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 (scm_root_state *root_state)
  94 {
  95   grow_fluids (root_state, SCM_LENGTH(root_state->fluids));
  96 }
  97
  98 static int
  99 print_fluid (SCM exp, SCM port, scm_print_state *pstate)
 100 {
 101     scm_puts ("#<fluid ", port);
 102     scm_intprint (SCM_FLUID_NUM (exp), 10, port);
 103     scm_putc ('>', port);
 104     return 1;
 105 }
 106
 107 static
 108 int next_fluid_num ()
 109 {
 110   int n;
 111 #ifdef USE_THREADS
 112   SCM_THREAD_CRITICAL_SECTION_START;
 113 #endif
 114   n = n_fluids++;
 115 #ifdef USE_THREADS
 116   SCM_THREAD_CRITICAL_SECTION_END;
 117 #endif
 118   return n;
 119 }
 120
 121 SCM_DEFINE (scm_make_fluid, "make-fluid", 0, 0, 0,
 122             (),
 123 "")
 124 #define FUNC_NAME s_scm_make_fluid
 125 {
 126   int n;
 127
 128   SCM_DEFER_INTS;
 129   n = next_fluid_num ();
 130   SCM_RETURN_NEWSMOB (scm_tc16_fluid, n);
 131 }
 132 #undef FUNC_NAME
 133
 134 SCM_DEFINE (scm_fluid_p, "fluid?", 1, 0, 0,
 135             (SCM fl),
 136 "")
 137 #define FUNC_NAME s_scm_fluid_p
 138 {
 139   return SCM_BOOL(SCM_FLUIDP (fl));
 140 }
 141 #undef FUNC_NAME
 142
 143 SCM_DEFINE (scm_fluid_ref, "fluid-ref", 1, 0, 0,
 144             (SCM fl),
 145 "")
 146 #define FUNC_NAME s_scm_fluid_ref
 147 {
 148   int n;
 149
 150   SCM_VALIDATE_FLUID (1,fl);
 151
 152   n = SCM_FLUID_NUM (fl);
 153
 154   if (SCM_LENGTH (scm_root->fluids) <= n)
 155     grow_fluids (scm_root, n+1);
 156   return SCM_VELTS(scm_root->fluids)[n];
 157 }
 158 #undef FUNC_NAME
 159
 160 SCM_DEFINE (scm_fluid_set_x, "fluid-set!", 2, 0, 0,
 161             (SCM fl, SCM val),
 162 "")
 163 #define FUNC_NAME s_scm_fluid_set_x
 164 {
 165   int n;
 166
 167   SCM_VALIDATE_FLUID (1,fl);
 168   n = SCM_FLUID_NUM (fl);
 169
 170   if (SCM_LENGTH (scm_root->fluids) <= n)
 171     grow_fluids (scm_root, n+1);
 172   SCM_VELTS(scm_root->fluids)[n] = val;
 173   return val;
 174 }
 175 #undef FUNC_NAME
 176
 177 void
 178 scm_swap_fluids (SCM fluids, SCM vals)
 179 {
 180   while (SCM_NIMP (fluids))
 181     {
 182       SCM fl = SCM_CAR (fluids);
 183       SCM old_val = scm_fluid_ref (fl);
 184       scm_fluid_set_x (fl, SCM_CAR (vals));
 185       SCM_SETCAR (vals, old_val);
 186       fluids = SCM_CDR (fluids);
 187       vals = SCM_CDR (vals);
 188     }
 189 }
 190
 191 /* Swap the fluid values in reverse order.  This is important when the
 192 same fluid appears multiple times in the fluids list. */
 193
 194 void
 195 scm_swap_fluids_reverse (SCM fluids, SCM vals)
 196 {
 197   if (SCM_NIMP (fluids))
 198     {
 199       SCM fl, old_val;
 200
 201       scm_swap_fluids_reverse (SCM_CDR (fluids), SCM_CDR (vals));
 202       fl = SCM_CAR (fluids);
 203       old_val = scm_fluid_ref (fl);
 204       scm_fluid_set_x (fl, SCM_CAR (vals));
 205       SCM_SETCAR (vals, old_val);
 206     }
 207 }
 208
 209
 210 static SCM
 211 apply_thunk (void *thunk)
 212 {
 213   return scm_apply ((SCM) thunk, SCM_EOL, SCM_EOL);
 214 }
 215
 216 SCM_DEFINE (scm_with_fluids, "with-fluids*", 3, 0, 0,
 217             (SCM fluids, SCM vals, SCM thunk),
 218 "")
 219 #define FUNC_NAME s_scm_with_fluids
 220 {
 221   return scm_internal_with_fluids (fluids, vals, apply_thunk, (void *)thunk);
 222 }
 223 #undef FUNC_NAME
 224
 225 SCM
 226 scm_internal_with_fluids (SCM fluids, SCM vals, SCM (*cproc) (), void *cdata)
 227 {
 228   SCM ans;
 229
 230   int flen = scm_ilength (fluids);
 231   int vlen = scm_ilength (vals);
 232   SCM_ASSERT (flen >= 0, fluids, SCM_ARG1, s_scm_with_fluids);
 233   SCM_ASSERT (vlen >= 0, vals, SCM_ARG2, s_scm_with_fluids);
 234   if (flen != vlen)
 235     scm_out_of_range (s_scm_with_fluids, vals);
 236
 237   scm_swap_fluids (fluids, vals);
 238   scm_dynwinds = scm_acons (fluids, vals, scm_dynwinds);
 239   ans = cproc (cdata);
 240   scm_dynwinds = SCM_CDR (scm_dynwinds);
 241   scm_swap_fluids_reverse (fluids, vals);
 242   return ans;
 243 }
 244
 245
 246
 247 void
 248 scm_init_fluids ()
 249 {
 250   scm_tc16_fluid = scm_make_smob_type_mfpe ("fluid", 0,
 251                                            NULL, NULL, print_fluid, NULL);
 252 #include "fluids.x"
 253 }