Commit | Line | Data |
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dbb605f5 | 1 | /* Copyright (C) 1995,1996,1998,1999,2000,2001, 2003, 2004, 2006, 2008 Free Software Foundation, Inc. |
0f2d19dd | 2 | * |
73be1d9e | 3 | * This library is free software; you can redistribute it and/or |
53befeb7 NJ |
4 | * modify it under the terms of the GNU Lesser General Public License |
5 | * as published by the Free Software Foundation; either version 3 of | |
6 | * the License, or (at your option) any later version. | |
0f2d19dd | 7 | * |
53befeb7 NJ |
8 | * This library is distributed in the hope that it will be useful, but |
9 | * WITHOUT ANY WARRANTY; without even the implied warranty of | |
73be1d9e MV |
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 | |
53befeb7 NJ |
15 | * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA |
16 | * 02110-1301 USA | |
73be1d9e | 17 | */ |
1bbd0b84 | 18 | |
1bbd0b84 | 19 | |
0f2d19dd JB |
20 | \f |
21 | ||
dbb605f5 LC |
22 | #ifdef HAVE_CONFIG_H |
23 | # include <config.h> | |
24 | #endif | |
25 | ||
4845bbae MV |
26 | #include <assert.h> |
27 | ||
a0599745 MD |
28 | #include "libguile/_scm.h" |
29 | #include "libguile/eval.h" | |
30 | #include "libguile/alist.h" | |
31 | #include "libguile/fluids.h" | |
32 | #include "libguile/ports.h" | |
33 | #include "libguile/smob.h" | |
0f2d19dd | 34 | |
a0599745 | 35 | #include "libguile/dynwind.h" |
0f2d19dd JB |
36 | \f |
37 | ||
38 | /* {Dynamic wind} | |
b3460a50 MV |
39 | |
40 | Things that can be on the wind list: | |
41 | ||
4845bbae MV |
42 | #<frame> |
43 | #<winder> | |
b3460a50 MV |
44 | (enter-proc . leave-proc) dynamic-wind |
45 | (tag . jmpbuf) catch | |
43e01b1e | 46 | (tag . pre-unwind-data) throw-handler / lazy-catch |
b3460a50 MV |
47 | tag is either a symbol or a boolean |
48 | ||
b3460a50 | 49 | */ |
0f2d19dd JB |
50 | |
51 | ||
52 | ||
3b3b36dd | 53 | SCM_DEFINE (scm_dynamic_wind, "dynamic-wind", 3, 0, 0, |
1e6808ea MG |
54 | (SCM in_guard, SCM thunk, SCM out_guard), |
55 | "All three arguments must be 0-argument procedures.\n" | |
56 | "@var{in_guard} is called, then @var{thunk}, then\n" | |
57 | "@var{out_guard}.\n" | |
58 | "\n" | |
59 | "If, any time during the execution of @var{thunk}, the\n" | |
60 | "continuation of the @code{dynamic_wind} expression is escaped\n" | |
61 | "non-locally, @var{out_guard} is called. If the continuation of\n" | |
62 | "the dynamic-wind is re-entered, @var{in_guard} is called. Thus\n" | |
63 | "@var{in_guard} and @var{out_guard} may be called any number of\n" | |
64 | "times.\n" | |
65 | "@lisp\n" | |
b380b885 | 66 | "(define x 'normal-binding)\n" |
1e6808ea | 67 | "@result{} x\n" |
9401323e | 68 | "(define a-cont (call-with-current-continuation\n" |
b380b885 MD |
69 | " (lambda (escape)\n" |
70 | " (let ((old-x x))\n" | |
71 | " (dynamic-wind\n" | |
72 | " ;; in-guard:\n" | |
73 | " ;;\n" | |
1e6808ea MG |
74 | " (lambda () (set! x 'special-binding))\n" |
75 | "\n" | |
b380b885 MD |
76 | " ;; thunk\n" |
77 | " ;;\n" | |
78 | " (lambda () (display x) (newline)\n" | |
79 | " (call-with-current-continuation escape)\n" | |
80 | " (display x) (newline)\n" | |
1e6808ea MG |
81 | " x)\n" |
82 | "\n" | |
b380b885 MD |
83 | " ;; out-guard:\n" |
84 | " ;;\n" | |
1e6808ea MG |
85 | " (lambda () (set! x old-x)))))))\n" |
86 | "\n" | |
9401323e | 87 | ";; Prints:\n" |
b380b885 MD |
88 | "special-binding\n" |
89 | ";; Evaluates to:\n" | |
1e6808ea | 90 | "@result{} a-cont\n" |
b380b885 | 91 | "x\n" |
1e6808ea | 92 | "@result{} normal-binding\n" |
b380b885 MD |
93 | "(a-cont #f)\n" |
94 | ";; Prints:\n" | |
95 | "special-binding\n" | |
96 | ";; Evaluates to:\n" | |
1e6808ea | 97 | "@result{} a-cont ;; the value of the (define a-cont...)\n" |
b380b885 | 98 | "x\n" |
1e6808ea | 99 | "@result{} normal-binding\n" |
b380b885 MD |
100 | "a-cont\n" |
101 | "@result{} special-binding\n" | |
1e6808ea | 102 | "@end lisp") |
1bbd0b84 | 103 | #define FUNC_NAME s_scm_dynamic_wind |
0f2d19dd | 104 | { |
9de87eea | 105 | SCM ans, old_winds; |
7888309b | 106 | SCM_ASSERT (scm_is_true (scm_thunk_p (out_guard)), |
1e6808ea | 107 | out_guard, |
1bbd0b84 | 108 | SCM_ARG3, FUNC_NAME); |
fdc28395 | 109 | scm_call_0 (in_guard); |
9de87eea MV |
110 | old_winds = scm_i_dynwinds (); |
111 | scm_i_set_dynwinds (scm_acons (in_guard, out_guard, old_winds)); | |
fdc28395 | 112 | ans = scm_call_0 (thunk); |
9de87eea | 113 | scm_i_set_dynwinds (old_winds); |
fdc28395 | 114 | scm_call_0 (out_guard); |
0f2d19dd JB |
115 | return ans; |
116 | } | |
1bbd0b84 | 117 | #undef FUNC_NAME |
0f2d19dd | 118 | |
3346a90f | 119 | SCM |
92c2555f MV |
120 | scm_internal_dynamic_wind (scm_t_guard before, |
121 | scm_t_inner inner, | |
122 | scm_t_guard after, | |
3346a90f MD |
123 | void *inner_data, |
124 | void *guard_data) | |
125 | { | |
4845bbae MV |
126 | SCM ans; |
127 | ||
661ae7ab MV |
128 | scm_dynwind_begin (SCM_F_DYNWIND_REWINDABLE); |
129 | scm_dynwind_rewind_handler (before, guard_data, SCM_F_WIND_EXPLICITLY); | |
130 | scm_dynwind_unwind_handler (after, guard_data, SCM_F_WIND_EXPLICITLY); | |
3346a90f | 131 | ans = inner (inner_data); |
661ae7ab | 132 | scm_dynwind_end (); |
3346a90f MD |
133 | return ans; |
134 | } | |
1cc91f1b | 135 | |
4845bbae MV |
136 | /* Frames and winders. */ |
137 | ||
138 | static scm_t_bits tc16_frame; | |
139 | #define FRAME_P(f) SCM_SMOB_PREDICATE (tc16_frame, (f)) | |
140 | ||
f5710d53 MV |
141 | #define FRAME_F_REWINDABLE (1 << 0) |
142 | #define FRAME_REWINDABLE_P(f) (SCM_SMOB_FLAGS(f) & FRAME_F_REWINDABLE) | |
4845bbae MV |
143 | |
144 | static scm_t_bits tc16_winder; | |
14578fa4 | 145 | #define WINDER_P(w) SCM_SMOB_PREDICATE (tc16_winder, (w)) |
f5710d53 MV |
146 | #define WINDER_PROC(w) ((void (*)(void *))SCM_SMOB_DATA (w)) |
147 | #define WINDER_DATA(w) ((void *)SCM_SMOB_DATA_2 (w)) | |
4845bbae | 148 | |
f5710d53 MV |
149 | #define WINDER_F_EXPLICIT (1 << 0) |
150 | #define WINDER_F_REWIND (1 << 1) | |
151 | #define WINDER_F_MARK (1 << 2) | |
152 | #define WINDER_EXPLICIT_P(w) (SCM_SMOB_FLAGS(w) & WINDER_F_EXPLICIT) | |
153 | #define WINDER_REWIND_P(w) (SCM_SMOB_FLAGS(w) & WINDER_F_REWIND) | |
154 | #define WINDER_MARK_P(w) (SCM_SMOB_FLAGS(w) & WINDER_F_MARK) | |
4845bbae MV |
155 | |
156 | void | |
98241dc5 | 157 | scm_dynwind_begin (scm_t_dynwind_flags flags) |
4845bbae MV |
158 | { |
159 | SCM f; | |
f5710d53 | 160 | SCM_NEWSMOB (f, tc16_frame, 0); |
661ae7ab | 161 | if (flags & SCM_F_DYNWIND_REWINDABLE) |
f5710d53 | 162 | SCM_SET_SMOB_FLAGS (f, FRAME_F_REWINDABLE); |
9de87eea | 163 | scm_i_set_dynwinds (scm_cons (f, scm_i_dynwinds ())); |
4845bbae MV |
164 | } |
165 | ||
166 | void | |
661ae7ab | 167 | scm_dynwind_end (void) |
4845bbae | 168 | { |
9de87eea MV |
169 | SCM winds; |
170 | ||
0888de4f MV |
171 | /* Unwind upto and including the next frame entry. We can only |
172 | encounter #<winder> entries on the way. | |
4845bbae MV |
173 | */ |
174 | ||
9de87eea MV |
175 | winds = scm_i_dynwinds (); |
176 | while (scm_is_pair (winds)) | |
4845bbae | 177 | { |
9de87eea MV |
178 | SCM entry = SCM_CAR (winds); |
179 | winds = SCM_CDR (winds); | |
180 | ||
181 | scm_i_set_dynwinds (winds); | |
0888de4f MV |
182 | |
183 | if (FRAME_P (entry)) | |
184 | return; | |
185 | ||
186 | assert (WINDER_P (entry)); | |
187 | if (!WINDER_REWIND_P (entry) && WINDER_EXPLICIT_P (entry)) | |
188 | WINDER_PROC(entry) (WINDER_DATA (entry)); | |
4845bbae MV |
189 | } |
190 | ||
191 | assert (0); | |
192 | } | |
193 | ||
194 | void | |
98241dc5 NJ |
195 | scm_dynwind_unwind_handler (void (*proc) (void *), void *data, |
196 | scm_t_wind_flags flags) | |
4845bbae MV |
197 | { |
198 | SCM w; | |
f5710d53 MV |
199 | SCM_NEWSMOB2 (w, tc16_winder, (scm_t_bits) proc, (scm_t_bits) data); |
200 | if (flags & SCM_F_WIND_EXPLICITLY) | |
201 | SCM_SET_SMOB_FLAGS (w, WINDER_F_EXPLICIT); | |
9de87eea | 202 | scm_i_set_dynwinds (scm_cons (w, scm_i_dynwinds ())); |
4845bbae MV |
203 | } |
204 | ||
205 | void | |
98241dc5 NJ |
206 | scm_dynwind_rewind_handler (void (*proc) (void *), void *data, |
207 | scm_t_wind_flags flags) | |
4845bbae MV |
208 | { |
209 | SCM w; | |
f5710d53 MV |
210 | SCM_NEWSMOB2 (w, tc16_winder, (scm_t_bits) proc, (scm_t_bits) data); |
211 | SCM_SET_SMOB_FLAGS (w, WINDER_F_REWIND); | |
9de87eea | 212 | scm_i_set_dynwinds (scm_cons (w, scm_i_dynwinds ())); |
a520e4f0 MV |
213 | if (flags & SCM_F_WIND_EXPLICITLY) |
214 | proc (data); | |
215 | } | |
216 | ||
217 | void | |
98241dc5 NJ |
218 | scm_dynwind_unwind_handler_with_scm (void (*proc) (SCM), SCM data, |
219 | scm_t_wind_flags flags) | |
a520e4f0 MV |
220 | { |
221 | SCM w; | |
222 | scm_t_bits fl = ((flags&SCM_F_WIND_EXPLICITLY)? WINDER_F_EXPLICIT : 0); | |
f5710d53 MV |
223 | SCM_NEWSMOB2 (w, tc16_winder, (scm_t_bits) proc, SCM_UNPACK (data)); |
224 | SCM_SET_SMOB_FLAGS (w, fl | WINDER_F_MARK); | |
9de87eea | 225 | scm_i_set_dynwinds (scm_cons (w, scm_i_dynwinds ())); |
a520e4f0 MV |
226 | } |
227 | ||
228 | void | |
98241dc5 NJ |
229 | scm_dynwind_rewind_handler_with_scm (void (*proc) (SCM), SCM data, |
230 | scm_t_wind_flags flags) | |
a520e4f0 MV |
231 | { |
232 | SCM w; | |
f5710d53 MV |
233 | SCM_NEWSMOB2 (w, tc16_winder, (scm_t_bits) proc, SCM_UNPACK (data)); |
234 | SCM_SET_SMOB_FLAGS (w, WINDER_F_REWIND | WINDER_F_MARK); | |
9de87eea | 235 | scm_i_set_dynwinds (scm_cons (w, scm_i_dynwinds ())); |
a520e4f0 | 236 | if (flags & SCM_F_WIND_EXPLICITLY) |
4845bbae MV |
237 | proc (data); |
238 | } | |
239 | ||
6d5649b7 | 240 | void |
661ae7ab | 241 | scm_dynwind_free (void *mem) |
6d5649b7 | 242 | { |
661ae7ab | 243 | scm_dynwind_unwind_handler (free, mem, SCM_F_WIND_EXPLICITLY); |
6d5649b7 MV |
244 | } |
245 | ||
c2654ef0 | 246 | #ifdef GUILE_DEBUG |
a1ec6916 | 247 | SCM_DEFINE (scm_wind_chain, "wind-chain", 0, 0, 0, |
1bbd0b84 | 248 | (), |
156149ad MG |
249 | "Return the current wind chain. The wind chain contains all\n" |
250 | "information required by @code{dynamic-wind} to call its\n" | |
251 | "argument thunks when entering/exiting its scope.") | |
1bbd0b84 | 252 | #define FUNC_NAME s_scm_wind_chain |
c2654ef0 | 253 | { |
9de87eea | 254 | return scm_i_dynwinds (); |
c2654ef0 | 255 | } |
1bbd0b84 | 256 | #undef FUNC_NAME |
c2654ef0 MD |
257 | #endif |
258 | ||
2e171178 | 259 | void |
904a077d | 260 | scm_swap_bindings (SCM vars, SCM vals) |
6778caf9 MD |
261 | { |
262 | SCM tmp; | |
263 | while (SCM_NIMP (vals)) | |
264 | { | |
904a077d MV |
265 | tmp = SCM_VARIABLE_REF (SCM_CAR (vars)); |
266 | SCM_VARIABLE_SET (SCM_CAR (vars), SCM_CAR (vals)); | |
6778caf9 | 267 | SCM_SETCAR (vals, tmp); |
904a077d | 268 | vars = SCM_CDR (vars); |
6778caf9 MD |
269 | vals = SCM_CDR (vals); |
270 | } | |
271 | } | |
c2654ef0 | 272 | |
4845bbae | 273 | void |
c014a02e | 274 | scm_dowinds (SCM to, long delta) |
4845bbae | 275 | { |
14578fa4 | 276 | scm_i_dowinds (to, delta, NULL, NULL); |
4845bbae MV |
277 | } |
278 | ||
279 | void | |
14578fa4 | 280 | scm_i_dowinds (SCM to, long delta, void (*turn_func) (void *), void *data) |
0f2d19dd JB |
281 | { |
282 | tail: | |
9de87eea | 283 | if (scm_is_eq (to, scm_i_dynwinds ())) |
4845bbae MV |
284 | { |
285 | if (turn_func) | |
286 | turn_func (data); | |
287 | } | |
1be6b49c | 288 | else if (delta < 0) |
0f2d19dd JB |
289 | { |
290 | SCM wind_elt; | |
291 | SCM wind_key; | |
292 | ||
14578fa4 | 293 | scm_i_dowinds (SCM_CDR (to), 1 + delta, turn_func, data); |
0f2d19dd | 294 | wind_elt = SCM_CAR (to); |
4845bbae | 295 | |
928e0f42 | 296 | if (FRAME_P (wind_elt)) |
0f2d19dd | 297 | { |
928e0f42 MV |
298 | if (!FRAME_REWINDABLE_P (wind_elt)) |
299 | scm_misc_error ("dowinds", | |
300 | "cannot invoke continuation from this context", | |
301 | SCM_EOL); | |
302 | } | |
303 | else if (WINDER_P (wind_elt)) | |
304 | { | |
305 | if (WINDER_REWIND_P (wind_elt)) | |
306 | WINDER_PROC (wind_elt) (WINDER_DATA (wind_elt)); | |
0f2d19dd JB |
307 | } |
308 | else | |
0f2d19dd | 309 | { |
928e0f42 MV |
310 | wind_key = SCM_CAR (wind_elt); |
311 | /* key = #t | symbol | thunk | list of variables */ | |
312 | if (SCM_NIMP (wind_key)) | |
4845bbae | 313 | { |
d2e53ed6 | 314 | if (scm_is_pair (wind_key)) |
4845bbae | 315 | { |
928e0f42 MV |
316 | if (SCM_VARIABLEP (SCM_CAR (wind_key))) |
317 | scm_swap_bindings (wind_key, SCM_CDR (wind_elt)); | |
904a077d | 318 | } |
5a963489 | 319 | else if (scm_is_true (scm_thunk_p (wind_key))) |
928e0f42 | 320 | scm_call_0 (wind_key); |
b3460a50 | 321 | } |
0f2d19dd | 322 | } |
928e0f42 | 323 | |
9de87eea | 324 | scm_i_set_dynwinds (to); |
0f2d19dd JB |
325 | } |
326 | else | |
327 | { | |
9de87eea | 328 | SCM wind; |
0f2d19dd JB |
329 | SCM wind_elt; |
330 | SCM wind_key; | |
331 | ||
9de87eea MV |
332 | wind = scm_i_dynwinds (); |
333 | wind_elt = SCM_CAR (wind); | |
334 | scm_i_set_dynwinds (SCM_CDR (wind)); | |
4845bbae | 335 | |
928e0f42 | 336 | if (FRAME_P (wind_elt)) |
0f2d19dd | 337 | { |
928e0f42 MV |
338 | /* Nothing to do. */ |
339 | } | |
340 | else if (WINDER_P (wind_elt)) | |
341 | { | |
342 | if (!WINDER_REWIND_P (wind_elt)) | |
343 | WINDER_PROC (wind_elt) (WINDER_DATA (wind_elt)); | |
0f2d19dd JB |
344 | } |
345 | else | |
0f2d19dd | 346 | { |
928e0f42 MV |
347 | wind_key = SCM_CAR (wind_elt); |
348 | if (SCM_NIMP (wind_key)) | |
4845bbae | 349 | { |
d2e53ed6 | 350 | if (scm_is_pair (wind_key)) |
4845bbae | 351 | { |
928e0f42 MV |
352 | if (SCM_VARIABLEP (SCM_CAR (wind_key))) |
353 | scm_swap_bindings (wind_key, SCM_CDR (wind_elt)); | |
904a077d | 354 | } |
5a963489 | 355 | else if (scm_is_true (scm_thunk_p (wind_key))) |
928e0f42 | 356 | scm_call_0 (SCM_CDR (wind_elt)); |
b3460a50 | 357 | } |
0f2d19dd | 358 | } |
928e0f42 | 359 | |
0f2d19dd JB |
360 | delta--; |
361 | goto tail; /* scm_dowinds(to, delta-1); */ | |
362 | } | |
363 | } | |
364 | ||
0f2d19dd JB |
365 | void |
366 | scm_init_dynwind () | |
0f2d19dd | 367 | { |
4845bbae | 368 | tc16_frame = scm_make_smob_type ("frame", 0); |
4845bbae MV |
369 | |
370 | tc16_winder = scm_make_smob_type ("winder", 0); | |
371 | ||
a0599745 | 372 | #include "libguile/dynwind.x" |
0f2d19dd | 373 | } |
89e00824 ML |
374 | |
375 | /* | |
376 | Local Variables: | |
377 | c-file-style: "gnu" | |
378 | End: | |
379 | */ |