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51248e6e DK |
1 | ;;; Guile Emac Lisp |
2 | ||
3 | ;; Copyright (C) 2001 Free Software Foundation, Inc. | |
4 | ||
5 | ;; This program is free software; you can redistribute it and/or modify | |
6 | ;; it under the terms of the GNU General Public License as published by | |
7 | ;; the Free Software Foundation; either version 2, or (at your option) | |
8 | ;; any later version. | |
9 | ;; | |
10 | ;; This program 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 | |
13 | ;; GNU General Public License for more details. | |
14 | ;; | |
15 | ;; You should have received a copy of the GNU General Public License | |
16 | ;; along with this program; see the file COPYING. If not, write to | |
17 | ;; the Free Software Foundation, Inc., 59 Temple Place - Suite 330, | |
18 | ;; Boston, MA 02111-1307, USA. | |
19 | ||
20 | ;;; Code: | |
21 | ||
22 | (define-module (language elisp compile-tree-il) | |
23 | #:use-module (language tree-il) | |
24 | #:use-module (system base pmatch) | |
25 | #:export (compile-tree-il)) | |
26 | ||
27 | ||
28 | ; Find the source properties of some parsed expression if there are any | |
29 | ; associated with it. | |
30 | ||
31 | (define (location x) | |
32 | (and (pair? x) | |
33 | (let ((props (source-properties x))) | |
34 | (and (not (null? props)) | |
35 | props)))) | |
36 | ||
37 | ||
fdfb36de | 38 | ; Value to use for Elisp's nil and t. |
4530432e | 39 | |
a4316739 | 40 | (define (nil-value loc) (make-const loc #f)) |
fdfb36de | 41 | (define (t-value loc) (make-const loc #t)) |
4530432e DK |
42 | |
43 | ||
344927c3 DK |
44 | ; Modules that contain the value and function slot bindings. |
45 | ||
46 | (define runtime '(language elisp runtime)) | |
47 | (define value-slot '(language elisp runtime value-slot)) | |
48 | (define function-slot '(language elisp runtime function-slot)) | |
49 | ||
50 | ||
50abfe76 DK |
51 | ; Build a call to a primitive procedure nicely. |
52 | ||
53 | (define (call-primitive loc sym . args) | |
54 | (make-application loc (make-primitive-ref loc sym) args)) | |
55 | ||
56 | ||
57 | ; Error reporting routine for syntax/compilation problems or build code for | |
58 | ; a runtime-error output. | |
344927c3 DK |
59 | |
60 | (define (report-error loc . args) | |
61 | (apply error args)) | |
62 | ||
50abfe76 DK |
63 | (define (runtime-error loc msg . args) |
64 | (make-application loc (make-primitive-ref loc 'error) | |
65 | (cons (make-const loc msg) args))) | |
66 | ||
344927c3 DK |
67 | |
68 | ; Generate code to ensure a fluid is there for further use of a given symbol. | |
69 | ||
70 | (define (ensure-fluid! loc sym module) | |
71 | ; FIXME: Do this! | |
72 | (make-void loc)) | |
73 | ||
74 | ||
75 | ; Generate code to reference a fluid saved variable. | |
76 | ||
77 | (define (reference-variable loc sym module) | |
78 | (make-sequence loc | |
79 | (list (ensure-fluid! loc sym module) | |
50abfe76 DK |
80 | (call-primitive loc 'fluid-ref |
81 | (make-module-ref loc module sym #t))))) | |
344927c3 DK |
82 | |
83 | ||
84 | ; Reference a variable and error if the value is void. | |
85 | ||
86 | (define (reference-with-check loc sym module) | |
87 | (let ((var (gensym))) | |
88 | (make-let loc '(value) `(,var) `(,(reference-variable loc sym module)) | |
89 | (make-conditional loc | |
50abfe76 DK |
90 | (call-primitive loc 'eq? |
91 | (make-module-ref loc runtime 'void #t) | |
92 | (make-lexical-ref loc 'value var)) | |
93 | (runtime-error loc "variable is void:" (make-const loc sym)) | |
344927c3 DK |
94 | (make-lexical-ref loc 'value var))))) |
95 | ||
96 | ||
97 | ; Generate code to set a fluid saved variable. | |
98 | ||
99 | (define (set-variable! loc sym module value) | |
100 | (make-sequence loc | |
101 | (list (ensure-fluid! loc sym module) | |
50abfe76 DK |
102 | (call-primitive loc 'fluid-set! |
103 | (make-module-ref loc module sym #t) | |
104 | value)))) | |
344927c3 DK |
105 | |
106 | ||
3a4b8635 DK |
107 | ; Process the bindings part of a let or let* expression; that is, check for |
108 | ; correctness and bring it to the form ((sym1 . val1) (sym2 . val2) ...). | |
109 | ||
110 | (define (process-let-bindings loc bindings) | |
111 | (map (lambda (b) | |
112 | (if (symbol? b) | |
113 | (cons b 'nil) | |
114 | (if (or (not (list? b)) | |
115 | (not (= (length b) 2))) | |
116 | (report-error loc "expected symbol or list of 2 elements in let") | |
117 | (if (not (symbol? (car b))) | |
118 | (report-error loc "expected symbol in let") | |
119 | (cons (car b) (cadr b)))))) | |
120 | bindings)) | |
121 | ||
122 | ||
50abfe76 DK |
123 | ; Split the argument list of a lambda expression into required, optional and |
124 | ; rest arguments and also check it is actually valid. | |
125 | ||
126 | (define (split-lambda-arguments loc args) | |
127 | (let iterate ((tail args) | |
128 | (mode 'required) | |
129 | (required '()) | |
130 | (optional '())) | |
131 | (cond | |
132 | ||
133 | ((null? tail) | |
134 | (values (reverse required) (reverse optional) #f)) | |
135 | ||
136 | ((and (eq? mode 'required) | |
137 | (eq? (car tail) '&optional)) | |
138 | (iterate (cdr tail) 'optional required optional)) | |
139 | ||
140 | ((eq? (car tail) '&rest) | |
141 | (if (or (null? (cdr tail)) | |
142 | (not (null? (cddr tail)))) | |
143 | (report-error loc "expected exactly one symbol after &rest") | |
144 | (values (reverse required) (reverse optional) (cadr tail)))) | |
145 | ||
146 | (else | |
147 | (if (not (symbol? (car tail))) | |
148 | (report-error loc "expected symbol in argument list, got" (car tail)) | |
149 | (case mode | |
150 | ((required) (iterate (cdr tail) mode | |
151 | (cons (car tail) required) optional)) | |
152 | ((optional) (iterate (cdr tail) mode | |
153 | required (cons (car tail) optional))) | |
154 | ((else) (error "invalid mode in split-lambda-arguments" mode)))))))) | |
155 | ||
156 | ||
157 | ; Compile a lambda expression. Things get a little complicated because TreeIL | |
158 | ; does not allow optional arguments but only one rest argument, and also the | |
159 | ; rest argument should be nil instead of '() for no values given. Because of | |
160 | ; this, we have to do a little preprocessing to get everything done before the | |
161 | ; real body is called. | |
162 | ; | |
163 | ; (lambda (a &optional b &rest c) body) should become: | |
164 | ; (lambda (a_ . rest_) | |
165 | ; (with-fluids* (list a b c) (list a_ nil nil) | |
166 | ; (lambda () | |
167 | ; (if (not (null? rest_)) | |
168 | ; (begin | |
169 | ; (fluid-set! b (car rest_)) | |
170 | ; (set! rest_ (cdr rest_)) | |
171 | ; (if (not (null? rest_)) | |
172 | ; (fluid-set! c rest_)))) | |
173 | ; body))) | |
174 | ; | |
175 | ; This is formulated quite imperatively, but I think in this case that is quite | |
176 | ; clear and better than creating a lot of nested let's. | |
177 | ||
178 | (define (compile-lambda loc args body) | |
179 | (call-with-values | |
180 | (lambda () | |
181 | (split-lambda-arguments loc args)) | |
182 | (lambda (required optional rest) | |
183 | ; FIXME: Ensure fluids there! | |
184 | (let ((required-sym (map (lambda (sym) (gensym)) required)) | |
185 | (rest-sym (if (or rest (not (null? optional))) (gensym) '()))) | |
186 | (let ((real-args (append required-sym rest-sym))) | |
187 | (make-lambda loc | |
188 | real-args real-args '() | |
189 | (call-primitive loc 'with-fluids* | |
190 | (make-application loc (make-primitive-ref loc 'list) | |
191 | (map (lambda (sym) (make-module-ref loc value-slot sym #t)) | |
192 | (append (append required optional) | |
193 | (if rest (list rest) '())))) | |
194 | (make-application loc (make-primitive-ref loc 'list) | |
195 | (append (map (lambda (sym) (make-lexical-ref loc sym sym)) | |
196 | required-sym) | |
197 | (map (lambda (sym) (nil-value loc)) | |
198 | (if (null? rest-sym) | |
199 | optional | |
200 | (append optional (list rest-sym)))))) | |
201 | (make-lambda loc '() '() '() | |
202 | (make-sequence loc | |
203 | (cons (process-optionals loc optional rest-sym) | |
204 | (cons (process-rest loc rest rest-sym) | |
205 | (map compile-expr body)))))))))))) | |
206 | ||
207 | ; Build the code to handle setting of optional arguments that are present | |
208 | ; and updating the rest list. | |
209 | (define (process-optionals loc optional rest-sym) | |
210 | (let iterate ((tail optional)) | |
211 | (if (null? tail) | |
212 | (make-void loc) | |
213 | (make-conditional loc | |
214 | (call-primitive loc 'null? (make-lexical-ref loc rest-sym rest-sym)) | |
215 | (make-void loc) | |
216 | (make-sequence loc | |
217 | (list (set-variable! loc (car tail) value-slot | |
218 | (call-primitive loc 'car | |
219 | (make-lexical-ref loc rest-sym rest-sym))) | |
220 | (make-lexical-set loc rest-sym rest-sym | |
221 | (call-primitive loc 'cdr | |
222 | (make-lexical-ref loc rest-sym rest-sym))) | |
223 | (iterate (cdr tail)))))))) | |
224 | ||
225 | ; This builds the code to set the rest variable to nil if it is empty. | |
226 | (define (process-rest loc rest rest-sym) | |
227 | (let ((rest-empty (call-primitive loc 'null? | |
228 | (make-lexical-ref loc rest-sym rest-sym)))) | |
229 | (cond | |
230 | (rest | |
231 | (make-conditional loc rest-empty | |
232 | (make-void loc) | |
233 | (set-variable! loc rest value-slot | |
234 | (make-lexical-ref loc rest-sym rest-sym)))) | |
235 | ((not (null? rest-sym)) | |
236 | (make-conditional loc rest-empty | |
237 | (make-void loc) | |
238 | (runtime-error loc "too many arguments and no rest argument"))) | |
239 | (else (make-void loc))))) | |
240 | ||
241 | ||
51248e6e DK |
242 | ; Compile a symbol expression. This is a variable reference or maybe some |
243 | ; special value like nil. | |
244 | ||
245 | (define (compile-symbol loc sym) | |
246 | (case sym | |
247 | ||
fdfb36de | 248 | ((nil) (nil-value loc)) |
51248e6e | 249 | |
fdfb36de | 250 | ((t) (t-value loc)) |
51248e6e | 251 | |
51248e6e | 252 | (else |
344927c3 | 253 | (reference-with-check loc sym value-slot)))) |
51248e6e DK |
254 | |
255 | ||
256 | ; Compile a pair-expression (that is, any structure-like construct). | |
257 | ||
258 | (define (compile-pair loc expr) | |
259 | (pmatch expr | |
260 | ||
261 | ((progn . ,forms) | |
262 | (make-sequence loc (map compile-expr forms))) | |
263 | ||
264 | ((if ,condition ,ifclause) | |
265 | (make-conditional loc (compile-expr condition) | |
266 | (compile-expr ifclause) | |
4530432e | 267 | (nil-value loc))) |
51248e6e DK |
268 | ((if ,condition ,ifclause ,elseclause) |
269 | (make-conditional loc (compile-expr condition) | |
270 | (compile-expr ifclause) | |
271 | (compile-expr elseclause))) | |
272 | ((if ,condition ,ifclause . ,elses) | |
273 | (make-conditional loc (compile-expr condition) | |
274 | (compile-expr ifclause) | |
275 | (make-sequence loc (map compile-expr elses)))) | |
276 | ||
a4316739 DK |
277 | ; For (cond ...) forms, a special case is a (condition) clause without |
278 | ; body. In this case, the value of condition itself should be returned, | |
279 | ; and thus is saved in a local variable for testing and returning, if it | |
280 | ; is found true. | |
51248e6e DK |
281 | ((cond . ,clauses) (guard (and-map (lambda (el) |
282 | (and (list? el) (not (null? el)))) | |
283 | clauses)) | |
284 | (let iterate ((tail clauses)) | |
285 | (if (null? tail) | |
4530432e | 286 | (nil-value loc) |
51248e6e | 287 | (let ((cur (car tail))) |
a4316739 DK |
288 | (if (null? (cdr cur)) |
289 | (let ((var (gensym))) | |
290 | (make-let loc | |
291 | '(condition) `(,var) `(,(compile-expr (car cur))) | |
292 | (make-conditional loc | |
293 | (make-lexical-ref loc 'condition var) | |
294 | (make-lexical-ref loc 'condition var) | |
295 | (iterate (cdr tail))))) | |
296 | (make-conditional loc | |
297 | (compile-expr (car cur)) | |
298 | (make-sequence loc (map compile-expr (cdr cur))) | |
299 | (iterate (cdr tail)))))))) | |
51248e6e | 300 | |
fdfb36de | 301 | ((and) (t-value loc)) |
51248e6e DK |
302 | ((and . ,expressions) |
303 | (let iterate ((tail expressions)) | |
304 | (if (null? (cdr tail)) | |
305 | (compile-expr (car tail)) | |
306 | (make-conditional loc | |
307 | (compile-expr (car tail)) | |
308 | (iterate (cdr tail)) | |
4530432e | 309 | (nil-value loc))))) |
51248e6e | 310 | |
fdfb36de DK |
311 | ((or . ,expressions) |
312 | (let iterate ((tail expressions)) | |
313 | (if (null? tail) | |
314 | (nil-value loc) | |
315 | (let ((var (gensym))) | |
316 | (make-let loc | |
317 | '(condition) `(,var) `(,(compile-expr (car tail))) | |
318 | (make-conditional loc | |
319 | (make-lexical-ref loc 'condition var) | |
320 | (make-lexical-ref loc 'condition var) | |
321 | (iterate (cdr tail)))))))) | |
322 | ||
344927c3 DK |
323 | ; Build a set form for possibly multiple values. The code is not formulated |
324 | ; tail recursive because it is clearer this way and large lists of symbol | |
325 | ; expression pairs are very unlikely. | |
326 | ((setq . ,args) | |
327 | (make-sequence loc | |
328 | (let iterate ((tail args)) | |
329 | (if (null? tail) | |
330 | (list (make-void loc)) | |
331 | (let ((sym (car tail)) | |
332 | (tailtail (cdr tail))) | |
333 | (if (not (symbol? sym)) | |
334 | (report-error loc "expected symbol in setq") | |
335 | (if (null? tailtail) | |
336 | (report-error loc "missing value for symbol in setq" sym) | |
337 | (let* ((val (compile-expr (car tailtail))) | |
338 | (op (set-variable! loc sym value-slot val))) | |
339 | (cons op (iterate (cdr tailtail))))))))))) | |
340 | ||
3a4b8635 DK |
341 | ; Let is done with a single call to with-fluids* binding them locally to new |
342 | ; values. | |
343 | ((let ,bindings . ,body) (guard (and (list? bindings) | |
344 | (list? body) | |
345 | (not (null? bindings)) | |
346 | (not (null? body)))) | |
347 | (let ((bind (process-let-bindings loc bindings))) | |
50abfe76 DK |
348 | (call-primitive loc 'with-fluids* |
349 | (make-application loc (make-primitive-ref loc 'list) | |
350 | (map (lambda (el) | |
351 | (make-module-ref loc value-slot (car el) #t)) | |
352 | bind)) | |
353 | (make-application loc (make-primitive-ref loc 'list) | |
354 | (map (lambda (el) | |
355 | (compile-expr (cdr el))) | |
356 | bind)) | |
357 | (make-lambda loc '() '() '() | |
358 | (make-sequence loc (map compile-expr body)))))) | |
3a4b8635 DK |
359 | |
360 | ; Let* is compiled to a cascaded set of with-fluid* for each binding in turn | |
361 | ; so that each one already sees the preceding bindings. | |
362 | ((let* ,bindings . ,body) (guard (and (list? bindings) | |
363 | (list? body) | |
364 | (not (null? bindings)) | |
365 | (not (null? body)))) | |
366 | (let ((bind (process-let-bindings loc bindings))) | |
367 | (let iterate ((tail bind)) | |
368 | (if (null? tail) | |
369 | (make-sequence loc (map compile-expr body)) | |
50abfe76 DK |
370 | (call-primitive loc 'with-fluid* |
371 | (make-module-ref loc value-slot (caar tail) #t) | |
372 | (compile-expr (cdar tail)) | |
373 | (make-lambda loc '() '() '() (iterate (cdr tail)))))))) | |
3a4b8635 | 374 | |
d221c18b DK |
375 | ; A while construct is transformed into a tail-recursive loop like this: |
376 | ; (letrec ((iterate (lambda () | |
377 | ; (if condition | |
378 | ; (begin body | |
379 | ; (iterate)) | |
380 | ; %nil)))) | |
381 | ; (iterate)) | |
382 | ((while ,condition . ,body) | |
383 | (let* ((itersym (gensym)) | |
384 | (compiled-body (map compile-expr body)) | |
385 | (iter-call (make-application loc | |
386 | (make-lexical-ref loc 'iterate itersym) | |
387 | (list))) | |
388 | (full-body (make-sequence loc | |
389 | (append compiled-body (list iter-call)))) | |
390 | (lambda-body (make-conditional loc | |
391 | (compile-expr condition) | |
392 | full-body | |
393 | (nil-value loc))) | |
394 | (iter-thunk (make-lambda loc '() '() '() lambda-body))) | |
395 | (make-letrec loc '(iterate) (list itersym) (list iter-thunk) | |
396 | iter-call))) | |
397 | ||
50abfe76 DK |
398 | ; Either (lambda ...) or (function (lambda ...)) denotes a lambda-expression |
399 | ; that should be compiled. | |
400 | ((lambda ,args . ,body) (guard (not (null? body))) | |
401 | (compile-lambda loc args body)) | |
402 | ((function (lambda ,args . ,body)) (guard (not (null? body))) | |
403 | (compile-lambda loc args body)) | |
404 | ||
51248e6e DK |
405 | (('quote ,val) |
406 | (make-const loc val)) | |
407 | ||
408 | (else | |
344927c3 | 409 | (report-error loc "unrecognized elisp" expr)))) |
51248e6e DK |
410 | |
411 | ||
412 | ; Compile a single expression to TreeIL. | |
413 | ||
414 | (define (compile-expr expr) | |
415 | (let ((loc (location expr))) | |
416 | (cond | |
417 | ((symbol? expr) | |
418 | (compile-symbol loc expr)) | |
419 | ((pair? expr) | |
420 | (compile-pair loc expr)) | |
421 | (else (make-const loc expr))))) | |
422 | ||
423 | ||
424 | ; Entry point for compilation to TreeIL. | |
425 | ||
426 | (define (compile-tree-il expr env opts) | |
427 | (values | |
428 | (compile-expr expr) | |
429 | env | |
430 | env)) |