Commit | Line | Data |
---|---|---|
dbb605f5 | 1 | /* Copyright (C) 1995,1996,1998,1999,2000,2001, 2003, 2004, 2006, 2008 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 | |
92205699 | 15 | * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA |
73be1d9e | 16 | */ |
1bbd0b84 | 17 | |
1bbd0b84 | 18 | |
0f2d19dd JB |
19 | \f |
20 | ||
dbb605f5 LC |
21 | #ifdef HAVE_CONFIG_H |
22 | # include <config.h> | |
23 | #endif | |
24 | ||
4845bbae MV |
25 | #include <assert.h> |
26 | ||
a0599745 MD |
27 | #include "libguile/_scm.h" |
28 | #include "libguile/eval.h" | |
29 | #include "libguile/alist.h" | |
30 | #include "libguile/fluids.h" | |
31 | #include "libguile/ports.h" | |
32 | #include "libguile/smob.h" | |
0f2d19dd | 33 | |
a0599745 | 34 | #include "libguile/dynwind.h" |
0f2d19dd JB |
35 | \f |
36 | ||
37 | /* {Dynamic wind} | |
b3460a50 MV |
38 | |
39 | Things that can be on the wind list: | |
40 | ||
4845bbae MV |
41 | #<frame> |
42 | #<winder> | |
b3460a50 MV |
43 | (enter-proc . leave-proc) dynamic-wind |
44 | (tag . jmpbuf) catch | |
43e01b1e | 45 | (tag . pre-unwind-data) throw-handler / lazy-catch |
b3460a50 MV |
46 | tag is either a symbol or a boolean |
47 | ||
b3460a50 | 48 | */ |
0f2d19dd JB |
49 | |
50 | ||
51 | ||
3b3b36dd | 52 | SCM_DEFINE (scm_dynamic_wind, "dynamic-wind", 3, 0, 0, |
1e6808ea MG |
53 | (SCM in_guard, SCM thunk, SCM out_guard), |
54 | "All three arguments must be 0-argument procedures.\n" | |
55 | "@var{in_guard} is called, then @var{thunk}, then\n" | |
56 | "@var{out_guard}.\n" | |
57 | "\n" | |
58 | "If, any time during the execution of @var{thunk}, the\n" | |
59 | "continuation of the @code{dynamic_wind} expression is escaped\n" | |
60 | "non-locally, @var{out_guard} is called. If the continuation of\n" | |
61 | "the dynamic-wind is re-entered, @var{in_guard} is called. Thus\n" | |
62 | "@var{in_guard} and @var{out_guard} may be called any number of\n" | |
63 | "times.\n" | |
64 | "@lisp\n" | |
b380b885 | 65 | "(define x 'normal-binding)\n" |
1e6808ea | 66 | "@result{} x\n" |
9401323e | 67 | "(define a-cont (call-with-current-continuation\n" |
b380b885 MD |
68 | " (lambda (escape)\n" |
69 | " (let ((old-x x))\n" | |
70 | " (dynamic-wind\n" | |
71 | " ;; in-guard:\n" | |
72 | " ;;\n" | |
1e6808ea MG |
73 | " (lambda () (set! x 'special-binding))\n" |
74 | "\n" | |
b380b885 MD |
75 | " ;; thunk\n" |
76 | " ;;\n" | |
77 | " (lambda () (display x) (newline)\n" | |
78 | " (call-with-current-continuation escape)\n" | |
79 | " (display x) (newline)\n" | |
1e6808ea MG |
80 | " x)\n" |
81 | "\n" | |
b380b885 MD |
82 | " ;; out-guard:\n" |
83 | " ;;\n" | |
1e6808ea MG |
84 | " (lambda () (set! x old-x)))))))\n" |
85 | "\n" | |
9401323e | 86 | ";; Prints:\n" |
b380b885 MD |
87 | "special-binding\n" |
88 | ";; Evaluates to:\n" | |
1e6808ea | 89 | "@result{} a-cont\n" |
b380b885 | 90 | "x\n" |
1e6808ea | 91 | "@result{} normal-binding\n" |
b380b885 MD |
92 | "(a-cont #f)\n" |
93 | ";; Prints:\n" | |
94 | "special-binding\n" | |
95 | ";; Evaluates to:\n" | |
1e6808ea | 96 | "@result{} a-cont ;; the value of the (define a-cont...)\n" |
b380b885 | 97 | "x\n" |
1e6808ea | 98 | "@result{} normal-binding\n" |
b380b885 MD |
99 | "a-cont\n" |
100 | "@result{} special-binding\n" | |
1e6808ea | 101 | "@end lisp") |
1bbd0b84 | 102 | #define FUNC_NAME s_scm_dynamic_wind |
0f2d19dd | 103 | { |
9de87eea | 104 | SCM ans, old_winds; |
7888309b | 105 | SCM_ASSERT (scm_is_true (scm_thunk_p (out_guard)), |
1e6808ea | 106 | out_guard, |
1bbd0b84 | 107 | SCM_ARG3, FUNC_NAME); |
fdc28395 | 108 | scm_call_0 (in_guard); |
9de87eea MV |
109 | old_winds = scm_i_dynwinds (); |
110 | scm_i_set_dynwinds (scm_acons (in_guard, out_guard, old_winds)); | |
fdc28395 | 111 | ans = scm_call_0 (thunk); |
9de87eea | 112 | scm_i_set_dynwinds (old_winds); |
fdc28395 | 113 | scm_call_0 (out_guard); |
0f2d19dd JB |
114 | return ans; |
115 | } | |
1bbd0b84 | 116 | #undef FUNC_NAME |
0f2d19dd | 117 | |
3346a90f | 118 | SCM |
92c2555f MV |
119 | scm_internal_dynamic_wind (scm_t_guard before, |
120 | scm_t_inner inner, | |
121 | scm_t_guard after, | |
3346a90f MD |
122 | void *inner_data, |
123 | void *guard_data) | |
124 | { | |
4845bbae MV |
125 | SCM ans; |
126 | ||
661ae7ab MV |
127 | scm_dynwind_begin (SCM_F_DYNWIND_REWINDABLE); |
128 | scm_dynwind_rewind_handler (before, guard_data, SCM_F_WIND_EXPLICITLY); | |
129 | scm_dynwind_unwind_handler (after, guard_data, SCM_F_WIND_EXPLICITLY); | |
3346a90f | 130 | ans = inner (inner_data); |
661ae7ab | 131 | scm_dynwind_end (); |
3346a90f MD |
132 | return ans; |
133 | } | |
1cc91f1b | 134 | |
4845bbae MV |
135 | /* Frames and winders. */ |
136 | ||
137 | static scm_t_bits tc16_frame; | |
138 | #define FRAME_P(f) SCM_SMOB_PREDICATE (tc16_frame, (f)) | |
139 | ||
f5710d53 MV |
140 | #define FRAME_F_REWINDABLE (1 << 0) |
141 | #define FRAME_REWINDABLE_P(f) (SCM_SMOB_FLAGS(f) & FRAME_F_REWINDABLE) | |
4845bbae MV |
142 | |
143 | static scm_t_bits tc16_winder; | |
14578fa4 | 144 | #define WINDER_P(w) SCM_SMOB_PREDICATE (tc16_winder, (w)) |
f5710d53 MV |
145 | #define WINDER_PROC(w) ((void (*)(void *))SCM_SMOB_DATA (w)) |
146 | #define WINDER_DATA(w) ((void *)SCM_SMOB_DATA_2 (w)) | |
4845bbae | 147 | |
f5710d53 MV |
148 | #define WINDER_F_EXPLICIT (1 << 0) |
149 | #define WINDER_F_REWIND (1 << 1) | |
150 | #define WINDER_F_MARK (1 << 2) | |
151 | #define WINDER_EXPLICIT_P(w) (SCM_SMOB_FLAGS(w) & WINDER_F_EXPLICIT) | |
152 | #define WINDER_REWIND_P(w) (SCM_SMOB_FLAGS(w) & WINDER_F_REWIND) | |
153 | #define WINDER_MARK_P(w) (SCM_SMOB_FLAGS(w) & WINDER_F_MARK) | |
4845bbae MV |
154 | |
155 | void | |
661ae7ab | 156 | scm_dynwind_begin (scm_t_dynwind_flags flags) |
4845bbae MV |
157 | { |
158 | SCM f; | |
f5710d53 | 159 | SCM_NEWSMOB (f, tc16_frame, 0); |
661ae7ab | 160 | if (flags & SCM_F_DYNWIND_REWINDABLE) |
f5710d53 | 161 | SCM_SET_SMOB_FLAGS (f, FRAME_F_REWINDABLE); |
9de87eea | 162 | scm_i_set_dynwinds (scm_cons (f, scm_i_dynwinds ())); |
4845bbae MV |
163 | } |
164 | ||
165 | void | |
661ae7ab | 166 | scm_dynwind_end (void) |
4845bbae | 167 | { |
9de87eea MV |
168 | SCM winds; |
169 | ||
0888de4f MV |
170 | /* Unwind upto and including the next frame entry. We can only |
171 | encounter #<winder> entries on the way. | |
4845bbae MV |
172 | */ |
173 | ||
9de87eea MV |
174 | winds = scm_i_dynwinds (); |
175 | while (scm_is_pair (winds)) | |
4845bbae | 176 | { |
9de87eea MV |
177 | SCM entry = SCM_CAR (winds); |
178 | winds = SCM_CDR (winds); | |
179 | ||
180 | scm_i_set_dynwinds (winds); | |
0888de4f MV |
181 | |
182 | if (FRAME_P (entry)) | |
183 | return; | |
184 | ||
185 | assert (WINDER_P (entry)); | |
186 | if (!WINDER_REWIND_P (entry) && WINDER_EXPLICIT_P (entry)) | |
187 | WINDER_PROC(entry) (WINDER_DATA (entry)); | |
4845bbae MV |
188 | } |
189 | ||
190 | assert (0); | |
191 | } | |
192 | ||
193 | void | |
661ae7ab MV |
194 | scm_dynwind_unwind_handler (void (*proc) (void *), void *data, |
195 | scm_t_wind_flags flags) | |
4845bbae MV |
196 | { |
197 | SCM w; | |
f5710d53 MV |
198 | SCM_NEWSMOB2 (w, tc16_winder, (scm_t_bits) proc, (scm_t_bits) data); |
199 | if (flags & SCM_F_WIND_EXPLICITLY) | |
200 | SCM_SET_SMOB_FLAGS (w, WINDER_F_EXPLICIT); | |
9de87eea | 201 | scm_i_set_dynwinds (scm_cons (w, scm_i_dynwinds ())); |
4845bbae MV |
202 | } |
203 | ||
204 | void | |
661ae7ab MV |
205 | scm_dynwind_rewind_handler (void (*proc) (void *), void *data, |
206 | scm_t_wind_flags flags) | |
4845bbae MV |
207 | { |
208 | SCM w; | |
f5710d53 MV |
209 | SCM_NEWSMOB2 (w, tc16_winder, (scm_t_bits) proc, (scm_t_bits) data); |
210 | SCM_SET_SMOB_FLAGS (w, WINDER_F_REWIND); | |
9de87eea | 211 | scm_i_set_dynwinds (scm_cons (w, scm_i_dynwinds ())); |
a520e4f0 MV |
212 | if (flags & SCM_F_WIND_EXPLICITLY) |
213 | proc (data); | |
214 | } | |
215 | ||
216 | void | |
661ae7ab MV |
217 | scm_dynwind_unwind_handler_with_scm (void (*proc) (SCM), SCM data, |
218 | scm_t_wind_flags flags) | |
a520e4f0 MV |
219 | { |
220 | SCM w; | |
221 | scm_t_bits fl = ((flags&SCM_F_WIND_EXPLICITLY)? WINDER_F_EXPLICIT : 0); | |
f5710d53 MV |
222 | SCM_NEWSMOB2 (w, tc16_winder, (scm_t_bits) proc, SCM_UNPACK (data)); |
223 | SCM_SET_SMOB_FLAGS (w, fl | WINDER_F_MARK); | |
9de87eea | 224 | scm_i_set_dynwinds (scm_cons (w, scm_i_dynwinds ())); |
a520e4f0 MV |
225 | } |
226 | ||
227 | void | |
661ae7ab MV |
228 | scm_dynwind_rewind_handler_with_scm (void (*proc) (SCM), SCM data, |
229 | scm_t_wind_flags flags) | |
a520e4f0 MV |
230 | { |
231 | SCM w; | |
f5710d53 MV |
232 | SCM_NEWSMOB2 (w, tc16_winder, (scm_t_bits) proc, SCM_UNPACK (data)); |
233 | SCM_SET_SMOB_FLAGS (w, WINDER_F_REWIND | WINDER_F_MARK); | |
9de87eea | 234 | scm_i_set_dynwinds (scm_cons (w, scm_i_dynwinds ())); |
a520e4f0 | 235 | if (flags & SCM_F_WIND_EXPLICITLY) |
4845bbae MV |
236 | proc (data); |
237 | } | |
238 | ||
6d5649b7 | 239 | void |
661ae7ab | 240 | scm_dynwind_free (void *mem) |
6d5649b7 | 241 | { |
661ae7ab | 242 | scm_dynwind_unwind_handler (free, mem, SCM_F_WIND_EXPLICITLY); |
6d5649b7 MV |
243 | } |
244 | ||
c2654ef0 | 245 | #ifdef GUILE_DEBUG |
a1ec6916 | 246 | SCM_DEFINE (scm_wind_chain, "wind-chain", 0, 0, 0, |
1bbd0b84 | 247 | (), |
156149ad MG |
248 | "Return the current wind chain. The wind chain contains all\n" |
249 | "information required by @code{dynamic-wind} to call its\n" | |
250 | "argument thunks when entering/exiting its scope.") | |
1bbd0b84 | 251 | #define FUNC_NAME s_scm_wind_chain |
c2654ef0 | 252 | { |
9de87eea | 253 | return scm_i_dynwinds (); |
c2654ef0 | 254 | } |
1bbd0b84 | 255 | #undef FUNC_NAME |
c2654ef0 MD |
256 | #endif |
257 | ||
2e171178 | 258 | void |
904a077d | 259 | scm_swap_bindings (SCM vars, SCM vals) |
6778caf9 MD |
260 | { |
261 | SCM tmp; | |
262 | while (SCM_NIMP (vals)) | |
263 | { | |
904a077d MV |
264 | tmp = SCM_VARIABLE_REF (SCM_CAR (vars)); |
265 | SCM_VARIABLE_SET (SCM_CAR (vars), SCM_CAR (vals)); | |
6778caf9 | 266 | SCM_SETCAR (vals, tmp); |
904a077d | 267 | vars = SCM_CDR (vars); |
6778caf9 MD |
268 | vals = SCM_CDR (vals); |
269 | } | |
270 | } | |
c2654ef0 | 271 | |
4845bbae | 272 | void |
c014a02e | 273 | scm_dowinds (SCM to, long delta) |
4845bbae | 274 | { |
14578fa4 | 275 | scm_i_dowinds (to, delta, NULL, NULL); |
4845bbae MV |
276 | } |
277 | ||
278 | void | |
14578fa4 | 279 | scm_i_dowinds (SCM to, long delta, void (*turn_func) (void *), void *data) |
0f2d19dd JB |
280 | { |
281 | tail: | |
9de87eea | 282 | if (scm_is_eq (to, scm_i_dynwinds ())) |
4845bbae MV |
283 | { |
284 | if (turn_func) | |
285 | turn_func (data); | |
286 | } | |
1be6b49c | 287 | else if (delta < 0) |
0f2d19dd JB |
288 | { |
289 | SCM wind_elt; | |
290 | SCM wind_key; | |
291 | ||
14578fa4 | 292 | scm_i_dowinds (SCM_CDR (to), 1 + delta, turn_func, data); |
0f2d19dd | 293 | wind_elt = SCM_CAR (to); |
4845bbae | 294 | |
928e0f42 | 295 | if (FRAME_P (wind_elt)) |
0f2d19dd | 296 | { |
928e0f42 MV |
297 | if (!FRAME_REWINDABLE_P (wind_elt)) |
298 | scm_misc_error ("dowinds", | |
299 | "cannot invoke continuation from this context", | |
300 | SCM_EOL); | |
301 | } | |
302 | else if (WINDER_P (wind_elt)) | |
303 | { | |
304 | if (WINDER_REWIND_P (wind_elt)) | |
305 | WINDER_PROC (wind_elt) (WINDER_DATA (wind_elt)); | |
0f2d19dd JB |
306 | } |
307 | else | |
0f2d19dd | 308 | { |
928e0f42 MV |
309 | wind_key = SCM_CAR (wind_elt); |
310 | /* key = #t | symbol | thunk | list of variables */ | |
311 | if (SCM_NIMP (wind_key)) | |
4845bbae | 312 | { |
d2e53ed6 | 313 | if (scm_is_pair (wind_key)) |
4845bbae | 314 | { |
928e0f42 MV |
315 | if (SCM_VARIABLEP (SCM_CAR (wind_key))) |
316 | scm_swap_bindings (wind_key, SCM_CDR (wind_elt)); | |
904a077d | 317 | } |
928e0f42 MV |
318 | else if (SCM_TYP3 (wind_key) == scm_tc3_closure) |
319 | scm_call_0 (wind_key); | |
b3460a50 | 320 | } |
0f2d19dd | 321 | } |
928e0f42 | 322 | |
9de87eea | 323 | scm_i_set_dynwinds (to); |
0f2d19dd JB |
324 | } |
325 | else | |
326 | { | |
9de87eea | 327 | SCM wind; |
0f2d19dd JB |
328 | SCM wind_elt; |
329 | SCM wind_key; | |
330 | ||
9de87eea MV |
331 | wind = scm_i_dynwinds (); |
332 | wind_elt = SCM_CAR (wind); | |
333 | scm_i_set_dynwinds (SCM_CDR (wind)); | |
4845bbae | 334 | |
928e0f42 | 335 | if (FRAME_P (wind_elt)) |
0f2d19dd | 336 | { |
928e0f42 MV |
337 | /* Nothing to do. */ |
338 | } | |
339 | else if (WINDER_P (wind_elt)) | |
340 | { | |
341 | if (!WINDER_REWIND_P (wind_elt)) | |
342 | WINDER_PROC (wind_elt) (WINDER_DATA (wind_elt)); | |
0f2d19dd JB |
343 | } |
344 | else | |
0f2d19dd | 345 | { |
928e0f42 MV |
346 | wind_key = SCM_CAR (wind_elt); |
347 | if (SCM_NIMP (wind_key)) | |
4845bbae | 348 | { |
d2e53ed6 | 349 | if (scm_is_pair (wind_key)) |
4845bbae | 350 | { |
928e0f42 MV |
351 | if (SCM_VARIABLEP (SCM_CAR (wind_key))) |
352 | scm_swap_bindings (wind_key, SCM_CDR (wind_elt)); | |
904a077d | 353 | } |
928e0f42 MV |
354 | else if (SCM_TYP3 (wind_key) == scm_tc3_closure) |
355 | scm_call_0 (SCM_CDR (wind_elt)); | |
b3460a50 | 356 | } |
0f2d19dd | 357 | } |
928e0f42 | 358 | |
0f2d19dd JB |
359 | delta--; |
360 | goto tail; /* scm_dowinds(to, delta-1); */ | |
361 | } | |
362 | } | |
363 | ||
0f2d19dd JB |
364 | void |
365 | scm_init_dynwind () | |
0f2d19dd | 366 | { |
4845bbae | 367 | tc16_frame = scm_make_smob_type ("frame", 0); |
4845bbae MV |
368 | |
369 | tc16_winder = scm_make_smob_type ("winder", 0); | |
370 | ||
a0599745 | 371 | #include "libguile/dynwind.x" |
0f2d19dd | 372 | } |
89e00824 ML |
373 | |
374 | /* | |
375 | Local Variables: | |
376 | c-file-style: "gnu" | |
377 | End: | |
378 | */ |