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