Commit | Line | Data |
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4845bbae | 1 | /* Copyright (C) 1995,1996,1998,1999,2000,2001, 2003, 2004 Free Software Foundation, Inc. |
0f2d19dd | 2 | * |
73be1d9e MV |
3 | * This library is free software; you can redistribute it and/or |
4 | * modify it under the terms of the GNU Lesser General Public | |
5 | * License as published by the Free Software Foundation; either | |
6 | * version 2.1 of the License, or (at your option) any later version. | |
0f2d19dd | 7 | * |
73be1d9e MV |
8 | * This library is distributed in the hope that it will be useful, |
9 | * but WITHOUT ANY WARRANTY; without even the implied warranty of | |
10 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU | |
11 | * Lesser General Public License for more details. | |
0f2d19dd | 12 | * |
73be1d9e MV |
13 | * You should have received a copy of the GNU Lesser General Public |
14 | * License along with this library; if not, write to the Free Software | |
15 | * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA | |
16 | */ | |
1bbd0b84 | 17 | |
1bbd0b84 | 18 | |
0f2d19dd JB |
19 | \f |
20 | ||
4845bbae MV |
21 | #include <assert.h> |
22 | ||
a0599745 MD |
23 | #include "libguile/_scm.h" |
24 | #include "libguile/eval.h" | |
25 | #include "libguile/alist.h" | |
26 | #include "libguile/fluids.h" | |
27 | #include "libguile/ports.h" | |
28 | #include "libguile/smob.h" | |
0f2d19dd | 29 | |
a0599745 | 30 | #include "libguile/dynwind.h" |
0f2d19dd JB |
31 | \f |
32 | ||
33 | /* {Dynamic wind} | |
b3460a50 MV |
34 | |
35 | Things that can be on the wind list: | |
36 | ||
4845bbae MV |
37 | #<frame> |
38 | #<winder> | |
b3460a50 MV |
39 | (enter-proc . leave-proc) dynamic-wind |
40 | (tag . jmpbuf) catch | |
41 | (tag . lazy-catch) lazy-catch | |
42 | tag is either a symbol or a boolean | |
43 | ||
b3460a50 | 44 | */ |
0f2d19dd JB |
45 | |
46 | ||
47 | ||
3b3b36dd | 48 | SCM_DEFINE (scm_dynamic_wind, "dynamic-wind", 3, 0, 0, |
1e6808ea MG |
49 | (SCM in_guard, SCM thunk, SCM out_guard), |
50 | "All three arguments must be 0-argument procedures.\n" | |
51 | "@var{in_guard} is called, then @var{thunk}, then\n" | |
52 | "@var{out_guard}.\n" | |
53 | "\n" | |
54 | "If, any time during the execution of @var{thunk}, the\n" | |
55 | "continuation of the @code{dynamic_wind} expression is escaped\n" | |
56 | "non-locally, @var{out_guard} is called. If the continuation of\n" | |
57 | "the dynamic-wind is re-entered, @var{in_guard} is called. Thus\n" | |
58 | "@var{in_guard} and @var{out_guard} may be called any number of\n" | |
59 | "times.\n" | |
60 | "@lisp\n" | |
b380b885 | 61 | "(define x 'normal-binding)\n" |
1e6808ea | 62 | "@result{} x\n" |
9401323e | 63 | "(define a-cont (call-with-current-continuation\n" |
b380b885 MD |
64 | " (lambda (escape)\n" |
65 | " (let ((old-x x))\n" | |
66 | " (dynamic-wind\n" | |
67 | " ;; in-guard:\n" | |
68 | " ;;\n" | |
1e6808ea MG |
69 | " (lambda () (set! x 'special-binding))\n" |
70 | "\n" | |
b380b885 MD |
71 | " ;; thunk\n" |
72 | " ;;\n" | |
73 | " (lambda () (display x) (newline)\n" | |
74 | " (call-with-current-continuation escape)\n" | |
75 | " (display x) (newline)\n" | |
1e6808ea MG |
76 | " x)\n" |
77 | "\n" | |
b380b885 MD |
78 | " ;; out-guard:\n" |
79 | " ;;\n" | |
1e6808ea MG |
80 | " (lambda () (set! x old-x)))))))\n" |
81 | "\n" | |
9401323e | 82 | ";; Prints:\n" |
b380b885 MD |
83 | "special-binding\n" |
84 | ";; Evaluates to:\n" | |
1e6808ea | 85 | "@result{} a-cont\n" |
b380b885 | 86 | "x\n" |
1e6808ea | 87 | "@result{} normal-binding\n" |
b380b885 MD |
88 | "(a-cont #f)\n" |
89 | ";; Prints:\n" | |
90 | "special-binding\n" | |
91 | ";; Evaluates to:\n" | |
1e6808ea | 92 | "@result{} a-cont ;; the value of the (define a-cont...)\n" |
b380b885 | 93 | "x\n" |
1e6808ea | 94 | "@result{} normal-binding\n" |
b380b885 MD |
95 | "a-cont\n" |
96 | "@result{} special-binding\n" | |
1e6808ea | 97 | "@end lisp") |
1bbd0b84 | 98 | #define FUNC_NAME s_scm_dynamic_wind |
0f2d19dd JB |
99 | { |
100 | SCM ans; | |
7888309b | 101 | SCM_ASSERT (scm_is_true (scm_thunk_p (out_guard)), |
1e6808ea | 102 | out_guard, |
1bbd0b84 | 103 | SCM_ARG3, FUNC_NAME); |
fdc28395 | 104 | scm_call_0 (in_guard); |
1e6808ea | 105 | scm_dynwinds = scm_acons (in_guard, out_guard, scm_dynwinds); |
fdc28395 | 106 | ans = scm_call_0 (thunk); |
0f2d19dd | 107 | scm_dynwinds = SCM_CDR (scm_dynwinds); |
fdc28395 | 108 | scm_call_0 (out_guard); |
0f2d19dd JB |
109 | return ans; |
110 | } | |
1bbd0b84 | 111 | #undef FUNC_NAME |
0f2d19dd | 112 | |
3346a90f | 113 | SCM |
92c2555f MV |
114 | scm_internal_dynamic_wind (scm_t_guard before, |
115 | scm_t_inner inner, | |
116 | scm_t_guard after, | |
3346a90f MD |
117 | void *inner_data, |
118 | void *guard_data) | |
119 | { | |
4845bbae MV |
120 | SCM ans; |
121 | ||
0888de4f | 122 | scm_frame_begin (SCM_F_FRAME_REWINDABLE); |
16c5cac2 MV |
123 | scm_frame_rewind_handler (before, guard_data, SCM_F_WIND_EXPLICITLY); |
124 | scm_frame_unwind_handler (after, guard_data, SCM_F_WIND_EXPLICITLY); | |
3346a90f | 125 | ans = inner (inner_data); |
0888de4f | 126 | scm_frame_end (); |
3346a90f MD |
127 | return ans; |
128 | } | |
1cc91f1b | 129 | |
4845bbae MV |
130 | /* Frames and winders. */ |
131 | ||
132 | static scm_t_bits tc16_frame; | |
133 | #define FRAME_P(f) SCM_SMOB_PREDICATE (tc16_frame, (f)) | |
134 | ||
f5710d53 MV |
135 | #define FRAME_F_REWINDABLE (1 << 0) |
136 | #define FRAME_REWINDABLE_P(f) (SCM_SMOB_FLAGS(f) & FRAME_F_REWINDABLE) | |
4845bbae MV |
137 | |
138 | static scm_t_bits tc16_winder; | |
14578fa4 | 139 | #define WINDER_P(w) SCM_SMOB_PREDICATE (tc16_winder, (w)) |
f5710d53 MV |
140 | #define WINDER_PROC(w) ((void (*)(void *))SCM_SMOB_DATA (w)) |
141 | #define WINDER_DATA(w) ((void *)SCM_SMOB_DATA_2 (w)) | |
4845bbae | 142 | |
f5710d53 MV |
143 | #define WINDER_F_EXPLICIT (1 << 0) |
144 | #define WINDER_F_REWIND (1 << 1) | |
145 | #define WINDER_F_MARK (1 << 2) | |
146 | #define WINDER_EXPLICIT_P(w) (SCM_SMOB_FLAGS(w) & WINDER_F_EXPLICIT) | |
147 | #define WINDER_REWIND_P(w) (SCM_SMOB_FLAGS(w) & WINDER_F_REWIND) | |
148 | #define WINDER_MARK_P(w) (SCM_SMOB_FLAGS(w) & WINDER_F_MARK) | |
4845bbae MV |
149 | |
150 | void | |
0888de4f | 151 | scm_frame_begin (scm_t_frame_flags flags) |
4845bbae MV |
152 | { |
153 | SCM f; | |
f5710d53 MV |
154 | SCM_NEWSMOB (f, tc16_frame, 0); |
155 | if (flags & SCM_F_FRAME_REWINDABLE) | |
156 | SCM_SET_SMOB_FLAGS (f, FRAME_F_REWINDABLE); | |
4845bbae MV |
157 | scm_dynwinds = scm_cons (f, scm_dynwinds); |
158 | } | |
159 | ||
160 | void | |
0888de4f | 161 | scm_frame_end (void) |
4845bbae | 162 | { |
0888de4f MV |
163 | /* Unwind upto and including the next frame entry. We can only |
164 | encounter #<winder> entries on the way. | |
4845bbae MV |
165 | */ |
166 | ||
0888de4f | 167 | while (SCM_CONSP (scm_dynwinds)) |
4845bbae | 168 | { |
0888de4f MV |
169 | SCM entry = SCM_CAR (scm_dynwinds); |
170 | scm_dynwinds = SCM_CDR (scm_dynwinds); | |
171 | ||
172 | if (FRAME_P (entry)) | |
173 | return; | |
174 | ||
175 | assert (WINDER_P (entry)); | |
176 | if (!WINDER_REWIND_P (entry) && WINDER_EXPLICIT_P (entry)) | |
177 | WINDER_PROC(entry) (WINDER_DATA (entry)); | |
4845bbae MV |
178 | } |
179 | ||
180 | assert (0); | |
181 | } | |
182 | ||
a520e4f0 MV |
183 | static SCM |
184 | winder_mark (SCM w) | |
185 | { | |
186 | if (WINDER_MARK_P (w)) | |
78addfa3 | 187 | return SCM_PACK (WINDER_DATA (w)); |
a520e4f0 MV |
188 | return SCM_BOOL_F; |
189 | } | |
190 | ||
4845bbae | 191 | void |
16c5cac2 MV |
192 | scm_frame_unwind_handler (void (*proc) (void *), void *data, |
193 | scm_t_wind_flags flags) | |
4845bbae MV |
194 | { |
195 | SCM w; | |
f5710d53 MV |
196 | SCM_NEWSMOB2 (w, tc16_winder, (scm_t_bits) proc, (scm_t_bits) data); |
197 | if (flags & SCM_F_WIND_EXPLICITLY) | |
198 | SCM_SET_SMOB_FLAGS (w, WINDER_F_EXPLICIT); | |
4845bbae MV |
199 | scm_dynwinds = scm_cons (w, scm_dynwinds); |
200 | } | |
201 | ||
202 | void | |
16c5cac2 MV |
203 | scm_frame_rewind_handler (void (*proc) (void *), void *data, |
204 | scm_t_wind_flags flags) | |
4845bbae MV |
205 | { |
206 | SCM w; | |
f5710d53 MV |
207 | SCM_NEWSMOB2 (w, tc16_winder, (scm_t_bits) proc, (scm_t_bits) data); |
208 | SCM_SET_SMOB_FLAGS (w, WINDER_F_REWIND); | |
4845bbae | 209 | scm_dynwinds = scm_cons (w, scm_dynwinds); |
a520e4f0 MV |
210 | if (flags & SCM_F_WIND_EXPLICITLY) |
211 | proc (data); | |
212 | } | |
213 | ||
214 | void | |
16c5cac2 MV |
215 | scm_frame_unwind_handler_with_scm (void (*proc) (SCM), SCM data, |
216 | scm_t_wind_flags flags) | |
a520e4f0 MV |
217 | { |
218 | SCM w; | |
219 | scm_t_bits fl = ((flags&SCM_F_WIND_EXPLICITLY)? WINDER_F_EXPLICIT : 0); | |
f5710d53 MV |
220 | SCM_NEWSMOB2 (w, tc16_winder, (scm_t_bits) proc, SCM_UNPACK (data)); |
221 | SCM_SET_SMOB_FLAGS (w, fl | WINDER_F_MARK); | |
a520e4f0 MV |
222 | scm_dynwinds = scm_cons (w, scm_dynwinds); |
223 | } | |
224 | ||
225 | void | |
16c5cac2 MV |
226 | scm_frame_rewind_handler_with_scm (void (*proc) (SCM), SCM data, |
227 | scm_t_wind_flags flags) | |
a520e4f0 MV |
228 | { |
229 | SCM w; | |
f5710d53 MV |
230 | SCM_NEWSMOB2 (w, tc16_winder, (scm_t_bits) proc, SCM_UNPACK (data)); |
231 | SCM_SET_SMOB_FLAGS (w, WINDER_F_REWIND | WINDER_F_MARK); | |
a520e4f0 MV |
232 | scm_dynwinds = scm_cons (w, scm_dynwinds); |
233 | if (flags & SCM_F_WIND_EXPLICITLY) | |
4845bbae MV |
234 | proc (data); |
235 | } | |
236 | ||
6d5649b7 MV |
237 | void |
238 | scm_frame_free (void *mem) | |
239 | { | |
240 | scm_frame_unwind_handler (free, mem, SCM_F_WIND_EXPLICITLY); | |
241 | } | |
242 | ||
c2654ef0 | 243 | #ifdef GUILE_DEBUG |
a1ec6916 | 244 | SCM_DEFINE (scm_wind_chain, "wind-chain", 0, 0, 0, |
1bbd0b84 | 245 | (), |
156149ad MG |
246 | "Return the current wind chain. The wind chain contains all\n" |
247 | "information required by @code{dynamic-wind} to call its\n" | |
248 | "argument thunks when entering/exiting its scope.") | |
1bbd0b84 | 249 | #define FUNC_NAME s_scm_wind_chain |
c2654ef0 MD |
250 | { |
251 | return scm_dynwinds; | |
252 | } | |
1bbd0b84 | 253 | #undef FUNC_NAME |
c2654ef0 MD |
254 | #endif |
255 | ||
2e171178 | 256 | void |
904a077d | 257 | scm_swap_bindings (SCM vars, SCM vals) |
6778caf9 MD |
258 | { |
259 | SCM tmp; | |
260 | while (SCM_NIMP (vals)) | |
261 | { | |
904a077d MV |
262 | tmp = SCM_VARIABLE_REF (SCM_CAR (vars)); |
263 | SCM_VARIABLE_SET (SCM_CAR (vars), SCM_CAR (vals)); | |
6778caf9 | 264 | SCM_SETCAR (vals, tmp); |
904a077d | 265 | vars = SCM_CDR (vars); |
6778caf9 MD |
266 | vals = SCM_CDR (vals); |
267 | } | |
268 | } | |
c2654ef0 | 269 | |
4845bbae | 270 | void |
c014a02e | 271 | scm_dowinds (SCM to, long delta) |
4845bbae | 272 | { |
14578fa4 | 273 | scm_i_dowinds (to, delta, NULL, NULL); |
4845bbae MV |
274 | } |
275 | ||
276 | void | |
14578fa4 | 277 | scm_i_dowinds (SCM to, long delta, void (*turn_func) (void *), void *data) |
0f2d19dd JB |
278 | { |
279 | tail: | |
bc36d050 | 280 | if (scm_is_eq (to, scm_dynwinds)) |
4845bbae MV |
281 | { |
282 | if (turn_func) | |
283 | turn_func (data); | |
284 | } | |
1be6b49c | 285 | else if (delta < 0) |
0f2d19dd JB |
286 | { |
287 | SCM wind_elt; | |
288 | SCM wind_key; | |
289 | ||
14578fa4 | 290 | scm_i_dowinds (SCM_CDR (to), 1 + delta, turn_func, data); |
0f2d19dd | 291 | wind_elt = SCM_CAR (to); |
4845bbae | 292 | |
928e0f42 | 293 | if (FRAME_P (wind_elt)) |
0f2d19dd | 294 | { |
928e0f42 MV |
295 | if (!FRAME_REWINDABLE_P (wind_elt)) |
296 | scm_misc_error ("dowinds", | |
297 | "cannot invoke continuation from this context", | |
298 | SCM_EOL); | |
299 | } | |
300 | else if (WINDER_P (wind_elt)) | |
301 | { | |
302 | if (WINDER_REWIND_P (wind_elt)) | |
303 | WINDER_PROC (wind_elt) (WINDER_DATA (wind_elt)); | |
0f2d19dd JB |
304 | } |
305 | else | |
0f2d19dd | 306 | { |
928e0f42 MV |
307 | wind_key = SCM_CAR (wind_elt); |
308 | /* key = #t | symbol | thunk | list of variables */ | |
309 | if (SCM_NIMP (wind_key)) | |
4845bbae | 310 | { |
928e0f42 | 311 | if (SCM_CONSP (wind_key)) |
4845bbae | 312 | { |
928e0f42 MV |
313 | if (SCM_VARIABLEP (SCM_CAR (wind_key))) |
314 | scm_swap_bindings (wind_key, SCM_CDR (wind_elt)); | |
904a077d | 315 | } |
928e0f42 MV |
316 | else if (SCM_TYP3 (wind_key) == scm_tc3_closure) |
317 | scm_call_0 (wind_key); | |
b3460a50 | 318 | } |
0f2d19dd | 319 | } |
928e0f42 | 320 | |
0f2d19dd JB |
321 | scm_dynwinds = to; |
322 | } | |
323 | else | |
324 | { | |
0f2d19dd JB |
325 | SCM wind_elt; |
326 | SCM wind_key; | |
327 | ||
0f2d19dd JB |
328 | wind_elt = SCM_CAR (scm_dynwinds); |
329 | scm_dynwinds = SCM_CDR (scm_dynwinds); | |
4845bbae | 330 | |
928e0f42 | 331 | if (FRAME_P (wind_elt)) |
0f2d19dd | 332 | { |
928e0f42 MV |
333 | /* Nothing to do. */ |
334 | } | |
335 | else if (WINDER_P (wind_elt)) | |
336 | { | |
337 | if (!WINDER_REWIND_P (wind_elt)) | |
338 | WINDER_PROC (wind_elt) (WINDER_DATA (wind_elt)); | |
0f2d19dd JB |
339 | } |
340 | else | |
0f2d19dd | 341 | { |
928e0f42 MV |
342 | wind_key = SCM_CAR (wind_elt); |
343 | if (SCM_NIMP (wind_key)) | |
4845bbae | 344 | { |
928e0f42 | 345 | if (SCM_CONSP (wind_key)) |
4845bbae | 346 | { |
928e0f42 MV |
347 | if (SCM_VARIABLEP (SCM_CAR (wind_key))) |
348 | scm_swap_bindings (wind_key, SCM_CDR (wind_elt)); | |
904a077d | 349 | } |
928e0f42 MV |
350 | else if (SCM_TYP3 (wind_key) == scm_tc3_closure) |
351 | scm_call_0 (SCM_CDR (wind_elt)); | |
b3460a50 | 352 | } |
0f2d19dd | 353 | } |
928e0f42 | 354 | |
0f2d19dd JB |
355 | delta--; |
356 | goto tail; /* scm_dowinds(to, delta-1); */ | |
357 | } | |
358 | } | |
359 | ||
0f2d19dd JB |
360 | void |
361 | scm_init_dynwind () | |
0f2d19dd | 362 | { |
4845bbae | 363 | tc16_frame = scm_make_smob_type ("frame", 0); |
4845bbae MV |
364 | |
365 | tc16_winder = scm_make_smob_type ("winder", 0); | |
a520e4f0 | 366 | scm_set_smob_mark (tc16_winder, winder_mark); |
4845bbae | 367 | |
a0599745 | 368 | #include "libguile/dynwind.x" |
0f2d19dd | 369 | } |
89e00824 ML |
370 | |
371 | /* | |
372 | Local Variables: | |
373 | c-file-style: "gnu" | |
374 | End: | |
375 | */ |