) '()))) | |
1310 | ||
1311 | (define ellipsis? | |
1312 | (lambda (x) | |
1313 | (and (nonsymbol-id? x) | |
1314 | (free-id=? x (syntax (... ...)))))) | |
1315 | ||
1316 | ;;; data | |
1317 | ||
1318 | ;;; strips all annotations from potentially circular reader output | |
1319 | ||
1320 | (define strip-annotation | |
1321 | (lambda (x parent) | |
1322 | (cond | |
1323 | ((pair? x) | |
1324 | (let ((new (cons #f #f))) | |
1325 | (when parent (set-annotation-stripped! parent new)) | |
1326 | (set-car! new (strip-annotation (car x) #f)) | |
1327 | (set-cdr! new (strip-annotation (cdr x) #f)) | |
1328 | new)) | |
1329 | ((annotation? x) | |
1330 | (or (annotation-stripped x) | |
1331 | (strip-annotation (annotation-expression x) x))) | |
1332 | ((vector? x) | |
1333 | (let ((new (make-vector (vector-length x)))) | |
1334 | (when parent (set-annotation-stripped! parent new)) | |
1335 | (let loop ((i (- (vector-length x) 1))) | |
1336 | (unless (fx< i 0) | |
1337 | (vector-set! new i (strip-annotation (vector-ref x i) #f)) | |
1338 | (loop (fx- i 1)))) | |
1339 | new)) | |
1340 | (else x)))) | |
1341 | ||
1342 | ;;; strips syntax-objects down to top-wrap; if top-wrap is layered directly | |
1343 | ;;; on an annotation, strips the annotation as well. | |
1344 | ;;; since only the head of a list is annotated by the reader, not each pair | |
1345 | ;;; in the spine, we also check for pairs whose cars are annotated in case | |
1346 | ;;; we've been passed the cdr of an annotated list | |
1347 | ||
1348 | (define strip | |
1349 | (lambda (x w) | |
1350 | (if (top-marked? w) | |
1351 | (if (or (annotation? x) (and (pair? x) (annotation? (car x)))) | |
1352 | (strip-annotation x #f) | |
1353 | x) | |
1354 | (let f ((x x)) | |
1355 | (cond | |
1356 | ((syntax-object? x) | |
1357 | (strip (syntax-object-expression x) (syntax-object-wrap x))) | |
1358 | ((pair? x) | |
1359 | (let ((a (f (car x))) (d (f (cdr x)))) | |
1360 | (if (and (eq? a (car x)) (eq? d (cdr x))) | |
1361 | x | |
1362 | (cons a d)))) | |
1363 | ((vector? x) | |
1364 | (let ((old (vector->list x))) | |
1365 | (let ((new (map f old))) | |
1366 | (if (andmap eq? old new) x (list->vector new))))) | |
1367 | (else x)))))) | |
1368 | ||
1369 | ;;; lexical variables | |
1370 | ||
1371 | (define gen-var | |
1372 | (lambda (id) | |
1373 | (let ((id (if (syntax-object? id) (syntax-object-expression id) id))) | |
1374 | (if (annotation? id) | |
1375 | (build-lexical-var (annotation-source id) (annotation-expression id)) | |
1376 | (build-lexical-var no-source id))))) | |
1377 | ||
1378 | (define lambda-var-list | |
1379 | (lambda (vars) | |
1380 | (let lvl ((vars vars) (ls '()) (w empty-wrap)) | |
1381 | (cond | |
1382 | ((pair? vars) (lvl (cdr vars) (cons (wrap (car vars) w) ls) w)) | |
1383 | ((id? vars) (cons (wrap vars w) ls)) | |
1384 | ((null? vars) ls) | |
1385 | ((syntax-object? vars) | |
1386 | (lvl (syntax-object-expression vars) | |
1387 | ls | |
1388 | (join-wraps w (syntax-object-wrap vars)))) | |
1389 | ((annotation? vars) | |
1390 | (lvl (annotation-expression vars) ls w)) | |
1391 | ; include anything else to be caught by subsequent error | |
1392 | ; checking | |
1393 | (else (cons vars ls)))))) | |
1394 | ||
1395 | ;;; core transformers | |
1396 | ||
1397 | (global-extend 'local-syntax 'letrec-syntax #t) | |
1398 | (global-extend 'local-syntax 'let-syntax #f) | |
1399 | ||
1400 | (global-extend 'core 'fluid-let-syntax | |
1401 | (lambda (e r w s) | |
1402 | (syntax-case e () | |
1403 | ((_ ((var val) ...) e1 e2 ...) | |
1404 | (valid-bound-ids? (syntax (var ...))) | |
1405 | (let ((names (map (lambda (x) (id-var-name x w)) (syntax (var ...))))) | |
1406 | (for-each | |
1407 | (lambda (id n) | |
1408 | (case (binding-type (lookup n r)) | |
1409 | ((displaced-lexical) | |
1410 | (syntax-error (source-wrap id w s) | |
1411 | "identifier out of context")))) | |
1412 | (syntax (var ...)) | |
1413 | names) | |
1414 | (chi-body | |
1415 | (syntax (e1 e2 ...)) | |
1416 | (source-wrap e w s) | |
1417 | (extend-env | |
1418 | names | |
1419 | (let ((trans-r (macros-only-env r))) | |
1420 | (map (lambda (x) | |
1421 | (make-binding 'macro | |
1422 | (eval-local-transformer (chi x trans-r w)))) | |
1423 | (syntax (val ...)))) | |
1424 | r) | |
1425 | w))) | |
1426 | (_ (syntax-error (source-wrap e w s)))))) | |
1427 | ||
1428 | (global-extend 'core 'quote | |
1429 | (lambda (e r w s) | |
1430 | (syntax-case e () | |
1431 | ((_ e) (build-data s (strip (syntax e) w))) | |
1432 | (_ (syntax-error (source-wrap e w s)))))) | |
1433 | ||
1434 | (global-extend 'core 'syntax | |
1435 | (let () | |
1436 | (define gen-syntax | |
1437 | (lambda (src e r maps ellipsis?) | |
1438 | (if (id? e) | |
1439 | (let ((label (id-var-name e empty-wrap))) | |
1440 | (let ((b (lookup label r))) | |
1441 | (if (eq? (binding-type b) 'syntax) | |
1442 | (call-with-values | |
1443 | (lambda () | |
1444 | (let ((var.lev (binding-value b))) | |
1445 | (gen-ref src (car var.lev) (cdr var.lev) maps))) | |
1446 | (lambda (var maps) (values `(ref ,var) maps))) | |
1447 | (if (ellipsis? e) | |
1448 | (syntax-error src "misplaced ellipsis in syntax form") | |
1449 | (values `(quote ,e) maps))))) | |
1450 | (syntax-case e () | |
1451 | ((dots e) | |
1452 | (ellipsis? (syntax dots)) | |
1453 | (gen-syntax src (syntax e) r maps (lambda (x) #f))) | |
1454 | ((x dots . y) | |
1455 | ; this could be about a dozen lines of code, except that we | |
1456 | ; choose to handle (syntax (x ... ...)) forms | |
1457 | (ellipsis? (syntax dots)) | |
1458 | (let f ((y (syntax y)) | |
1459 | (k (lambda (maps) | |
1460 | (call-with-values | |
1461 | (lambda () | |
1462 | (gen-syntax src (syntax x) r | |
1463 | (cons '() maps) ellipsis?)) | |
1464 | (lambda (x maps) | |
1465 | (if (null? (car maps)) | |
1466 | (syntax-error src | |
1467 | "extra ellipsis in syntax form") | |
1468 | (values (gen-map x (car maps)) | |
1469 | (cdr maps)))))))) | |
1470 | (syntax-case y () | |
1471 | ((dots . y) | |
1472 | (ellipsis? (syntax dots)) | |
1473 | (f (syntax y) | |
1474 | (lambda (maps) | |
1475 | (call-with-values | |
1476 | (lambda () (k (cons '() maps))) | |
1477 | (lambda (x maps) | |
1478 | (if (null? (car maps)) | |
1479 | (syntax-error src | |
1480 | "extra ellipsis in syntax form") | |
1481 | (values (gen-mappend x (car maps)) | |
1482 | (cdr maps)))))))) | |
1483 | (_ (call-with-values | |
1484 | (lambda () (gen-syntax src y r maps ellipsis?)) | |
1485 | (lambda (y maps) | |
1486 | (call-with-values | |
1487 | (lambda () (k maps)) | |
1488 | (lambda (x maps) | |
1489 | (values (gen-append x y) maps))))))))) | |
1490 | ((x . y) | |
1491 | (call-with-values | |
1492 | (lambda () (gen-syntax src (syntax x) r maps ellipsis?)) | |
1493 | (lambda (x maps) | |
1494 | (call-with-values | |
1495 | (lambda () (gen-syntax src (syntax y) r maps ellipsis?)) | |
1496 | (lambda (y maps) (values (gen-cons x y) maps)))))) | |
1497 | (#(e1 e2 ...) | |
1498 | (call-with-values | |
1499 | (lambda () | |
1500 | (gen-syntax src (syntax (e1 e2 ...)) r maps ellipsis?)) | |
1501 | (lambda (e maps) (values (gen-vector e) maps)))) | |
1502 | (_ (values `(quote ,e) maps)))))) | |
1503 | ||
1504 | (define gen-ref | |
1505 | (lambda (src var level maps) | |
1506 | (if (fx= level 0) | |
1507 | (values var maps) | |
1508 | (if (null? maps) | |
1509 | (syntax-error src "missing ellipsis in syntax form") | |
1510 | (call-with-values | |
1511 | (lambda () (gen-ref src var (fx- level 1) (cdr maps))) | |
1512 | (lambda (outer-var outer-maps) | |
1513 | (let ((b (assq outer-var (car maps)))) | |
1514 | (if b | |
1515 | (values (cdr b) maps) | |
1516 | (let ((inner-var (gen-var 'tmp))) | |
1517 | (values inner-var | |
1518 | (cons (cons (cons outer-var inner-var) | |
1519 | (car maps)) | |
1520 | outer-maps))))))))))) | |
1521 | ||
1522 | (define gen-mappend | |
1523 | (lambda (e map-env) | |
1524 | `(apply (primitive append) ,(gen-map e map-env)))) | |
1525 | ||
1526 | (define gen-map | |
1527 | (lambda (e map-env) | |
1528 | (let ((formals (map cdr map-env)) | |
1529 | (actuals (map (lambda (x) `(ref ,(car x))) map-env))) | |
1530 | (cond | |
1531 | ((eq? (car e) 'ref) | |
1532 | ; identity map equivalence: | |
1533 | ; (map (lambda (x) x) y) == y | |
1534 | (car actuals)) | |
1535 | ((andmap | |
1536 | (lambda (x) (and (eq? (car x) 'ref) (memq (cadr x) formals))) | |
1537 | (cdr e)) | |
1538 | ; eta map equivalence: | |
1539 | ; (map (lambda (x ...) (f x ...)) y ...) == (map f y ...) | |
1540 | `(map (primitive ,(car e)) | |
1541 | ,@(map (let ((r (map cons formals actuals))) | |
1542 | (lambda (x) (cdr (assq (cadr x) r)))) | |
1543 | (cdr e)))) | |
1544 | (else `(map (lambda ,formals ,e) ,@actuals)))))) | |
1545 | ||
1546 | (define gen-cons | |
1547 | (lambda (x y) | |
1548 | (case (car y) | |
1549 | ((quote) | |
1550 | (if (eq? (car x) 'quote) | |
1551 | `(quote (,(cadr x) . ,(cadr y))) | |
1552 | (if (eq? (cadr y) '()) | |
1553 | `(list ,x) | |
1554 | `(cons ,x ,y)))) | |
1555 | ((list) `(list ,x ,@(cdr y))) | |
1556 | (else `(cons ,x ,y))))) | |
1557 | ||
1558 | (define gen-append | |
1559 | (lambda (x y) | |
1560 | (if (equal? y '(quote ())) | |
1561 | x | |
1562 | `(append ,x ,y)))) | |
1563 | ||
1564 | (define gen-vector | |
1565 | (lambda (x) | |
1566 | (cond | |
1567 | ((eq? (car x) 'list) `(vector ,@(cdr x))) | |
1568 | ((eq? (car x) 'quote) `(quote #(,@(cadr x)))) | |
1569 | (else `(list->vector ,x))))) | |
1570 | ||
1571 | ||
1572 | (define regen | |
1573 | (lambda (x) | |
1574 | (case (car x) | |
1575 | ((ref) (build-lexical-reference 'value no-source (cadr x))) | |
1576 | ((primitive) (build-primref no-source (cadr x))) | |
1577 | ((quote) (build-data no-source (cadr x))) | |
1578 | ((lambda) (build-lambda no-source (cadr x) (regen (caddr x)))) | |
1579 | ((map) (let ((ls (map regen (cdr x)))) | |
1580 | (build-application no-source | |
1581 | (if (fx= (length ls) 2) | |
1582 | (build-primref no-source 'map) | |
1583 | ; really need to do our own checking here | |
1584 | (build-primref no-source 2 'map)) ; require error check | |
1585 | ls))) | |
1586 | (else (build-application no-source | |
1587 | (build-primref no-source (car x)) | |
1588 | (map regen (cdr x))))))) | |
1589 | ||
1590 | (lambda (e r w s) | |
1591 | (let ((e (source-wrap e w s))) | |
1592 | (syntax-case e () | |
1593 | ((_ x) | |
1594 | (call-with-values | |
1595 | (lambda () (gen-syntax e (syntax x) r '() ellipsis?)) | |
1596 | (lambda (e maps) (regen e)))) | |
1597 | (_ (syntax-error e))))))) | |
1598 | ||
1599 | ||
1600 | (global-extend 'core 'lambda | |
1601 | (lambda (e r w s) | |
1602 | (syntax-case e () | |
1603 | ((_ . c) | |
1604 | (chi-lambda-clause (source-wrap e w s) (syntax c) r w | |
1605 | (lambda (vars body) (build-lambda s vars body))))))) | |
1606 | ||
1607 | ||
1608 | (global-extend 'core 'let | |
1609 | (let () | |
1610 | (define (chi-let e r w s constructor ids vals exps) | |
1611 | (if (not (valid-bound-ids? ids)) | |
1612 | (syntax-error e "duplicate bound variable in") | |
1613 | (let ((labels (gen-labels ids)) | |
1614 | (new-vars (map gen-var ids))) | |
1615 | (let ((nw (make-binding-wrap ids labels w)) | |
1616 | (nr (extend-var-env labels new-vars r))) | |
1617 | (constructor s | |
1618 | new-vars | |
1619 | (map (lambda (x) (chi x r w)) vals) | |
1620 | (chi-body exps (source-wrap e nw s) nr nw)))))) | |
1621 | (lambda (e r w s) | |
1622 | (syntax-case e () | |
1623 | ((_ ((id val) ...) e1 e2 ...) | |
1624 | (chi-let e r w s | |
1625 | build-let | |
1626 | (syntax (id ...)) | |
1627 | (syntax (val ...)) | |
1628 | (syntax (e1 e2 ...)))) | |
1629 | ((_ f ((id val) ...) e1 e2 ...) | |
1630 | (id? (syntax f)) | |
1631 | (chi-let e r w s | |
1632 | build-named-let | |
1633 | (syntax (f id ...)) | |
1634 | (syntax (val ...)) | |
1635 | (syntax (e1 e2 ...)))) | |
1636 | (_ (syntax-error (source-wrap e w s))))))) | |
1637 | ||
1638 | ||
1639 | (global-extend 'core 'letrec | |
1640 | (lambda (e r w s) | |
1641 | (syntax-case e () | |
1642 | ((_ ((id val) ...) e1 e2 ...) | |
1643 | (let ((ids (syntax (id ...)))) | |
1644 | (if (not (valid-bound-ids? ids)) | |
1645 | (syntax-error e "duplicate bound variable in") | |
1646 | (let ((labels (gen-labels ids)) | |
1647 | (new-vars (map gen-var ids))) | |
1648 | (let ((w (make-binding-wrap ids labels w)) | |
1649 | (r (extend-var-env labels new-vars r))) | |
1650 | (build-letrec s | |
1651 | new-vars | |
1652 | (map (lambda (x) (chi x r w)) (syntax (val ...))) | |
1653 | (chi-body (syntax (e1 e2 ...)) (source-wrap e w s) r w))))))) | |
1654 | (_ (syntax-error (source-wrap e w s)))))) | |
1655 | ||
1656 | ||
1657 | (global-extend 'core 'set! | |
1658 | (lambda (e r w s) | |
1659 | (syntax-case e () | |
1660 | ((_ id val) | |
1661 | (id? (syntax id)) | |
1662 | (let ((val (chi (syntax val) r w)) | |
1663 | (n (id-var-name (syntax id) w))) | |
1664 | (let ((b (lookup n r))) | |
1665 | (case (binding-type b) | |
1666 | ((lexical) | |
1667 | (build-lexical-assignment s (binding-value b) val)) | |
1668 | ((global) (build-global-assignment s n val)) | |
1669 | ((displaced-lexical) | |
1670 | (syntax-error (wrap (syntax id) w) | |
1671 | "identifier out of context")) | |
1672 | (else (syntax-error (source-wrap e w s))))))) | |
1673 | (_ (syntax-error (source-wrap e w s)))))) | |
1674 | ||
1675 | (global-extend 'begin 'begin '()) | |
1676 | ||
1677 | (global-extend 'define 'define '()) | |
1678 | ||
1679 | (global-extend 'define-syntax 'define-syntax '()) | |
1680 | ||
1681 | (global-extend 'eval-when 'eval-when '()) | |
1682 | ||
1683 | (global-extend 'core 'syntax-case | |
1684 | (let () | |
1685 | (define convert-pattern | |
1686 | ; accepts pattern & keys | |
1687 | ; returns syntax-dispatch pattern & ids | |
1688 | (lambda (pattern keys) | |
1689 | (let cvt ((p pattern) (n 0) (ids '())) | |
1690 | (if (id? p) | |
1691 | (if (bound-id-member? p keys) | |
1692 | (values (vector 'free-id p) ids) | |
1693 | (values 'any (cons (cons p n) ids))) | |
1694 | (syntax-case p () | |
1695 | ((x dots) | |
1696 | (ellipsis? (syntax dots)) | |
1697 | (call-with-values | |
1698 | (lambda () (cvt (syntax x) (fx+ n 1) ids)) | |
1699 | (lambda (p ids) | |
1700 | (values (if (eq? p 'any) 'each-any (vector 'each p)) | |
1701 | ids)))) | |
1702 | ((x . y) | |
1703 | (call-with-values | |
1704 | (lambda () (cvt (syntax y) n ids)) | |
1705 | (lambda (y ids) | |
1706 | (call-with-values | |
1707 | (lambda () (cvt (syntax x) n ids)) | |
1708 | (lambda (x ids) | |
1709 | (values (cons x y) ids)))))) | |
1710 | (() (values '() ids)) | |
1711 | (#(x ...) | |
1712 | (call-with-values | |
1713 | (lambda () (cvt (syntax (x ...)) n ids)) | |
1714 | (lambda (p ids) (values (vector 'vector p) ids)))) | |
1715 | (x (values (vector 'atom (strip p empty-wrap)) ids))))))) | |
1716 | ||
1717 | (define build-dispatch-call | |
1718 | (lambda (pvars exp y r) | |
1719 | (let ((ids (map car pvars)) (levels (map cdr pvars))) | |
1720 | (let ((labels (gen-labels ids)) (new-vars (map gen-var ids))) | |
1721 | (build-application no-source | |
1722 | (build-primref no-source 'apply) | |
1723 | (list (build-lambda no-source new-vars | |
1724 | (chi exp | |
1725 | (extend-env | |
1726 | labels | |
1727 | (map (lambda (var level) | |
1728 | (make-binding 'syntax `(,var . ,level))) | |
1729 | new-vars | |
1730 | (map cdr pvars)) | |
1731 | r) | |
1732 | (make-binding-wrap ids labels empty-wrap))) | |
1733 | y)))))) | |
1734 | ||
1735 | (define gen-clause | |
1736 | (lambda (x keys clauses r pat fender exp) | |
1737 | (call-with-values | |
1738 | (lambda () (convert-pattern pat keys)) | |
1739 | (lambda (p pvars) | |
1740 | (cond | |
1741 | ((not (distinct-bound-ids? (map car pvars))) | |
1742 | (syntax-error pat | |
1743 | "duplicate pattern variable in syntax-case pattern")) | |
1744 | ((not (andmap (lambda (x) (not (ellipsis? (car x)))) pvars)) | |
1745 | (syntax-error pat | |
1746 | "misplaced ellipsis in syntax-case pattern")) | |
1747 | (else | |
1748 | (let ((y (gen-var 'tmp))) | |
1749 | ; fat finger binding and references to temp variable y | |
1750 | (build-application no-source | |
1751 | (build-lambda no-source (list y) | |
1752 | (let ((y (build-lexical-reference 'value no-source y))) | |
1753 | (build-conditional no-source | |
1754 | (syntax-case fender () | |
1755 | (#t y) | |
1756 | (_ (build-conditional no-source | |
1757 | y | |
1758 | (build-dispatch-call pvars fender y r) | |
1759 | (build-data no-source #f)))) | |
1760 | (build-dispatch-call pvars exp y r) | |
1761 | (gen-syntax-case x keys clauses r)))) | |
1762 | (list (if (eq? p 'any) | |
1763 | (build-application no-source | |
1764 | (build-primref no-source 'list) | |
1765 | (list x)) | |
1766 | (build-application no-source | |
1767 | (build-primref no-source 'syntax-dispatch) | |
1768 | (list x (build-data no-source p))))))))))))) | |
1769 | ||
1770 | (define gen-syntax-case | |
1771 | (lambda (x keys clauses r) | |
1772 | (if (null? clauses) | |
1773 | (build-application no-source | |
1774 | (build-primref no-source 'syntax-error) | |
1775 | (list x)) | |
1776 | (syntax-case (car clauses) () | |
1777 | ((pat exp) | |
1778 | (if (and (id? (syntax pat)) | |
1779 | (andmap (lambda (x) (not (free-id=? (syntax pat) x))) | |
1780 | (cons (syntax (... ...)) keys))) | |
1781 | (let ((labels (list (gen-label))) | |
1782 | (var (gen-var (syntax pat)))) | |
1783 | (build-application no-source | |
1784 | (build-lambda no-source (list var) | |
1785 | (chi (syntax exp) | |
1786 | (extend-env labels | |
1787 | (list (make-binding 'syntax `(,var . 0))) | |
1788 | r) | |
1789 | (make-binding-wrap (syntax (pat)) | |
1790 | labels empty-wrap))) | |
1791 | (list x))) | |
1792 | (gen-clause x keys (cdr clauses) r | |
1793 | (syntax pat) #t (syntax exp)))) | |
1794 | ((pat fender exp) | |
1795 | (gen-clause x keys (cdr clauses) r | |
1796 | (syntax pat) (syntax fender) (syntax exp))) | |
1797 | (_ (syntax-error (car clauses) "invalid syntax-case clause")))))) | |
1798 | ||
1799 | (lambda (e r w s) | |
1800 | (let ((e (source-wrap e w s))) | |
1801 | (syntax-case e () | |
1802 | ((_ val (key ...) m ...) | |
1803 | (if (andmap (lambda (x) (and (id? x) (not (ellipsis? x)))) | |
1804 | (syntax (key ...))) | |
1805 | (let ((x (gen-var 'tmp))) | |
1806 | ; fat finger binding and references to temp variable x | |
1807 | (build-application s | |
1808 | (build-lambda no-source (list x) | |
1809 | (gen-syntax-case (build-lexical-reference 'value no-source x) | |
1810 | (syntax (key ...)) (syntax (m ...)) | |
1811 | r)) | |
1812 | (list (chi (syntax val) r empty-wrap)))) | |
1813 | (syntax-error e "invalid literals list in")))))))) | |
1814 | ||
1815 | ;;; The portable sc-expand seeds chi-top's mode m with 'e (for | |
1816 | ;;; evaluating) and esew (which stands for "eval syntax expanders | |
1817 | ;;; when") with '(eval). In Chez Scheme, m is set to 'c instead of e | |
1818 | ;;; if we are compiling a file, and esew is set to | |
1819 | ;;; (eval-syntactic-expanders-when), which defaults to the list | |
1820 | ;;; '(compile load eval). This means that, by default, top-level | |
1821 | ;;; syntactic definitions are evaluated immediately after they are | |
1822 | ;;; expanded, and the expanded definitions are also residualized into | |
1823 | ;;; the object file if we are compiling a file. | |
1824 | (set! sc-expand | |
1825 | (let ((m 'e) (esew '(eval))) | |
1826 | (lambda (x) | |
1827 | (if (and (pair? x) (equal? (car x) noexpand)) | |
1828 | (cadr x) | |
1829 | (chi-top x null-env top-wrap m esew))))) | |
1830 | ||
1831 | (set! sc-expand3 | |
1832 | (let ((m 'e) (esew '(eval))) | |
1833 | (lambda (x . rest) | |
1834 | (if (and (pair? x) (equal? (car x) noexpand)) | |
1835 | (cadr x) | |
1836 | (chi-top x | |
1837 | null-env | |
1838 | top-wrap | |
1839 | (if (null? rest) m (car rest)) | |
1840 | (if (or (null? rest) (null? (cdr rest))) | |
1841 | esew | |
1842 | (cadr rest))))))) | |
1843 | ||
1844 | (set! identifier? | |
1845 | (lambda (x) | |
1846 | (nonsymbol-id? x))) | |
1847 | ||
1848 | (set! datum->syntax-object | |
1849 | (lambda (id datum) | |
1850 | (arg-check nonsymbol-id? id 'datum->syntax-object) | |
1851 | (make-syntax-object datum (syntax-object-wrap id)))) | |
1852 | ||
1853 | (set! syntax-object->datum | |
1854 | ; accepts any object, since syntax objects may consist partially | |
1855 | ; or entirely of unwrapped, nonsymbolic data | |
1856 | (lambda (x) | |
1857 | (strip x empty-wrap))) | |
1858 | ||
1859 | (set! generate-temporaries | |
1860 | (lambda (ls) | |
1861 | (arg-check list? ls 'generate-temporaries) | |
1862 | (map (lambda (x) (wrap (gensym-hook) top-wrap)) ls))) | |
1863 | ||
1864 | (set! free-identifier=? | |
1865 | (lambda (x y) | |
1866 | (arg-check nonsymbol-id? x 'free-identifier=?) | |
1867 | (arg-check nonsymbol-id? y 'free-identifier=?) | |
1868 | (free-id=? x y))) | |
1869 | ||
1870 | (set! bound-identifier=? | |
1871 | (lambda (x y) | |
1872 | (arg-check nonsymbol-id? x 'bound-identifier=?) | |
1873 | (arg-check nonsymbol-id? y 'bound-identifier=?) | |
1874 | (bound-id=? x y))) | |
1875 | ||
1876 | (set! syntax-error | |
1877 | (lambda (object . messages) | |
1878 | (for-each (lambda (x) (arg-check string? x 'syntax-error)) messages) | |
1879 | (let ((message (if (null? messages) | |
1880 | "invalid syntax" | |
1881 | (apply string-append messages)))) | |
1882 | (error-hook #f message (strip object empty-wrap))))) | |
1883 | ||
1884 | (set! install-global-transformer | |
1885 | (lambda (sym v) | |
1886 | (arg-check symbol? sym 'define-syntax) | |
1887 | (arg-check procedure? v 'define-syntax) | |
1888 | (global-extend 'macro sym v))) | |
1889 | ||
1890 | ;;; syntax-dispatch expects an expression and a pattern. If the expression | |
1891 | ;;; matches the pattern a list of the matching expressions for each | |
1892 | ;;; "any" is returned. Otherwise, #f is returned. (This use of #f will | |
1893 | ;;; not work on r4rs implementations that violate the ieee requirement | |
1894 | ;;; that #f and () be distinct.) | |
1895 | ||
1896 | ;;; The expression is matched with the pattern as follows: | |
1897 | ||
1898 | ;;; pattern: matches: | |
1899 | ;;; () empty list | |
1900 | ;;; any anything | |
1901 | ;;; (<pattern>1 . <pattern>2) (<pattern>1 . <pattern>2) | |
1902 | ;;; each-any (any*) | |
1903 | ;;; #(free-id <key>) <key> with free-identifier=? | |
1904 | ;;; #(each <pattern>) (<pattern>*) | |
1905 | ;;; #(vector <pattern>) (list->vector <pattern>) | |
1906 | ;;; #(atom <object>) <object> with "equal?" | |
1907 | ||
1908 | ;;; Vector cops out to pair under assumption that vectors are rare. If | |
1909 | ;;; not, should convert to: | |
1910 | ;;; #(vector <pattern>*) #(<pattern>*) | |
1911 | ||
1912 | (let () | |
1913 | ||
1914 | (define match-each | |
1915 | (lambda (e p w) | |
1916 | (cond | |
1917 | ((annotation? e) | |
1918 | (match-each (annotation-expression e) p w)) | |
1919 | ((pair? e) | |
1920 | (let ((first (match (car e) p w '()))) | |
1921 | (and first | |
1922 | (let ((rest (match-each (cdr e) p w))) | |
1923 | (and rest (cons first rest)))))) | |
1924 | ((null? e) '()) | |
1925 | ((syntax-object? e) | |
1926 | (match-each (syntax-object-expression e) | |
1927 | p | |
1928 | (join-wraps w (syntax-object-wrap e)))) | |
1929 | (else #f)))) | |
1930 | ||
1931 | (define match-each-any | |
1932 | (lambda (e w) | |
1933 | (cond | |
1934 | ((annotation? e) | |
1935 | (match-each-any (annotation-expression e) w)) | |
1936 | ((pair? e) | |
1937 | (let ((l (match-each-any (cdr e) w))) | |
1938 | (and l (cons (wrap (car e) w) l)))) | |
1939 | ((null? e) '()) | |
1940 | ((syntax-object? e) | |
1941 | (match-each-any (syntax-object-expression e) | |
1942 | (join-wraps w (syntax-object-wrap e)))) | |
1943 | (else #f)))) | |
1944 | ||
1945 | (define match-empty | |
1946 | (lambda (p r) | |
1947 | (cond | |
1948 | ((null? p) r) | |
1949 | ((eq? p 'any) (cons '() r)) | |
1950 | ((pair? p) (match-empty (car p) (match-empty (cdr p) r))) | |
1951 | ((eq? p 'each-any) (cons '() r)) | |
1952 | (else | |
1953 | (case (vector-ref p 0) | |
1954 | ((each) (match-empty (vector-ref p 1) r)) | |
1955 | ((free-id atom) r) | |
1956 | ((vector) (match-empty (vector-ref p 1) r))))))) | |
1957 | ||
1958 | (define match* | |
1959 | (lambda (e p w r) | |
1960 | (cond | |
1961 | ((null? p) (and (null? e) r)) | |
1962 | ((pair? p) | |
1963 | (and (pair? e) (match (car e) (car p) w | |
1964 | (match (cdr e) (cdr p) w r)))) | |
1965 | ((eq? p 'each-any) | |
1966 | (let ((l (match-each-any e w))) (and l (cons l r)))) | |
1967 | (else | |
1968 | (case (vector-ref p 0) | |
1969 | ((each) | |
1970 | (if (null? e) | |
1971 | (match-empty (vector-ref p 1) r) | |
1972 | (let ((l (match-each e (vector-ref p 1) w))) | |
1973 | (and l | |
1974 | (let collect ((l l)) | |
1975 | (if (null? (car l)) | |
1976 | r | |
1977 | (cons (map car l) (collect (map cdr l))))))))) | |
1978 | ((free-id) (and (id? e) (free-id=? (wrap e w) (vector-ref p 1)) r)) | |
1979 | ((atom) (and (equal? (vector-ref p 1) (strip e w)) r)) | |
1980 | ((vector) | |
1981 | (and (vector? e) | |
1982 | (match (vector->list e) (vector-ref p 1) w r)))))))) | |
1983 | ||
1984 | (define match | |
1985 | (lambda (e p w r) | |
1986 | (cond | |
1987 | ((not r) #f) | |
1988 | ((eq? p 'any) (cons (wrap e w) r)) | |
1989 | ((syntax-object? e) | |
1990 | (match* | |
1991 | (unannotate (syntax-object-expression e)) | |
1992 | p | |
1993 | (join-wraps w (syntax-object-wrap e)) | |
1994 | r)) | |
1995 | (else (match* (unannotate e) p w r))))) | |
1996 | ||
1997 | (set! syntax-dispatch | |
1998 | (lambda (e p) | |
1999 | (cond | |
2000 | ((eq? p 'any) (list e)) | |
2001 | ((syntax-object? e) | |
2002 | (match* (unannotate (syntax-object-expression e)) | |
2003 | p (syntax-object-wrap e) '())) | |
2004 | (else (match* (unannotate e) p empty-wrap '()))))) | |
2005 | )) | |
2006 | ) | |
2007 | ||
2008 | (define-syntax with-syntax | |
2009 | (lambda (x) | |
2010 | (syntax-case x () | |
2011 | ((_ () e1 e2 ...) | |
2012 | (syntax (begin e1 e2 ...))) | |
2013 | ((_ ((out in)) e1 e2 ...) | |
2014 | (syntax (syntax-case in () (out (begin e1 e2 ...))))) | |
2015 | ((_ ((out in) ...) e1 e2 ...) | |
2016 | (syntax (syntax-case (list in ...) () | |
2017 | ((out ...) (begin e1 e2 ...)))))))) | |
2018 | ||
2019 | (define-syntax syntax-rules | |
2020 | (lambda (x) | |
2021 | (syntax-case x () | |
2022 | ((_ (k ...) ((keyword . pattern) template) ...) | |
2023 | (syntax (lambda (x) | |
2024 | (syntax-case x (k ...) | |
2025 | ((dummy . pattern) (syntax template)) | |
2026 | ...))))))) | |
2027 | ||
2028 | (define-syntax let* | |
2029 | (lambda (x) | |
2030 | (syntax-case x () | |
2031 | ((let* ((x v) ...) e1 e2 ...) | |
2032 | (andmap identifier? (syntax (x ...))) | |
2033 | (let f ((bindings (syntax ((x v) ...)))) | |
2034 | (if (null? bindings) | |
2035 | (syntax (let () e1 e2 ...)) | |
2036 | (with-syntax ((body (f (cdr bindings))) | |
2037 | (binding (car bindings))) | |
2038 | (syntax (let (binding) body))))))))) | |
2039 | ||
2040 | (define-syntax do | |
2041 | (lambda (orig-x) | |
2042 | (syntax-case orig-x () | |
2043 | ((_ ((var init . step) ...) (e0 e1 ...) c ...) | |
2044 | (with-syntax (((step ...) | |
2045 | (map (lambda (v s) | |
2046 | (syntax-case s () | |
2047 | (() v) | |
2048 | ((e) (syntax e)) | |
2049 | (_ (syntax-error orig-x)))) | |
2050 | (syntax (var ...)) | |
2051 | (syntax (step ...))))) | |
2052 | (syntax-case (syntax (e1 ...)) () | |
2053 | (() (syntax (let doloop ((var init) ...) | |
2054 | (if (not e0) | |
2055 | (begin c ... (doloop step ...)))))) | |
2056 | ((e1 e2 ...) | |
2057 | (syntax (let doloop ((var init) ...) | |
2058 | (if e0 | |
2059 | (begin e1 e2 ...) | |
2060 | (begin c ... (doloop step ...)))))))))))) | |
2061 | ||
2062 | (define-syntax quasiquote | |
2063 | (letrec | |
2064 | ((quasicons | |
2065 | (lambda (x y) | |
2066 | (with-syntax ((x x) (y y)) | |
2067 | (syntax-case (syntax y) (quote list) | |
2068 | ((quote dy) | |
2069 | (syntax-case (syntax x) (quote) | |
2070 | ((quote dx) (syntax (quote (dx . dy)))) | |
2071 | (_ (if (null? (syntax dy)) | |
2072 | (syntax (list x)) | |
2073 | (syntax (cons x y)))))) | |
2074 | ((list . stuff) (syntax (list x . stuff))) | |
2075 | (else (syntax (cons x y))))))) | |
2076 | (quasiappend | |
2077 | (lambda (x y) | |
2078 | (with-syntax ((x x) (y y)) | |
2079 | (syntax-case (syntax y) (quote) | |
2080 | ((quote ()) (syntax x)) | |
2081 | (_ (syntax (append x y))))))) | |
2082 | (quasivector | |
2083 | (lambda (x) | |
2084 | (with-syntax ((x x)) | |
2085 | (syntax-case (syntax x) (quote list) | |
2086 | ((quote (x ...)) (syntax (quote #(x ...)))) | |
2087 | ((list x ...) (syntax (vector x ...))) | |
2088 | (_ (syntax (list->vector x))))))) | |
2089 | (quasi | |
2090 | (lambda (p lev) | |
2091 | (syntax-case p (unquote unquote-splicing quasiquote) | |
2092 | ((unquote p) | |
2093 | (if (= lev 0) | |
2094 | (syntax p) | |
2095 | (quasicons (syntax (quote unquote)) | |
2096 | (quasi (syntax (p)) (- lev 1))))) | |
2097 | (((unquote-splicing p) . q) | |
2098 | (if (= lev 0) | |
2099 | (quasiappend (syntax p) (quasi (syntax q) lev)) | |
2100 | (quasicons (quasicons (syntax (quote unquote-splicing)) | |
2101 | (quasi (syntax (p)) (- lev 1))) | |
2102 | (quasi (syntax q) lev)))) | |
2103 | ((quasiquote p) | |
2104 | (quasicons (syntax (quote quasiquote)) | |
2105 | (quasi (syntax (p)) (+ lev 1)))) | |
2106 | ((p . q) | |
2107 | (quasicons (quasi (syntax p) lev) (quasi (syntax q) lev))) | |
2108 | (#(x ...) (quasivector (quasi (syntax (x ...)) lev))) | |
2109 | (p (syntax (quote p))))))) | |
2110 | (lambda (x) | |
2111 | (syntax-case x () | |
2112 | ((_ e) (quasi (syntax e) 0)))))) | |
2113 | ||
2114 | (define-syntax include | |
2115 | (lambda (x) | |
2116 | (define read-file | |
2117 | (lambda (fn k) | |
2118 | (let ((p (open-input-file fn))) | |
2119 | (let f ((x (read p))) | |
2120 | (if (eof-object? x) | |
2121 | (begin (close-input-port p) '()) | |
2122 | (cons (datum->syntax-object k x) | |
2123 | (f (read p)))))))) | |
2124 | (syntax-case x () | |
2125 | ((k filename) | |
2126 | (let ((fn (syntax-object->datum (syntax filename)))) | |
2127 | (with-syntax (((exp ...) (read-file fn (syntax k)))) | |
2128 | (syntax (begin exp ...)))))))) | |
2129 | ||
2130 | (define-syntax unquote | |
2131 | (lambda (x) | |
2132 | (syntax-case x () | |
2133 | ((_ e) | |
2134 | (error 'unquote | |
2135 | "expression ,~s not valid outside of quasiquote" | |
2136 | (syntax-object->datum (syntax e))))))) | |
2137 | ||
2138 | (define-syntax unquote-splicing | |
2139 | (lambda (x) | |
2140 | (syntax-case x () | |
2141 | ((_ e) | |
2142 | (error 'unquote-splicing | |
2143 | "expression ,@~s not valid outside of quasiquote" | |
2144 | (syntax-object->datum (syntax e))))))) | |
2145 | ||
2146 | (define-syntax case | |
2147 | (lambda (x) | |
2148 | (syntax-case x () | |
2149 | ((_ e m1 m2 ...) | |
2150 | (with-syntax | |
2151 | ((body (let f ((clause (syntax m1)) (clauses (syntax (m2 ...)))) | |
2152 | (if (null? clauses) | |
2153 | (syntax-case clause (else) | |
2154 | ((else e1 e2 ...) (syntax (begin e1 e2 ...))) | |
2155 | (((k ...) e1 e2 ...) | |
2156 | (syntax (if (memv t '(k ...)) (begin e1 e2 ...)))) | |
2157 | (_ (syntax-error x))) | |
2158 | (with-syntax ((rest (f (car clauses) (cdr clauses)))) | |
2159 | (syntax-case clause (else) | |
2160 | (((k ...) e1 e2 ...) | |
2161 | (syntax (if (memv t '(k ...)) | |
2162 | (begin e1 e2 ...) | |
2163 | rest))) | |
2164 | (_ (syntax-error x)))))))) | |
2165 | (syntax (let ((t e)) body))))))) | |
2166 | ||
2167 | (define-syntax identifier-syntax | |
2168 | (lambda (x) | |
2169 | (syntax-case x () | |
2170 | ((_ e) | |
2171 | (syntax | |
2172 | (lambda (x) | |
2173 | (syntax-case x () | |
2174 | (id | |
2175 | (identifier? (syntax id)) | |
2176 | (syntax e)) | |
2177 | ((_ x (... ...)) | |
2178 | (syntax (e x (... ...))))))))))) | |
2179 |