libguile/variable.c

   1 /*      Copyright (C) 1995,1996, 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 \f
  42
  43 #include <stdio.h>
  44 #include "_scm.h"
  45 #include "eq.h"
  46 #include "genio.h"
  47 #include "smob.h"
  48
  49 #include "variable.h"
  50 \f
  51
  52 static scm_sizet free_var SCM_P ((SCM obj));
  53
  54 static scm_sizet
  55 free_var (obj)
  56      SCM obj;
  57 {
  58   return 0;
  59 }
  60
  61
  62
  63 static int prin_var SCM_P ((SCM exp, SCM port, scm_print_state *pstate));
  64
  65 static int
  66 prin_var (exp, port, pstate)
  67      SCM exp;
  68      SCM port;
  69      scm_print_state *pstate;
  70 {
  71   scm_puts ("#<variable ", port);
  72   scm_intprint(exp, 16, port);
  73   {
  74     SCM val_cell;
  75     val_cell = SCM_CDR(exp);
  76     if (SCM_CAR (val_cell) != SCM_UNDEFINED)
  77       {
  78         scm_puts (" name: ", port);
  79         scm_iprin1 (SCM_CAR (val_cell), port, pstate);
  80       }
  81     scm_puts (" binding: ", port);
  82     scm_iprin1 (SCM_CDR (val_cell), port, pstate);
  83   }
  84   scm_putc('>', port);
  85   return 1;
  86 }
  87
  88
  89 static SCM scm_markvar SCM_P ((SCM ptr));
  90
  91 static SCM
  92 scm_markvar (ptr)
  93      SCM ptr;
  94 {
  95   return SCM_CDR (ptr);
  96 }
  97
  98 static SCM var_equal SCM_P ((SCM var1, SCM var2));
  99
 100 static SCM
 101 var_equal (var1, var2)
 102      SCM var1;
 103      SCM var2;
 104 {
 105   return scm_equal_p (SCM_CDR (var1), SCM_CDR (var2));
 106 }
 107
 108 int scm_tc16_variable;
 109 static scm_smobfuns variable_smob = {scm_markvar, free_var, prin_var, var_equal};
 110 \f
 111
 112 static SCM anonymous_variable_sym;
 113
 114
 115 static SCM make_vcell_variable SCM_P ((SCM vcell));
 116
 117 static SCM
 118 make_vcell_variable (vcell)
 119      SCM vcell;
 120 {
 121   SCM answer;
 122   SCM_NEWCELL(answer);
 123   SCM_REDEFER_INTS;
 124   SCM_SETCAR (answer, scm_tc16_variable);
 125   SCM_SETCDR (answer, vcell);
 126   SCM_REALLOW_INTS;
 127   return answer;
 128 }
 129
 130 SCM_PROC(s_make_variable, "make-variable", 1, 1, 0, scm_make_variable);
 131
 132 SCM
 133 scm_make_variable (init, name_hint)
 134      SCM init;
 135      SCM name_hint;
 136 {
 137   SCM val_cell;
 138
 139   if (name_hint == SCM_UNDEFINED)
 140     name_hint = anonymous_variable_sym;
 141
 142   SCM_NEWCELL(val_cell);
 143   SCM_DEFER_INTS;
 144   SCM_SETCAR (val_cell, name_hint);
 145   SCM_SETCDR (val_cell, init);
 146   SCM_ALLOW_INTS;
 147   return make_vcell_variable (val_cell);
 148 }
 149
 150
 151 SCM_PROC(s_make_undefined_variable, "make-undefined-variable", 0, 1, 0, scm_make_undefined_variable);
 152
 153 SCM
 154 scm_make_undefined_variable (name_hint)
 155      SCM name_hint;
 156 {
 157   SCM vcell;
 158
 159   if (name_hint == SCM_UNDEFINED)
 160     name_hint = anonymous_variable_sym;
 161
 162   SCM_NEWCELL (vcell);
 163   SCM_DEFER_INTS;
 164   SCM_SETCAR (vcell, name_hint);
 165   SCM_SETCDR (vcell, SCM_UNDEFINED);
 166   SCM_ALLOW_INTS;
 167   return make_vcell_variable (vcell);
 168 }
 169
 170
 171 SCM_PROC(s_variable_p, "variable?", 1, 0, 0, scm_variable_p);
 172
 173 SCM
 174 scm_variable_p (obj)
 175      SCM obj;
 176 {
 177   return ( (SCM_NIMP(obj) && SCM_VARIABLEP (obj))
 178           ? SCM_BOOL_T
 179           : SCM_BOOL_F);
 180 }
 181
 182
 183 SCM_PROC(s_variable_ref, "variable-ref", 1, 0, 0, scm_variable_ref);
 184
 185 SCM
 186 scm_variable_ref (var)
 187      SCM var;
 188 {
 189   SCM_ASSERT (SCM_NIMP(var) && SCM_VARIABLEP(var), var, SCM_ARG1, s_variable_ref);
 190   return SCM_CDR (SCM_CDR (var));
 191 }
 192
 193
 194
 195 SCM_PROC(s_variable_set_x, "variable-set!", 2, 0, 0, scm_variable_set_x);
 196
 197 SCM
 198 scm_variable_set_x (var, val)
 199      SCM var;
 200      SCM val;
 201 {
 202   SCM_ASSERT (SCM_NIMP(var) && SCM_VARIABLEP (var), var, SCM_ARG1, s_variable_set_x);
 203   SCM_SETCDR (SCM_CDR (var), val);
 204   return SCM_UNSPECIFIED;
 205 }
 206
 207
 208 SCM_PROC(s_builtin_variable, "builtin-variable", 1, 0, 0, scm_builtin_variable);
 209
 210 SCM
 211 scm_builtin_variable (name)
 212      SCM name;
 213 {
 214   SCM vcell;
 215   SCM var_slot;
 216
 217   SCM_ASSERT (SCM_NIMP (name) && SCM_SYMBOLP (name), name, SCM_ARG1, s_builtin_variable);
 218   vcell = scm_sym2vcell (name, SCM_BOOL_F, SCM_BOOL_T);
 219   if (vcell == SCM_BOOL_F)
 220     return SCM_BOOL_F;
 221
 222   scm_intern_symbol (scm_symhash_vars, name);
 223   var_slot = scm_sym2ovcell (name, scm_symhash_vars);
 224
 225   SCM_DEFER_INTS;
 226   if (   SCM_IMP (SCM_CDR (var_slot))
 227       || (SCM_VARVCELL (var_slot) != vcell))
 228     SCM_SETCDR (var_slot, make_vcell_variable (vcell));
 229   SCM_ALLOW_INTS;
 230
 231   return SCM_CDR (var_slot);
 232 }
 233
 234
 235 SCM_PROC(s_variable_bound_p, "variable-bound?", 1, 0, 0, scm_variable_bound_p);
 236
 237 SCM
 238 scm_variable_bound_p (var)
 239      SCM var;
 240 {
 241   SCM_ASSERT (SCM_NIMP(var) && SCM_VARIABLEP (var), var, SCM_ARG1, s_variable_bound_p);
 242   return (SCM_UNBNDP (SCM_CDR (SCM_VARVCELL (var)))
 243           ? SCM_BOOL_F
 244           : SCM_BOOL_T);
 245 }
 246
 247
 248
 249
 250 void
 251 scm_init_variable ()
 252 {
 253   scm_tc16_variable = scm_newsmob (&variable_smob);
 254   anonymous_variable_sym = SCM_CAR (scm_sysintern ("anonymous-variable", SCM_UNDEFINED));
 255 #include "variable.x"
 256 }
 257