Commit | Line | Data |
---|---|---|
80b01fd0 AW |
1 | ;;; Continuation-passing style (CPS) intermediate language (IL) |
2 | ||
7ab76a83 | 3 | ;; Copyright (C) 2013, 2014 Free Software Foundation, Inc. |
80b01fd0 AW |
4 | |
5 | ;;;; This library is free software; you can redistribute it and/or | |
6 | ;;;; modify it under the terms of the GNU Lesser General Public | |
7 | ;;;; License as published by the Free Software Foundation; either | |
8 | ;;;; version 3 of the License, or (at your option) any later version. | |
9 | ;;;; | |
10 | ;;;; This library is distributed in the hope that it will be useful, | |
11 | ;;;; but WITHOUT ANY WARRANTY; without even the implied warranty of | |
12 | ;;;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU | |
13 | ;;;; Lesser General Public License for more details. | |
14 | ;;;; | |
15 | ;;;; You should have received a copy of the GNU Lesser General Public | |
16 | ;;;; License along with this library; if not, write to the Free Software | |
17 | ;;;; Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA | |
18 | ||
19 | ;;; Commentary: | |
20 | ;;; | |
21 | ;;; This is the continuation-passing style (CPS) intermediate language | |
22 | ;;; (IL) for Guile. | |
23 | ;;; | |
24 | ;;; There are two kinds of terms in CPS: terms that bind continuations, | |
25 | ;;; and terms that call continuations. | |
26 | ;;; | |
27 | ;;; $letk binds a set of mutually recursive continuations, each one an | |
6e422a35 AW |
28 | ;;; instance of $cont. A $cont declares the name of a continuation, and |
29 | ;;; then contains as a subterm the particular continuation instance: | |
30 | ;;; $kif for test continuations, $kargs for continuations that bind | |
31 | ;;; values, etc. | |
80b01fd0 AW |
32 | ;;; |
33 | ;;; $continue nodes call continuations. The expression contained in the | |
34 | ;;; $continue node determines the value or values that are passed to the | |
35 | ;;; target continuation: $const to pass a constant value, $values to | |
6e422a35 | 36 | ;;; pass multiple named values, etc. $continue nodes also record the source at which |
80b01fd0 AW |
37 | ;;; |
38 | ;;; Additionally there is $letrec, a term that binds mutually recursive | |
39 | ;;; functions. The contification pass will turn $letrec into $letk if | |
40 | ;;; it can do so. Otherwise, the closure conversion pass will desugar | |
41 | ;;; $letrec into an equivalent sequence of make-closure primcalls and | |
42 | ;;; subsequent initializations of the captured variables of the | |
43 | ;;; closures. You can think of $letrec as pertaining to "high CPS", | |
44 | ;;; whereas later passes will only see "low CPS", which does not have | |
45 | ;;; $letrec. | |
46 | ;;; | |
47 | ;;; This particular formulation of CPS was inspired by Andrew Kennedy's | |
48 | ;;; 2007 paper, "Compiling with Continuations, Continued". All Guile | |
49 | ;;; hackers should read that excellent paper! As in Kennedy's paper, | |
50 | ;;; continuations are second-class, and may be thought of as basic block | |
51 | ;;; labels. All values are bound to variables using continuation calls: | |
52 | ;;; even constants! | |
53 | ;;; | |
54 | ;;; There are some Guile-specific quirks as well: | |
55 | ;;; | |
36527695 | 56 | ;;; - $kreceive represents a continuation that receives multiple values, |
80b01fd0 AW |
57 | ;;; but which truncates them to some number of required values, |
58 | ;;; possibly with a rest list. | |
59 | ;;; | |
60 | ;;; - $kentry labels an entry point for a $fun (a function), and | |
61 | ;;; contains a $ktail representing the formal argument which is the | |
62 | ;;; function's continuation. | |
63 | ;;; | |
90dce16d AW |
64 | ;;; - $kentry also contain a $kclause continuation, corresponding to |
65 | ;;; the first case-lambda clause of the function. $kclause actually | |
66 | ;;; contains the clause body, and the subsequent clause (if any). | |
67 | ;;; This is because the $kclause logically matches or doesn't match | |
68 | ;;; a given set of actual arguments against a formal arity, then | |
69 | ;;; proceeds to a "body" continuation (which is a $kargs). | |
80b01fd0 AW |
70 | ;;; |
71 | ;;; That's to say that a $fun can be matched like this: | |
72 | ;;; | |
73 | ;;; (match f | |
6e422a35 AW |
74 | ;;; (($ $fun src meta free |
75 | ;;; ($ $cont kentry | |
80b01fd0 | 76 | ;;; ($ $kentry self ($ $cont ktail _ ($ $ktail)) |
90dce16d AW |
77 | ;;; ($ $kclause arity |
78 | ;;; ($ $cont kbody _ ($ $kargs names syms body)) | |
79 | ;;; alternate)))) | |
80b01fd0 AW |
80 | ;;; #t)) |
81 | ;;; | |
82 | ;;; A $continue to ktail is in tail position. $kentry, $kclause, | |
83 | ;;; and $ktail will never be seen elsewhere in a CPS term. | |
84 | ;;; | |
85 | ;;; - $prompt continues to the body of the prompt, having pushed on a | |
86 | ;;; prompt whose handler will continue at its "handler" | |
87 | ;;; continuation. The continuation of the prompt is responsible for | |
7ab76a83 | 88 | ;;; popping the prompt. |
80b01fd0 AW |
89 | ;;; |
90 | ;;; In summary: | |
91 | ;;; | |
92 | ;;; - $letk, $letrec, and $continue are terms. | |
93 | ;;; | |
94 | ;;; - $cont is a continuation, containing a continuation body ($kargs, | |
95 | ;;; $kif, etc). | |
96 | ;;; | |
97 | ;;; - $continue terms contain an expression ($call, $const, $fun, | |
98 | ;;; etc). | |
99 | ;;; | |
100 | ;;; See (language tree-il compile-cps) for details on how Tree-IL | |
101 | ;;; converts to CPS. | |
102 | ;;; | |
103 | ;;; Code: | |
104 | ||
105 | (define-module (language cps) | |
106 | #:use-module (ice-9 match) | |
107 | #:use-module ((srfi srfi-1) #:select (fold)) | |
108 | #:use-module (srfi srfi-9) | |
109 | #:use-module (srfi srfi-9 gnu) | |
828ed944 | 110 | #:use-module (srfi srfi-11) |
80b01fd0 AW |
111 | #:export (;; Helper. |
112 | $arity | |
113 | make-$arity | |
114 | ||
115 | ;; Terms. | |
116 | $letk $continue $letrec | |
117 | ||
118 | ;; Continuations. | |
119 | $cont | |
120 | ||
121 | ;; Continuation bodies. | |
36527695 | 122 | $kif $kreceive $kargs $kentry $ktail $kclause |
80b01fd0 AW |
123 | |
124 | ;; Expressions. | |
b3ae2b50 | 125 | $void $const $prim $fun $call $callk $primcall $values $prompt |
80b01fd0 | 126 | |
9a1dfb7d AW |
127 | ;; Fresh names. |
128 | label-counter var-counter | |
129 | fresh-label fresh-var | |
828ed944 AW |
130 | with-fresh-name-state compute-max-label-and-var |
131 | let-fresh | |
9a1dfb7d | 132 | |
80b01fd0 | 133 | ;; Building macros. |
80b01fd0 AW |
134 | build-cps-term build-cps-cont build-cps-exp |
135 | rewrite-cps-term rewrite-cps-cont rewrite-cps-exp | |
136 | ||
137 | ;; Misc. | |
138 | parse-cps unparse-cps | |
2c3c086e AW |
139 | make-cont-folder fold-conts fold-local-conts |
140 | visit-cont-successors)) | |
80b01fd0 AW |
141 | |
142 | ;; FIXME: Use SRFI-99, when Guile adds it. | |
143 | (define-syntax define-record-type* | |
144 | (lambda (x) | |
145 | (define (id-append ctx . syms) | |
146 | (datum->syntax ctx (apply symbol-append (map syntax->datum syms)))) | |
147 | (syntax-case x () | |
148 | ((_ name field ...) | |
149 | (and (identifier? #'name) (and-map identifier? #'(field ...))) | |
150 | (with-syntax ((cons (id-append #'name #'make- #'name)) | |
151 | (pred (id-append #'name #'name #'?)) | |
152 | ((getter ...) (map (lambda (f) | |
153 | (id-append f #'name #'- f)) | |
154 | #'(field ...)))) | |
155 | #'(define-record-type name | |
156 | (cons field ...) | |
157 | pred | |
158 | (field getter) | |
159 | ...)))))) | |
160 | ||
161 | (define-syntax-rule (define-cps-type name field ...) | |
162 | (begin | |
163 | (define-record-type* name field ...) | |
164 | (set-record-type-printer! name print-cps))) | |
165 | ||
166 | (define (print-cps exp port) | |
167 | (format port "#<cps ~S>" (unparse-cps exp))) | |
168 | ||
169 | ;; Helper. | |
170 | (define-record-type* $arity req opt rest kw allow-other-keys?) | |
171 | ||
172 | ;; Terms. | |
173 | (define-cps-type $letk conts body) | |
6e422a35 | 174 | (define-cps-type $continue k src exp) |
80b01fd0 AW |
175 | (define-cps-type $letrec names syms funs body) |
176 | ||
177 | ;; Continuations | |
6e422a35 | 178 | (define-cps-type $cont k cont) |
80b01fd0 | 179 | (define-cps-type $kif kt kf) |
36527695 | 180 | (define-cps-type $kreceive arity k) |
80b01fd0 | 181 | (define-cps-type $kargs names syms body) |
90dce16d | 182 | (define-cps-type $kentry self tail clause) |
80b01fd0 | 183 | (define-cps-type $ktail) |
90dce16d | 184 | (define-cps-type $kclause arity cont alternate) |
80b01fd0 AW |
185 | |
186 | ;; Expressions. | |
80b01fd0 AW |
187 | (define-cps-type $void) |
188 | (define-cps-type $const val) | |
189 | (define-cps-type $prim name) | |
6e422a35 | 190 | (define-cps-type $fun src meta free body) |
80b01fd0 | 191 | (define-cps-type $call proc args) |
b3ae2b50 | 192 | (define-cps-type $callk k proc args) |
80b01fd0 AW |
193 | (define-cps-type $primcall name args) |
194 | (define-cps-type $values args) | |
7ab76a83 | 195 | (define-cps-type $prompt escape? tag handler) |
80b01fd0 | 196 | |
9a1dfb7d AW |
197 | (define label-counter (make-parameter #f)) |
198 | (define var-counter (make-parameter #f)) | |
199 | ||
200 | (define (fresh-label) | |
828ed944 AW |
201 | (let ((count (or (label-counter) |
202 | (error "fresh-label outside with-fresh-name-state")))) | |
9a1dfb7d AW |
203 | (label-counter (1+ count)) |
204 | count)) | |
205 | ||
9a1dfb7d | 206 | (define (fresh-var) |
1eda52c8 | 207 | (let ((count (or (var-counter) |
828ed944 | 208 | (error "fresh-var outside with-fresh-name-state")))) |
1eda52c8 | 209 | (var-counter (1+ count)) |
9a1dfb7d AW |
210 | count)) |
211 | ||
212 | (define-syntax-rule (let-fresh (label ...) (var ...) body ...) | |
213 | (let ((label (fresh-label)) ... | |
214 | (var (fresh-var)) ...) | |
215 | body ...)) | |
216 | ||
828ed944 AW |
217 | (define-syntax-rule (with-fresh-name-state fun body ...) |
218 | (begin | |
219 | (when (or (label-counter) (var-counter)) | |
220 | (error "with-fresh-name-state should not be called recursively")) | |
221 | (call-with-values (lambda () | |
222 | (compute-max-label-and-var fun)) | |
223 | (lambda (max-label max-var) | |
1eda52c8 AW |
224 | (parameterize ((label-counter (1+ max-label)) |
225 | (var-counter (1+ max-var))) | |
828ed944 | 226 | body ...))))) |
80b01fd0 AW |
227 | |
228 | (define-syntax build-arity | |
229 | (syntax-rules (unquote) | |
230 | ((_ (unquote exp)) exp) | |
231 | ((_ (req opt rest kw allow-other-keys?)) | |
232 | (make-$arity req opt rest kw allow-other-keys?)))) | |
233 | ||
234 | (define-syntax build-cont-body | |
36527695 | 235 | (syntax-rules (unquote $kif $kreceive $kargs $kentry $ktail $kclause) |
80b01fd0 AW |
236 | ((_ (unquote exp)) |
237 | exp) | |
238 | ((_ ($kif kt kf)) | |
239 | (make-$kif kt kf)) | |
36527695 AW |
240 | ((_ ($kreceive req rest kargs)) |
241 | (make-$kreceive (make-$arity req '() rest '() #f) kargs)) | |
80b01fd0 AW |
242 | ((_ ($kargs (name ...) (sym ...) body)) |
243 | (make-$kargs (list name ...) (list sym ...) (build-cps-term body))) | |
244 | ((_ ($kargs names syms body)) | |
245 | (make-$kargs names syms (build-cps-term body))) | |
90dce16d AW |
246 | ((_ ($kentry self tail clause)) |
247 | (make-$kentry self (build-cps-cont tail) (build-cps-cont clause))) | |
80b01fd0 AW |
248 | ((_ ($ktail)) |
249 | (make-$ktail)) | |
90dce16d AW |
250 | ((_ ($kclause arity cont alternate)) |
251 | (make-$kclause (build-arity arity) (build-cps-cont cont) | |
252 | (build-cps-cont alternate))))) | |
80b01fd0 AW |
253 | |
254 | (define-syntax build-cps-cont | |
255 | (syntax-rules (unquote) | |
256 | ((_ (unquote exp)) exp) | |
6e422a35 | 257 | ((_ (k cont)) (make-$cont k (build-cont-body cont))))) |
80b01fd0 AW |
258 | |
259 | (define-syntax build-cps-exp | |
260 | (syntax-rules (unquote | |
b3ae2b50 | 261 | $void $const $prim $fun $call $callk $primcall $values $prompt) |
80b01fd0 | 262 | ((_ (unquote exp)) exp) |
80b01fd0 AW |
263 | ((_ ($void)) (make-$void)) |
264 | ((_ ($const val)) (make-$const val)) | |
265 | ((_ ($prim name)) (make-$prim name)) | |
6e422a35 AW |
266 | ((_ ($fun src meta free body)) |
267 | (make-$fun src meta free (build-cps-cont body))) | |
80b01fd0 AW |
268 | ((_ ($call proc (arg ...))) (make-$call proc (list arg ...))) |
269 | ((_ ($call proc args)) (make-$call proc args)) | |
b3ae2b50 AW |
270 | ((_ ($callk k proc (arg ...))) (make-$callk k proc (list arg ...))) |
271 | ((_ ($callk k proc args)) (make-$callk k proc args)) | |
80b01fd0 AW |
272 | ((_ ($primcall name (arg ...))) (make-$primcall name (list arg ...))) |
273 | ((_ ($primcall name args)) (make-$primcall name args)) | |
274 | ((_ ($values (arg ...))) (make-$values (list arg ...))) | |
275 | ((_ ($values args)) (make-$values args)) | |
7ab76a83 AW |
276 | ((_ ($prompt escape? tag handler)) |
277 | (make-$prompt escape? tag handler)))) | |
80b01fd0 AW |
278 | |
279 | (define-syntax build-cps-term | |
280 | (syntax-rules (unquote $letk $letk* $letconst $letrec $continue) | |
281 | ((_ (unquote exp)) | |
282 | exp) | |
283 | ((_ ($letk (unquote conts) body)) | |
284 | (make-$letk conts (build-cps-term body))) | |
285 | ((_ ($letk (cont ...) body)) | |
286 | (make-$letk (list (build-cps-cont cont) ...) | |
287 | (build-cps-term body))) | |
288 | ((_ ($letk* () body)) | |
289 | (build-cps-term body)) | |
290 | ((_ ($letk* (cont conts ...) body)) | |
291 | (build-cps-term ($letk (cont) ($letk* (conts ...) body)))) | |
292 | ((_ ($letconst () body)) | |
293 | (build-cps-term body)) | |
294 | ((_ ($letconst ((name sym val) tail ...) body)) | |
9a1dfb7d | 295 | (let-fresh (kconst) () |
80b01fd0 | 296 | (build-cps-term |
6e422a35 AW |
297 | ($letk ((kconst ($kargs (name) (sym) ($letconst (tail ...) body)))) |
298 | ($continue kconst (let ((props (source-properties val))) | |
299 | (and (pair? props) props)) | |
300 | ($const val)))))) | |
80b01fd0 AW |
301 | ((_ ($letrec names gensyms funs body)) |
302 | (make-$letrec names gensyms funs (build-cps-term body))) | |
6e422a35 AW |
303 | ((_ ($continue k src exp)) |
304 | (make-$continue k src (build-cps-exp exp))))) | |
80b01fd0 AW |
305 | |
306 | (define-syntax-rule (rewrite-cps-term x (pat body) ...) | |
307 | (match x | |
308 | (pat (build-cps-term body)) ...)) | |
309 | (define-syntax-rule (rewrite-cps-cont x (pat body) ...) | |
310 | (match x | |
311 | (pat (build-cps-cont body)) ...)) | |
312 | (define-syntax-rule (rewrite-cps-exp x (pat body) ...) | |
313 | (match x | |
314 | (pat (build-cps-exp body)) ...)) | |
315 | ||
316 | (define (parse-cps exp) | |
317 | (define (src exp) | |
318 | (let ((props (source-properties exp))) | |
319 | (and (pair? props) props))) | |
320 | (match exp | |
321 | ;; Continuations. | |
322 | (('letconst k (name sym c) body) | |
323 | (build-cps-term | |
6e422a35 AW |
324 | ($letk ((k ($kargs (name) (sym) |
325 | ,(parse-cps body)))) | |
326 | ($continue k (src exp) ($const c))))) | |
80b01fd0 AW |
327 | (('let k (name sym val) body) |
328 | (build-cps-term | |
6e422a35 AW |
329 | ($letk ((k ($kargs (name) (sym) |
330 | ,(parse-cps body)))) | |
80b01fd0 AW |
331 | ,(parse-cps val)))) |
332 | (('letk (cont ...) body) | |
333 | (build-cps-term | |
334 | ($letk ,(map parse-cps cont) ,(parse-cps body)))) | |
335 | (('k sym body) | |
336 | (build-cps-cont | |
6e422a35 | 337 | (sym ,(parse-cps body)))) |
80b01fd0 AW |
338 | (('kif kt kf) |
339 | (build-cont-body ($kif kt kf))) | |
36527695 AW |
340 | (('kreceive req rest k) |
341 | (build-cont-body ($kreceive req rest k))) | |
80b01fd0 AW |
342 | (('kargs names syms body) |
343 | (build-cont-body ($kargs names syms ,(parse-cps body)))) | |
90dce16d | 344 | (('kentry self tail clause) |
80b01fd0 | 345 | (build-cont-body |
90dce16d | 346 | ($kentry self ,(parse-cps tail) ,(and=> clause parse-cps)))) |
80b01fd0 AW |
347 | (('ktail) |
348 | (build-cont-body | |
349 | ($ktail))) | |
350 | (('kclause (req opt rest kw allow-other-keys?) body) | |
351 | (build-cont-body | |
352 | ($kclause (req opt rest kw allow-other-keys?) | |
90dce16d AW |
353 | ,(parse-cps body) |
354 | ,#f))) | |
355 | (('kclause (req opt rest kw allow-other-keys?) body alternate) | |
356 | (build-cont-body | |
357 | ($kclause (req opt rest kw allow-other-keys?) | |
358 | ,(parse-cps body) | |
359 | ,(parse-cps alternate)))) | |
80b01fd0 AW |
360 | (('kseq body) |
361 | (build-cont-body ($kargs () () ,(parse-cps body)))) | |
362 | ||
363 | ;; Calls. | |
364 | (('continue k exp) | |
6e422a35 | 365 | (build-cps-term ($continue k (src exp) ,(parse-cps exp)))) |
80b01fd0 AW |
366 | (('void) |
367 | (build-cps-exp ($void))) | |
368 | (('const exp) | |
369 | (build-cps-exp ($const exp))) | |
370 | (('prim name) | |
371 | (build-cps-exp ($prim name))) | |
372 | (('fun meta free body) | |
6e422a35 | 373 | (build-cps-exp ($fun (src exp) meta free ,(parse-cps body)))) |
80b01fd0 AW |
374 | (('letrec ((name sym fun) ...) body) |
375 | (build-cps-term | |
376 | ($letrec name sym (map parse-cps fun) ,(parse-cps body)))) | |
377 | (('call proc arg ...) | |
378 | (build-cps-exp ($call proc arg))) | |
b3ae2b50 AW |
379 | (('callk k proc arg ...) |
380 | (build-cps-exp ($callk k proc arg))) | |
80b01fd0 AW |
381 | (('primcall name arg ...) |
382 | (build-cps-exp ($primcall name arg))) | |
383 | (('values arg ...) | |
384 | (build-cps-exp ($values arg))) | |
7ab76a83 AW |
385 | (('prompt escape? tag handler) |
386 | (build-cps-exp ($prompt escape? tag handler))) | |
80b01fd0 AW |
387 | (_ |
388 | (error "unexpected cps" exp)))) | |
389 | ||
390 | (define (unparse-cps exp) | |
391 | (match exp | |
392 | ;; Continuations. | |
6e422a35 AW |
393 | (($ $letk (($ $cont k ($ $kargs (name) (sym) body))) |
394 | ($ $continue k src ($ $const c))) | |
80b01fd0 AW |
395 | `(letconst ,k (,name ,sym ,c) |
396 | ,(unparse-cps body))) | |
6e422a35 | 397 | (($ $letk (($ $cont k ($ $kargs (name) (sym) body))) val) |
80b01fd0 AW |
398 | `(let ,k (,name ,sym ,(unparse-cps val)) |
399 | ,(unparse-cps body))) | |
400 | (($ $letk conts body) | |
401 | `(letk ,(map unparse-cps conts) ,(unparse-cps body))) | |
6e422a35 | 402 | (($ $cont sym body) |
80b01fd0 AW |
403 | `(k ,sym ,(unparse-cps body))) |
404 | (($ $kif kt kf) | |
405 | `(kif ,kt ,kf)) | |
36527695 AW |
406 | (($ $kreceive ($ $arity req () rest '() #f) k) |
407 | `(kreceive ,req ,rest ,k)) | |
80b01fd0 AW |
408 | (($ $kargs () () body) |
409 | `(kseq ,(unparse-cps body))) | |
410 | (($ $kargs names syms body) | |
411 | `(kargs ,names ,syms ,(unparse-cps body))) | |
90dce16d AW |
412 | (($ $kentry self tail clause) |
413 | `(kentry ,self ,(unparse-cps tail) ,(unparse-cps clause))) | |
80b01fd0 AW |
414 | (($ $ktail) |
415 | `(ktail)) | |
90dce16d AW |
416 | (($ $kclause ($ $arity req opt rest kw allow-other-keys?) body alternate) |
417 | `(kclause (,req ,opt ,rest ,kw ,allow-other-keys?) ,(unparse-cps body) | |
418 | . ,(if alternate (list (unparse-cps alternate)) '()))) | |
80b01fd0 AW |
419 | |
420 | ;; Calls. | |
6e422a35 | 421 | (($ $continue k src exp) |
80b01fd0 | 422 | `(continue ,k ,(unparse-cps exp))) |
80b01fd0 AW |
423 | (($ $void) |
424 | `(void)) | |
425 | (($ $const val) | |
426 | `(const ,val)) | |
427 | (($ $prim name) | |
428 | `(prim ,name)) | |
6e422a35 | 429 | (($ $fun src meta free body) |
80b01fd0 AW |
430 | `(fun ,meta ,free ,(unparse-cps body))) |
431 | (($ $letrec names syms funs body) | |
432 | `(letrec ,(map (lambda (name sym fun) | |
433 | (list name sym (unparse-cps fun))) | |
434 | names syms funs) | |
435 | ,(unparse-cps body))) | |
436 | (($ $call proc args) | |
437 | `(call ,proc ,@args)) | |
b3ae2b50 AW |
438 | (($ $callk k proc args) |
439 | `(callk ,k ,proc ,@args)) | |
80b01fd0 AW |
440 | (($ $primcall name args) |
441 | `(primcall ,name ,@args)) | |
442 | (($ $values args) | |
443 | `(values ,@args)) | |
7ab76a83 AW |
444 | (($ $prompt escape? tag handler) |
445 | `(prompt ,escape? ,tag ,handler)) | |
80b01fd0 AW |
446 | (_ |
447 | (error "unexpected cps" exp)))) | |
448 | ||
a6f823bd | 449 | (define-syntax-rule (make-cont-folder global? seed ...) |
828ed944 AW |
450 | (lambda (proc fun seed ...) |
451 | (define (fold-values proc in seed ...) | |
452 | (if (null? in) | |
453 | (values seed ...) | |
454 | (let-values (((seed ...) (proc (car in) seed ...))) | |
455 | (fold-values proc (cdr in) seed ...)))) | |
456 | ||
457 | (define (cont-folder cont seed ...) | |
458 | (match cont | |
459 | (($ $cont k cont) | |
460 | (let-values (((seed ...) (proc k cont seed ...))) | |
461 | (match cont | |
462 | (($ $kargs names syms body) | |
463 | (term-folder body seed ...)) | |
464 | ||
90dce16d | 465 | (($ $kentry self tail clause) |
828ed944 | 466 | (let-values (((seed ...) (cont-folder tail seed ...))) |
90dce16d AW |
467 | (if clause |
468 | (cont-folder clause seed ...) | |
469 | (values seed ...)))) | |
470 | ||
471 | (($ $kclause arity body alternate) | |
472 | (let-values (((seed ...) (cont-folder body seed ...))) | |
473 | (if alternate | |
474 | (cont-folder alternate seed ...) | |
475 | (values seed ...)))) | |
828ed944 AW |
476 | |
477 | (_ (values seed ...))))))) | |
478 | ||
479 | (define (fun-folder fun seed ...) | |
480 | (match fun | |
481 | (($ $fun src meta free body) | |
482 | (cont-folder body seed ...)))) | |
483 | ||
484 | (define (term-folder term seed ...) | |
485 | (match term | |
486 | (($ $letk conts body) | |
487 | (let-values (((seed ...) (term-folder body seed ...))) | |
488 | (fold-values cont-folder conts seed ...))) | |
489 | ||
490 | (($ $continue k src exp) | |
491 | (match exp | |
a6f823bd AW |
492 | (($ $fun) |
493 | (if global? | |
494 | (fun-folder exp seed ...) | |
495 | (values seed ...))) | |
828ed944 AW |
496 | (_ (values seed ...)))) |
497 | ||
498 | (($ $letrec names syms funs body) | |
499 | (let-values (((seed ...) (term-folder body seed ...))) | |
a6f823bd AW |
500 | (if global? |
501 | (fold-values fun-folder funs seed ...) | |
502 | (values seed ...)))))) | |
828ed944 AW |
503 | |
504 | (fun-folder fun seed ...))) | |
505 | ||
506 | (define (compute-max-label-and-var fun) | |
a6f823bd | 507 | ((make-cont-folder #t max-label max-var) |
828ed944 AW |
508 | (lambda (label cont max-label max-var) |
509 | (values (max label max-label) | |
510 | (match cont | |
408da790 AW |
511 | (($ $kargs names vars body) |
512 | (let lp ((body body) (max-var (fold max max-var vars))) | |
513 | (match body | |
514 | (($ $letk conts body) (lp body max-var)) | |
515 | (($ $letrec names vars funs body) | |
516 | (lp body (fold max max-var vars))) | |
517 | (_ max-var)))) | |
828ed944 | 518 | (($ $kentry self) |
1eda52c8 | 519 | (max self max-var)) |
828ed944 AW |
520 | (_ max-var)))) |
521 | fun | |
522 | -1 | |
523 | -1)) | |
80b01fd0 | 524 | |
828ed944 | 525 | (define (fold-conts proc seed fun) |
a6f823bd | 526 | ((make-cont-folder #t seed) proc fun seed)) |
80b01fd0 | 527 | |
a6f823bd AW |
528 | (define (fold-local-conts proc seed fun) |
529 | ((make-cont-folder #f seed) proc fun seed)) | |
2c3c086e AW |
530 | |
531 | (define (visit-cont-successors proc cont) | |
532 | (match cont | |
533 | (($ $kargs names syms body) | |
534 | (let lp ((body body)) | |
535 | (match body | |
536 | (($ $letk conts body) (lp body)) | |
537 | (($ $letrec names vars funs body) (lp body)) | |
538 | (($ $continue k src exp) | |
539 | (match exp | |
540 | (($ $prompt escape? tag handler) (proc k handler)) | |
541 | (_ (proc k))))))) | |
542 | ||
543 | (($ $kif kt kf) (proc kt kf)) | |
544 | ||
545 | (($ $kreceive arity k) (proc k)) | |
546 | ||
547 | (($ $kclause arity ($ $cont kbody) #f) (proc kbody)) | |
548 | ||
549 | (($ $kclause arity ($ $cont kbody) ($ $cont kalt)) (proc kbody kalt)) | |
550 | ||
551 | (($ $kentry self tail ($ $cont clause)) (proc clause)) | |
552 | ||
553 | (($ $kentry self tail #f) (proc)) | |
554 | ||
555 | (($ $ktail) (proc)))) |