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 <assert.h>
  43
  44 #include "_scm.h"
  45 #include "print.h"
  46 #include "smob.h"
  47 #include "dynwind.h"
  48 #include "fluids.h"
  49 #include "alist.h"
  50 #include "eval.h"
  51
  52 #define INITIAL_FLUIDS 10
  53
  54 static volatile int n_fluids;
  55 long scm_tc16_fluid;
  56
  57 SCM
  58 scm_make_initial_fluids ()
  59 {
  60   return scm_make_vector (SCM_MAKINUM (INITIAL_FLUIDS),
  61                           SCM_BOOL_F, SCM_BOOL_F);
  62 }
  63
  64 static void grow_fluids SCM_P ((scm_root_state *, int new_length));
  65 static void
  66 grow_fluids (root_state, new_length)
  67      scm_root_state *root_state;
  68      int new_length;
  69 {
  70   SCM old_fluids, new_fluids;
  71   int old_length, i;
  72
  73   old_fluids = root_state->fluids;
  74   assert (SCM_NIMP (old_fluids) && SCM_VECTORP (old_fluids));
  75   old_length = SCM_LENGTH (old_fluids);
  76   assert (old_length <= new_length);
  77   new_fluids = scm_make_vector (SCM_MAKINUM (new_length),
  78                                 SCM_BOOL_F, SCM_BOOL_F);
  79   i = 0;
  80   while (i < old_length)
  81     {
  82       SCM_VELTS(new_fluids)[i] = SCM_VELTS(old_fluids)[i];
  83       i++;
  84     }
  85   while (i < new_length)
  86     {
  87       SCM_VELTS(new_fluids)[i] = SCM_BOOL_F;
  88       i++;
  89     }
  90
  91   root_state->fluids = new_fluids;
  92 }
  93
  94 void
  95 scm_copy_fluids (root_state)
  96      scm_root_state *root_state;
  97 {
  98   grow_fluids (root_state, SCM_LENGTH(root_state->fluids));
  99 }
 100
 101 static int print_fluid SCM_P ((SCM exp, SCM port, scm_print_state *pstate));
 102 static int
 103 print_fluid (exp, port, pstate)
 104      SCM exp;
 105      SCM port;
 106      scm_print_state *pstate;
 107 {
 108     scm_puts ("#<fluid ", port);
 109     scm_intprint (SCM_FLUID_NUM (exp), 10, port);
 110     scm_putc ('>', port);
 111     return 1;
 112 }
 113
 114 static scm_smobfuns fluid_smob = {
 115     scm_mark0,
 116     scm_free0,
 117     print_fluid
 118 };
 119
 120 static
 121 int next_fluid_num ()
 122 {
 123   int n;
 124 #ifdef USE_THREADS
 125   SCM_THREAD_CRITICAL_SECTION_START;
 126 #endif
 127   n = n_fluids++;
 128 #ifdef USE_THREADS
 129   SCM_THREAD_CRITICAL_SECTION_END;
 130 #endif
 131   return n;
 132 }
 133
 134 SCM_PROC (s_make_fluid, "make-fluid", 0, 0, 0, scm_make_fluid);
 135
 136 SCM
 137 scm_make_fluid ()
 138 {
 139   SCM z;
 140   int n;
 141
 142   SCM_DEFER_INTS;
 143   n = next_fluid_num ();
 144   SCM_NEWCELL (z);
 145   SCM_SETCAR (z, scm_tc16_fluid);
 146   SCM_SETCDR (z, n);
 147   SCM_ALLOW_INTS;
 148
 149   return z;
 150 }
 151
 152 SCM_PROC (s_fluid_p, "fluid?", 1, 0, 0, scm_fluid_p);
 153
 154 SCM
 155 scm_fluid_p (fl)
 156      SCM fl;
 157 {
 158   return (SCM_NIMP (fl) && SCM_FLUIDP (fl))? SCM_BOOL_T : SCM_BOOL_F;
 159 }
 160
 161 SCM_PROC (s_fluid_ref, "fluid-ref", 1, 0, 0, scm_fluid_ref);
 162
 163 SCM
 164 scm_fluid_ref (fl)
 165      SCM fl;
 166 {
 167   int n;
 168
 169   SCM_ASSERT (SCM_NIMP (fl) && SCM_FLUIDP (fl), fl, SCM_ARG1, s_fluid_ref);
 170
 171   n = SCM_FLUID_NUM (fl);
 172   assert (n >= 0 && n < n_fluids);
 173
 174   if (SCM_LENGTH (scm_root->fluids) <= n)
 175     grow_fluids (scm_root, n+1);
 176   return SCM_VELTS(scm_root->fluids)[n];
 177 }
 178
 179 SCM_PROC (s_fluid_set_x, "fluid-set!", 2, 0, 0, scm_fluid_set_x);
 180
 181 SCM
 182 scm_fluid_set_x (fl, val)
 183      SCM fl;
 184      SCM val;
 185 {
 186   int n;
 187
 188   SCM_ASSERT (SCM_NIMP (fl) && SCM_FLUIDP (fl), fl, SCM_ARG1, s_fluid_set_x);
 189
 190   n = SCM_FLUID_NUM (fl);
 191   assert (n >= 0 && n < n_fluids);
 192
 193   if (SCM_LENGTH (scm_root->fluids) <= n)
 194     grow_fluids (scm_root, n+1);
 195   SCM_VELTS(scm_root->fluids)[n] = val;
 196   return val;
 197 }
 198
 199 void
 200 scm_swap_fluids (fluids, vals)
 201      SCM fluids, vals;
 202 {
 203   while (SCM_NIMP (fluids))
 204     {
 205       SCM fl = SCM_CAR (fluids);
 206       SCM old_val = scm_fluid_ref (fl);
 207       scm_fluid_set_x (fl, SCM_CAR (vals));
 208       SCM_SETCAR (vals, old_val);
 209       fluids = SCM_CDR (fluids);
 210       vals = SCM_CDR (vals);
 211     }
 212 }
 213
 214 /* Swap the fluid values in reverse order.  This is important when the
 215 same fluid appears multiple times in the fluids list. */
 216
 217 void
 218 scm_swap_fluids_reverse (fluids, vals)
 219      SCM fluids, vals;
 220 {
 221   if (SCM_NIMP (fluids))
 222     {
 223       SCM fl, old_val;
 224
 225       scm_swap_fluids_reverse (SCM_CDR (fluids), SCM_CDR (vals));
 226       fl = SCM_CAR (fluids);
 227       old_val = scm_fluid_ref (fl);
 228       scm_fluid_set_x (fl, SCM_CAR (vals));
 229       SCM_SETCAR (vals, old_val);
 230     }
 231 }
 232
 233 SCM_PROC (s_with_fluids, "with-fluids*", 3, 0, 0, scm_with_fluids);
 234
 235 SCM
 236 scm_internal_with_fluids (fluids, vals, cproc, cdata)
 237      SCM fluids, vals;
 238      SCM (*cproc) ();
 239      void *cdata;
 240 {
 241   SCM ans;
 242
 243   int flen = scm_ilength (fluids);
 244   int vlen = scm_ilength (vals);
 245   SCM_ASSERT (flen >= 0, fluids, SCM_ARG1, s_with_fluids);
 246   SCM_ASSERT (vlen >= 0, vals, SCM_ARG2, s_with_fluids);
 247   if (flen != vlen)
 248     scm_out_of_range (s_with_fluids, vals);
 249
 250   scm_swap_fluids (fluids, vals);
 251   scm_dynwinds = scm_acons (fluids, vals, scm_dynwinds);
 252   ans = cproc (cdata);
 253   scm_dynwinds = SCM_CDR (scm_dynwinds);
 254   scm_swap_fluids_reverse (fluids, vals);
 255   return ans;
 256 }
 257
 258 static SCM
 259 apply_thunk (void *thunk)
 260 {
 261   return scm_apply ((SCM) thunk, SCM_EOL, SCM_EOL);
 262 }
 263
 264 SCM
 265 scm_with_fluids (fluids, vals, thunk)
 266      SCM fluids, vals, thunk;
 267 {
 268   return scm_internal_with_fluids (fluids, vals, apply_thunk, (void *)thunk);
 269 }
 270
 271 void
 272 scm_init_fluids ()
 273 {
 274   scm_tc16_fluid = scm_newsmob(&fluid_smob);
 275 #include "fluids.x"
 276 }