libguile/feature.c

   1 /*      Copyright (C) 1995, 1996, 1998, 1999 Free Software Foundation, Inc.
   2  *
   3  * This program is free software; you can redistribute it and/or modify
   4  * it under the terms of the GNU General Public License as published by
   5  * the Free Software Foundation; either version 2, or (at your option)
   6  * any later version.
   7  *
   8  * This program 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
  11  * GNU General Public License for more details.
  12  *
  13  * You should have received a copy of the GNU General Public License
  14  * along with this software; see the file COPYING.  If not, write to
  15  * the Free Software Foundation, Inc., 59 Temple Place, Suite 330,
  16  * Boston, MA 02111-1307 USA
  17  *
  18  * As a special exception, the Free Software Foundation gives permission
  19  * for additional uses of the text contained in its release of GUILE.
  20  *
  21  * The exception is that, if you link the GUILE library with other files
  22  * to produce an executable, this does not by itself cause the
  23  * resulting executable to be covered by the GNU General Public License.
  24  * Your use of that executable is in no way restricted on account of
  25  * linking the GUILE library code into it.
  26  *
  27  * This exception does not however invalidate any other reasons why
  28  * the executable file might be covered by the GNU General Public License.
  29  *
  30  * This exception applies only to the code released by the
  31  * Free Software Foundation under the name GUILE.  If you copy
  32  * code from other Free Software Foundation releases into a copy of
  33  * GUILE, as the General Public License permits, the exception does
  34  * not apply to the code that you add in this way.  To avoid misleading
  35  * anyone as to the status of such modified files, you must delete
  36  * this exception notice from them.
  37  *
  38  * If you write modifications of your own for GUILE, it is your choice
  39  * whether to permit this exception to apply to your modifications.
  40  * If you do not wish that, delete this exception notice.  */
  41
  42 /* Software engineering face-lift by Greg J. Badros, 11-Dec-1999,
  43    gjb@cs.washington.edu, http://www.cs.washington.edu/homes/gjb */
  44
  45 \f
  46
  47 #include <stdio.h>
  48 #include "_scm.h"
  49
  50 #include "eval.h"
  51 #include "procprop.h"
  52 #include "smob.h"
  53
  54 #include "scm_validate.h"
  55 #include "feature.h"
  56
  57 #ifdef HAVE_STRING_H
  58 #include <string.h>
  59 #endif
  60 \f
  61
  62 static SCM *scm_loc_features;
  63
  64 void
  65 scm_add_feature (const char *str)
  66 {
  67   *scm_loc_features = scm_cons (SCM_CAR (scm_intern (str, strlen (str))),
  68                                 *scm_loc_features);
  69 }
  70
  71
  72 \f
  73
  74 GUILE_PROC(scm_program_arguments, "program-arguments", 0, 0, 0,
  75            (),
  76 "")
  77 #define FUNC_NAME s_scm_program_arguments
  78 {
  79   return scm_progargs;
  80 }
  81 #undef FUNC_NAME
  82
  83 /* Set the value returned by program-arguments, given ARGC and ARGV.
  84
  85    If FIRST is non-zero, make it the first element; we do this in
  86    situations where other code (like getopt) has parsed out a few
  87    arguments, but we still want the script name to be the first
  88    element.  */
  89 void
  90 scm_set_program_arguments (int argc, char **argv, char *first)
  91 {
  92   scm_progargs = scm_makfromstrs (argc, argv);
  93   if (first)
  94     scm_progargs = scm_cons (scm_makfrom0str (first), scm_progargs);
  95 }
  96
  97
  98 \f
  99 /* Hooks
 100  *
 101  * A hook is basically a list of procedures to be called at well defined
 102  * points in time.
 103  *
 104  * Hook name and arity are not full members of this type and therefore
 105  * lack accessors.  They are added to aid debugging and are not
 106  * intended to be used in programs.
 107  *
 108  */
 109
 110 long scm_tc16_hook;
 111
 112
 113 static SCM
 114 make_hook (SCM name, SCM n_args, const char *subr)
 115 {
 116   int n;
 117   SCM_ASSERT (SCM_FALSEP (name) || (SCM_NIMP (name) && SCM_SYMBOLP (name)),
 118               name,
 119               SCM_ARG1,
 120               subr);
 121   if (SCM_UNBNDP (n_args))
 122     n = 0;
 123   else
 124     {
 125       SCM_ASSERT (SCM_INUMP (n_args), n_args, SCM_ARGn, subr);
 126       n = SCM_INUM (n_args);
 127     }
 128   SCM_ASSERT (n >= 0 && n <= 16, n_args, SCM_OUTOFRANGE, subr);
 129   SCM_RETURN_NEWSMOB (scm_tc16_hook + (n << 16), SCM_LIST1 (name));
 130 }
 131
 132
 133 static int
 134 print_hook (SCM hook, SCM port, scm_print_state *pstate)
 135 {
 136   SCM ls, name;
 137   scm_puts ("#<hook ", port);
 138   if (SCM_NFALSEP (SCM_HOOK_NAME (hook)))
 139     {
 140       scm_iprin1 (SCM_HOOK_NAME (hook), port, pstate);
 141       scm_putc (' ', port);
 142     }
 143   scm_intprint (SCM_HOOK_ARITY (hook), 10, port);
 144   scm_putc (' ', port);
 145   scm_intprint (hook, 16, port);
 146   ls = SCM_HOOK_PROCEDURES (hook);
 147   while (SCM_NIMP (ls))
 148     {
 149       scm_putc (' ', port);
 150       name = scm_procedure_name (SCM_CAR (ls));
 151       if (SCM_NFALSEP (name))
 152         scm_iprin1 (name, port, pstate);
 153       else
 154         scm_putc ('?', port);
 155       ls = SCM_CDR (ls);
 156     }
 157   scm_putc ('>', port);
 158   return 1;
 159 }
 160
 161
 162 SCM
 163 scm_create_hook (const char* name, int n_args)
 164 {
 165   SCM vcell = scm_sysintern0 (name);
 166   SCM hook = make_hook (SCM_CAR (vcell), SCM_MAKINUM (n_args),
 167                         "scm_create_hook");
 168   SCM_SETCDR (vcell, hook);
 169   scm_protect_object (vcell);
 170   return hook;
 171 }
 172
 173
 174 /* This function is deprecated.  It will be removed in next release. */
 175 SCM
 176 scm_make_named_hook (const char* name, int n_args)
 177 {
 178   return scm_create_hook (name, n_args);
 179 }
 180
 181
 182 GUILE_PROC (scm_make_hook_with_name, "make-hook-with-name", 1, 1, 0,
 183             (SCM name, SCM n_args),
 184 "")
 185 #define FUNC_NAME s_scm_make_hook_with_name
 186 {
 187   return make_hook (name, n_args, FUNC_NAME);
 188 }
 189 #undef FUNC_NAME
 190
 191
 192 GUILE_PROC (scm_make_hook, "make-hook", 0, 1, 0,
 193             (SCM n_args),
 194 "")
 195 #define FUNC_NAME s_scm_make_hook
 196 {
 197   return make_hook (SCM_BOOL_F, n_args, FUNC_NAME);
 198 }
 199 #undef FUNC_NAME
 200
 201
 202 GUILE_PROC (scm_hook_p, "hook?", 1, 0, 0,
 203             (SCM x),
 204 "")
 205 #define FUNC_NAME s_scm_hook_p
 206 {
 207   return SCM_BOOL(SCM_NIMP (x) && SCM_HOOKP (x));
 208 }
 209 #undef FUNC_NAME
 210
 211
 212 GUILE_PROC (scm_hook_empty_p, "hook-empty?", 1, 0, 0,
 213             (SCM hook),
 214 "")
 215 #define FUNC_NAME s_scm_hook_empty_p
 216 {
 217   SCM_VALIDATE_HOOK(1,hook);
 218   return SCM_BOOL(SCM_NULLP (SCM_HOOK_PROCEDURES (hook)));
 219 }
 220 #undef FUNC_NAME
 221
 222
 223 GUILE_PROC (scm_add_hook_x, "add-hook!", 2, 1, 0,
 224             (SCM hook, SCM proc, SCM append_p),
 225 "")
 226 #define FUNC_NAME s_scm_add_hook_x
 227 {
 228   SCM arity, rest;
 229   int n_args;
 230   SCM_VALIDATE_HOOK(1,hook);
 231   SCM_ASSERT (SCM_NFALSEP (arity = scm_i_procedure_arity (proc)),
 232               proc, SCM_ARG2, FUNC_NAME);
 233   n_args = SCM_HOOK_ARITY (hook);
 234   if (SCM_INUM (SCM_CAR (arity)) > n_args
 235       || (SCM_FALSEP (SCM_CADDR (arity))
 236           && (SCM_INUM (SCM_CAR (arity)) + SCM_INUM (SCM_CADR (arity))
 237               < n_args)))
 238     scm_misc_error (FUNC_NAME,
 239                     "This hook requires %s arguments",
 240                     SCM_LIST1 (SCM_MAKINUM (SCM_HOOK_ARITY (hook))));
 241   rest = scm_delq_x (proc, SCM_HOOK_PROCEDURES (hook));
 242   SCM_SET_HOOK_PROCEDURES (hook,
 243                            (!SCM_UNBNDP (append_p) && SCM_NFALSEP (append_p)
 244                             ? scm_append_x (SCM_LIST2 (rest, SCM_LIST1 (proc)))
 245                             : scm_cons (proc, rest)));
 246   return SCM_UNSPECIFIED;
 247 }
 248 #undef FUNC_NAME
 249
 250
 251 GUILE_PROC (scm_remove_hook_x, "remove-hook!", 2, 0, 0,
 252             (SCM hook, SCM proc),
 253 "")
 254 #define FUNC_NAME s_scm_remove_hook_x
 255 {
 256   SCM_VALIDATE_HOOK(1,hook);
 257   SCM_SET_HOOK_PROCEDURES (hook,
 258                            scm_delq_x (proc, SCM_HOOK_PROCEDURES (hook)));
 259   return SCM_UNSPECIFIED;
 260 }
 261 #undef FUNC_NAME
 262
 263
 264 GUILE_PROC (scm_reset_hook_x, "reset-hook!", 1, 0, 0,
 265             (SCM hook),
 266 "")
 267 #define FUNC_NAME s_scm_reset_hook_x
 268 {
 269   SCM_VALIDATE_HOOK(1,hook);
 270   SCM_SET_HOOK_PROCEDURES (hook, SCM_EOL);
 271   return SCM_UNSPECIFIED;
 272 }
 273 #undef FUNC_NAME
 274
 275
 276 GUILE_PROC (scm_run_hook, "run-hook", 1, 0, 1,
 277             (SCM hook, SCM args),
 278 "")
 279 #define FUNC_NAME s_scm_run_hook
 280 {
 281   SCM_VALIDATE_HOOK(1,hook);
 282   if (SCM_UNBNDP (args))
 283     args = SCM_EOL;
 284   if (scm_ilength (args) != SCM_HOOK_ARITY (hook))
 285     scm_misc_error (FUNC_NAME,
 286                     "This hook requires %s arguments",
 287                     SCM_LIST1 (SCM_MAKINUM (SCM_HOOK_ARITY (hook))));
 288   scm_c_run_hook (hook, args);
 289   return SCM_UNSPECIFIED;
 290 }
 291 #undef FUNC_NAME
 292
 293
 294 void
 295 scm_c_run_hook (SCM hook, SCM args)
 296 {
 297   SCM procs = SCM_HOOK_PROCEDURES (hook);
 298   while (SCM_NIMP (procs))
 299     {
 300       scm_apply (SCM_CAR (procs), args, SCM_EOL);
 301       procs = SCM_CDR (procs);
 302     }
 303 }
 304
 305
 306 GUILE_PROC (scm_hook_to_list, "hook->list", 1, 0, 0,
 307             (SCM hook),
 308 "")
 309 #define FUNC_NAME s_scm_hook_to_list
 310 {
 311   SCM_VALIDATE_HOOK(1,hook);
 312   return scm_list_copy (SCM_HOOK_PROCEDURES (hook));
 313 }
 314 #undef FUNC_NAME
 315
 316
 317 \f
 318
 319 void
 320 scm_init_feature()
 321 {
 322   scm_loc_features = SCM_CDRLOC (scm_sysintern ("*features*", SCM_EOL));
 323 #ifdef SCM_RECKLESS
 324   scm_add_feature("reckless");
 325 #endif
 326 #ifndef _Windows
 327   scm_add_feature("system");
 328 #endif
 329 #ifdef vms
 330   scm_add_feature(s_ed);
 331 #endif
 332 #ifdef SICP
 333   scm_add_feature("sicp");
 334 #endif
 335 #ifndef GO32
 336   scm_add_feature("char-ready?");
 337 #endif
 338 #ifndef CHEAP_CONTINUATIONS
 339   scm_add_feature ("full-continuation");
 340 #endif
 341 #ifdef USE_THREADS
 342   scm_add_feature ("threads");
 343 #endif
 344
 345   scm_sysintern ("char-code-limit", SCM_MAKINUM (SCM_CHAR_CODE_LIMIT));
 346
 347   scm_tc16_hook = scm_make_smob_type ("hook", 0);
 348   scm_set_smob_mark (scm_tc16_hook, scm_markcdr);
 349   scm_set_smob_print (scm_tc16_hook, print_hook);
 350
 351 #include "feature.x"
 352 }