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   if (SCM_GC8MARKP (ptr))
  96     return SCM_BOOL_F;
  97   SCM_SETGC8MARK (ptr);
  98   return SCM_CDR (ptr);
  99 }
 100
 101 static SCM var_equal SCM_P ((SCM var1, SCM var2));
 102
 103 static SCM
 104 var_equal (var1, var2)
 105      SCM var1;
 106      SCM var2;
 107 {
 108   return scm_equal_p (SCM_CDR (var1), SCM_CDR (var2));
 109 }
 110
 111 int scm_tc16_variable;
 112 static scm_smobfuns variable_smob = {scm_markvar, free_var, prin_var, var_equal};
 113 \f
 114
 115 static SCM anonymous_variable_sym;
 116
 117
 118 static SCM make_vcell_variable SCM_P ((SCM vcell));
 119
 120 static SCM
 121 make_vcell_variable (vcell)
 122      SCM vcell;
 123 {
 124   SCM answer;
 125   SCM_NEWCELL(answer);
 126   SCM_REDEFER_INTS;
 127   SCM_SETCAR (answer, scm_tc16_variable);
 128   SCM_SETCDR (answer, vcell);
 129   SCM_REALLOW_INTS;
 130   return answer;
 131 }
 132
 133 SCM_PROC(s_make_variable, "make-variable", 1, 1, 0, scm_make_variable);
 134
 135 SCM
 136 scm_make_variable (init, name_hint)
 137      SCM init;
 138      SCM name_hint;
 139 {
 140   SCM val_cell;
 141
 142   if (name_hint == SCM_UNDEFINED)
 143     name_hint = anonymous_variable_sym;
 144
 145   SCM_NEWCELL(val_cell);
 146   SCM_DEFER_INTS;
 147   SCM_SETCAR (val_cell, name_hint);
 148   SCM_SETCDR (val_cell, init);
 149   SCM_ALLOW_INTS;
 150   return make_vcell_variable (val_cell);
 151 }
 152
 153
 154 SCM_PROC(s_make_undefined_variable, "make-undefined-variable", 0, 1, 0, scm_make_undefined_variable);
 155
 156 SCM
 157 scm_make_undefined_variable (name_hint)
 158      SCM name_hint;
 159 {
 160   SCM vcell;
 161
 162   if (name_hint == SCM_UNDEFINED)
 163     name_hint = anonymous_variable_sym;
 164
 165   SCM_NEWCELL (vcell);
 166   SCM_DEFER_INTS;
 167   SCM_SETCAR (vcell, name_hint);
 168   SCM_SETCDR (vcell, SCM_UNDEFINED);
 169   SCM_ALLOW_INTS;
 170   return make_vcell_variable (vcell);
 171 }
 172
 173
 174 SCM_PROC(s_variable_p, "variable?", 1, 0, 0, scm_variable_p);
 175
 176 SCM
 177 scm_variable_p (obj)
 178      SCM obj;
 179 {
 180   return ( (SCM_NIMP(obj) && SCM_VARIABLEP (obj))
 181           ? SCM_BOOL_T
 182           : SCM_BOOL_F);
 183 }
 184
 185
 186 SCM_PROC(s_variable_ref, "variable-ref", 1, 0, 0, scm_variable_ref);
 187
 188 SCM
 189 scm_variable_ref (var)
 190      SCM var;
 191 {
 192   SCM_ASSERT (SCM_NIMP(var) && SCM_VARIABLEP(var), var, SCM_ARG1, s_variable_ref);
 193   return SCM_CDR (SCM_CDR (var));
 194 }
 195
 196
 197
 198 SCM_PROC(s_variable_set_x, "variable-set!", 2, 0, 0, scm_variable_set_x);
 199
 200 SCM
 201 scm_variable_set_x (var, val)
 202      SCM var;
 203      SCM val;
 204 {
 205   SCM_ASSERT (SCM_NIMP(var) && SCM_VARIABLEP (var), var, SCM_ARG1, s_variable_set_x);
 206   SCM_SETCDR (SCM_CDR (var), val);
 207   return SCM_UNSPECIFIED;
 208 }
 209
 210
 211 SCM_PROC(s_builtin_variable, "builtin-variable", 1, 0, 0, scm_builtin_variable);
 212
 213 SCM
 214 scm_builtin_variable (name)
 215      SCM name;
 216 {
 217   SCM vcell;
 218   SCM var_slot;
 219
 220   SCM_ASSERT (SCM_NIMP (name) && SCM_SYMBOLP (name), name, SCM_ARG1, s_builtin_variable);
 221   vcell = scm_sym2vcell (name, SCM_BOOL_F, SCM_BOOL_T);
 222   if (vcell == SCM_BOOL_F)
 223     return SCM_BOOL_F;
 224
 225   scm_intern_symbol (scm_symhash_vars, name);
 226   var_slot = scm_sym2ovcell (name, scm_symhash_vars);
 227
 228   SCM_DEFER_INTS;
 229   if (   SCM_IMP (SCM_CDR (var_slot))
 230       || (SCM_VARVCELL (var_slot) != vcell))
 231     SCM_SETCDR (var_slot, make_vcell_variable (vcell));
 232   SCM_ALLOW_INTS;
 233
 234   return SCM_CDR (var_slot);
 235 }
 236
 237
 238 SCM_PROC(s_variable_bound_p, "variable-bound?", 1, 0, 0, scm_variable_bound_p);
 239
 240 SCM
 241 scm_variable_bound_p (var)
 242      SCM var;
 243 {
 244   SCM_ASSERT (SCM_NIMP(var) && SCM_VARIABLEP (var), var, SCM_ARG1, s_variable_bound_p);
 245   return (SCM_UNBNDP (SCM_CDR (SCM_VARVCELL (var)))
 246           ? SCM_BOOL_F
 247           : SCM_BOOL_T);
 248 }
 249
 250
 251
 252
 253 void
 254 scm_init_variable ()
 255 {
 256   scm_tc16_variable = scm_newsmob (&variable_smob);
 257   anonymous_variable_sym = SCM_CAR (scm_sysintern ("anonymous-variable", SCM_UNDEFINED));
 258 #include "variable.x"
 259 }
 260