libguile/fluids.c

   1 /*      Copyright (C) 1996, 1997 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 #include "_scm.h"
  43 #include "print.h"
  44 #include "smob.h"
  45 #include "genio.h"
  46 #include "dynwind.h"
  47 #include "fluids.h"
  48 #include "alist.h"
  49 #include "eval.h"
  50
  51 #define INITIAL_FLUIDS 10
  52
  53 static volatile int n_fluids;
  54 long scm_tc16_fluid;
  55
  56 SCM
  57 scm_make_initial_fluids ()
  58 {
  59   return scm_make_vector (SCM_MAKINUM (INITIAL_FLUIDS),
  60                           SCM_BOOL_F);
  61 }
  62
  63 static void grow_fluids SCM_P ((scm_root_state *, int new_length));
  64 static void
  65 grow_fluids (root_state, new_length)
  66      scm_root_state *root_state;
  67      int new_length;
  68 {
  69   SCM old_fluids, new_fluids;
  70   int old_length, i;
  71
  72   old_fluids = root_state->fluids;
  73   old_length = SCM_LENGTH (old_fluids);
  74   new_fluids = scm_make_vector (SCM_MAKINUM (new_length), SCM_BOOL_F);
  75   i = 0;
  76   while (i < old_length)
  77     {
  78       SCM_VELTS(new_fluids)[i] = SCM_VELTS(old_fluids)[i];
  79       i++;
  80     }
  81   while (i < new_length)
  82     {
  83       SCM_VELTS(new_fluids)[i] = SCM_BOOL_F;
  84       i++;
  85     }
  86
  87   root_state->fluids = new_fluids;
  88 }
  89
  90 void
  91 scm_copy_fluids (root_state)
  92      scm_root_state *root_state;
  93 {
  94   grow_fluids (root_state, SCM_LENGTH(root_state->fluids));
  95 }
  96
  97 static int print_fluid SCM_P ((SCM exp, SCM port, scm_print_state *pstate));
  98 static int
  99 print_fluid (exp, port, pstate)
 100      SCM exp;
 101      SCM port;
 102      scm_print_state *pstate;
 103 {
 104     scm_puts ("#<fluid ", port);
 105     scm_intprint (SCM_FLUID_NUM (exp), 10, port);
 106     scm_putc ('>', port);
 107     return 1;
 108 }
 109
 110 static
 111 int next_fluid_num ()
 112 {
 113   int n;
 114 #ifdef USE_THREADS
 115   SCM_THREAD_CRITICAL_SECTION_START;
 116 #endif
 117   n = n_fluids++;
 118 #ifdef USE_THREADS
 119   SCM_THREAD_CRITICAL_SECTION_END;
 120 #endif
 121   return n;
 122 }
 123
 124 SCM_PROC (s_make_fluid, "make-fluid", 0, 0, 0, scm_make_fluid);
 125
 126 SCM
 127 scm_make_fluid ()
 128 {
 129   int n;
 130
 131   SCM_DEFER_INTS;
 132   n = next_fluid_num ();
 133   SCM_RETURN_NEWSMOB (scm_tc16_fluid, n);
 134 }
 135
 136 SCM_PROC (s_fluid_p, "fluid?", 1, 0, 0, scm_fluid_p);
 137
 138 SCM
 139 scm_fluid_p (fl)
 140      SCM fl;
 141 {
 142   return (SCM_NIMP (fl) && SCM_FLUIDP (fl))? SCM_BOOL_T : SCM_BOOL_F;
 143 }
 144
 145 SCM_PROC (s_fluid_ref, "fluid-ref", 1, 0, 0, scm_fluid_ref);
 146
 147 SCM
 148 scm_fluid_ref (fl)
 149      SCM fl;
 150 {
 151   int n;
 152
 153   SCM_ASSERT (SCM_NIMP (fl) && SCM_FLUIDP (fl), fl, SCM_ARG1, s_fluid_ref);
 154
 155   n = SCM_FLUID_NUM (fl);
 156
 157   if (SCM_LENGTH (scm_root->fluids) <= n)
 158     grow_fluids (scm_root, n+1);
 159   return SCM_VELTS(scm_root->fluids)[n];
 160 }
 161
 162 SCM_PROC (s_fluid_set_x, "fluid-set!", 2, 0, 0, scm_fluid_set_x);
 163
 164 SCM
 165 scm_fluid_set_x (fl, val)
 166      SCM fl;
 167      SCM val;
 168 {
 169   int n;
 170
 171   SCM_ASSERT (SCM_NIMP (fl) && SCM_FLUIDP (fl), fl, SCM_ARG1, s_fluid_set_x);
 172
 173   n = SCM_FLUID_NUM (fl);
 174
 175   if (SCM_LENGTH (scm_root->fluids) <= n)
 176     grow_fluids (scm_root, n+1);
 177   SCM_VELTS(scm_root->fluids)[n] = val;
 178   return val;
 179 }
 180
 181 void
 182 scm_swap_fluids (fluids, vals)
 183      SCM fluids, vals;
 184 {
 185   while (SCM_NIMP (fluids))
 186     {
 187       SCM fl = SCM_CAR (fluids);
 188       SCM old_val = scm_fluid_ref (fl);
 189       scm_fluid_set_x (fl, SCM_CAR (vals));
 190       SCM_SETCAR (vals, old_val);
 191       fluids = SCM_CDR (fluids);
 192       vals = SCM_CDR (vals);
 193     }
 194 }
 195
 196 /* Swap the fluid values in reverse order.  This is important when the
 197 same fluid appears multiple times in the fluids list. */
 198
 199 void
 200 scm_swap_fluids_reverse (fluids, vals)
 201      SCM fluids, vals;
 202 {
 203   if (SCM_NIMP (fluids))
 204     {
 205       SCM fl, old_val;
 206
 207       scm_swap_fluids_reverse (SCM_CDR (fluids), SCM_CDR (vals));
 208       fl = SCM_CAR (fluids);
 209       old_val = scm_fluid_ref (fl);
 210       scm_fluid_set_x (fl, SCM_CAR (vals));
 211       SCM_SETCAR (vals, old_val);
 212     }
 213 }
 214
 215 SCM_PROC (s_with_fluids, "with-fluids*", 3, 0, 0, scm_with_fluids);
 216
 217 SCM
 218 scm_internal_with_fluids (fluids, vals, cproc, cdata)
 219      SCM fluids, vals;
 220      SCM (*cproc) ();
 221      void *cdata;
 222 {
 223   SCM ans;
 224
 225   int flen = scm_ilength (fluids);
 226   int vlen = scm_ilength (vals);
 227   SCM_ASSERT (flen >= 0, fluids, SCM_ARG1, s_with_fluids);
 228   SCM_ASSERT (vlen >= 0, vals, SCM_ARG2, s_with_fluids);
 229   if (flen != vlen)
 230     scm_out_of_range (s_with_fluids, vals);
 231
 232   scm_swap_fluids (fluids, vals);
 233   scm_dynwinds = scm_acons (fluids, vals, scm_dynwinds);
 234   ans = cproc (cdata);
 235   scm_dynwinds = SCM_CDR (scm_dynwinds);
 236   scm_swap_fluids_reverse (fluids, vals);
 237   return ans;
 238 }
 239
 240 static SCM
 241 apply_thunk (void *thunk)
 242 {
 243   return scm_apply ((SCM) thunk, SCM_EOL, SCM_EOL);
 244 }
 245
 246 SCM
 247 scm_with_fluids (fluids, vals, thunk)
 248      SCM fluids, vals, thunk;
 249 {
 250   return scm_internal_with_fluids (fluids, vals, apply_thunk, (void *)thunk);
 251 }
 252
 253 void
 254 scm_init_fluids ()
 255 {
 256   scm_tc16_fluid = scm_make_smob_type_mfpe ("fluid", 0,
 257                                            NULL, NULL, print_fluid, NULL);
 258 #include "fluids.x"
 259 }