libguile/variable.c

   1 /*      Copyright (C) 1995, 1996, 1997, 1998 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 int prin_var SCM_P ((SCM exp, SCM port, scm_print_state *pstate));
  53
  54 static int
  55 prin_var (exp, port, pstate)
  56      SCM exp;
  57      SCM port;
  58      scm_print_state *pstate;
  59 {
  60   scm_puts ("#<variable ", port);
  61   scm_intprint(exp, 16, port);
  62   {
  63     SCM val_cell;
  64     val_cell = SCM_CDR(exp);
  65     if (SCM_CAR (val_cell) != SCM_UNDEFINED)
  66       {
  67         scm_puts (" name: ", port);
  68         scm_iprin1 (SCM_CAR (val_cell), port, pstate);
  69       }
  70     scm_puts (" binding: ", port);
  71     scm_iprin1 (SCM_CDR (val_cell), port, pstate);
  72   }
  73   scm_putc('>', port);
  74   return 1;
  75 }
  76
  77
  78 static SCM scm_markvar SCM_P ((SCM ptr));
  79
  80 static SCM
  81 scm_markvar (ptr)
  82      SCM ptr;
  83 {
  84   return SCM_CDR (ptr);
  85 }
  86
  87 static SCM var_equal SCM_P ((SCM var1, SCM var2));
  88
  89 static SCM
  90 var_equal (var1, var2)
  91      SCM var1;
  92      SCM var2;
  93 {
  94   return scm_equal_p (SCM_CDR (var1), SCM_CDR (var2));
  95 }
  96
  97 int scm_tc16_variable;
  98 \f
  99
 100 static SCM anonymous_variable_sym;
 101
 102
 103 static SCM make_vcell_variable SCM_P ((SCM vcell));
 104
 105 static SCM
 106 make_vcell_variable (vcell)
 107      SCM vcell;
 108 {
 109   SCM_RETURN_NEWSMOB (scm_tc16_variable, vcell);
 110 }
 111
 112 SCM_PROC(s_make_variable, "make-variable", 1, 1, 0, scm_make_variable);
 113
 114 SCM
 115 scm_make_variable (init, name_hint)
 116      SCM init;
 117      SCM name_hint;
 118 {
 119   SCM val_cell;
 120
 121   if (name_hint == SCM_UNDEFINED)
 122     name_hint = anonymous_variable_sym;
 123
 124   SCM_NEWCELL(val_cell);
 125   SCM_DEFER_INTS;
 126   SCM_SETCAR (val_cell, name_hint);
 127   SCM_SETCDR (val_cell, init);
 128   SCM_ALLOW_INTS;
 129   return make_vcell_variable (val_cell);
 130 }
 131
 132
 133 SCM_PROC(s_make_undefined_variable, "make-undefined-variable", 0, 1, 0, scm_make_undefined_variable);
 134
 135 SCM
 136 scm_make_undefined_variable (name_hint)
 137      SCM name_hint;
 138 {
 139   SCM vcell;
 140
 141   if (name_hint == SCM_UNDEFINED)
 142     name_hint = anonymous_variable_sym;
 143
 144   SCM_NEWCELL (vcell);
 145   SCM_DEFER_INTS;
 146   SCM_SETCAR (vcell, name_hint);
 147   SCM_SETCDR (vcell, SCM_UNDEFINED);
 148   SCM_ALLOW_INTS;
 149   return make_vcell_variable (vcell);
 150 }
 151
 152
 153 SCM_PROC(s_variable_p, "variable?", 1, 0, 0, scm_variable_p);
 154
 155 SCM
 156 scm_variable_p (obj)
 157      SCM obj;
 158 {
 159   return ( (SCM_NIMP(obj) && SCM_VARIABLEP (obj))
 160           ? SCM_BOOL_T
 161           : SCM_BOOL_F);
 162 }
 163
 164
 165 SCM_PROC(s_variable_ref, "variable-ref", 1, 0, 0, scm_variable_ref);
 166
 167 SCM
 168 scm_variable_ref (var)
 169      SCM var;
 170 {
 171   SCM_ASSERT (SCM_NIMP(var) && SCM_VARIABLEP(var), var, SCM_ARG1, s_variable_ref);
 172   return SCM_CDR (SCM_CDR (var));
 173 }
 174
 175
 176
 177 SCM_PROC(s_variable_set_x, "variable-set!", 2, 0, 0, scm_variable_set_x);
 178
 179 SCM
 180 scm_variable_set_x (var, val)
 181      SCM var;
 182      SCM val;
 183 {
 184   SCM_ASSERT (SCM_NIMP(var) && SCM_VARIABLEP (var), var, SCM_ARG1, s_variable_set_x);
 185   SCM_SETCDR (SCM_CDR (var), val);
 186   return SCM_UNSPECIFIED;
 187 }
 188
 189
 190 SCM_PROC(s_builtin_variable, "builtin-variable", 1, 0, 0, scm_builtin_variable);
 191
 192 SCM
 193 scm_builtin_variable (name)
 194      SCM name;
 195 {
 196   SCM vcell;
 197   SCM var_slot;
 198
 199   SCM_ASSERT (SCM_NIMP (name) && SCM_SYMBOLP (name), name, SCM_ARG1, s_builtin_variable);
 200   vcell = scm_sym2vcell (name, SCM_BOOL_F, SCM_BOOL_T);
 201   if (vcell == SCM_BOOL_F)
 202     return SCM_BOOL_F;
 203
 204   scm_intern_symbol (scm_symhash_vars, name);
 205   var_slot = scm_sym2ovcell (name, scm_symhash_vars);
 206
 207   SCM_DEFER_INTS;
 208   if (   SCM_IMP (SCM_CDR (var_slot))
 209       || (SCM_VARVCELL (var_slot) != vcell))
 210     SCM_SETCDR (var_slot, make_vcell_variable (vcell));
 211   SCM_ALLOW_INTS;
 212
 213   return SCM_CDR (var_slot);
 214 }
 215
 216
 217 SCM_PROC(s_variable_bound_p, "variable-bound?", 1, 0, 0, scm_variable_bound_p);
 218
 219 SCM
 220 scm_variable_bound_p (var)
 221      SCM var;
 222 {
 223   SCM_ASSERT (SCM_NIMP(var) && SCM_VARIABLEP (var), var, SCM_ARG1, s_variable_bound_p);
 224   return (SCM_UNBNDP (SCM_CDR (SCM_VARVCELL (var)))
 225           ? SCM_BOOL_F
 226           : SCM_BOOL_T);
 227 }
 228
 229
 230
 231
 232 void
 233 scm_init_variable ()
 234 {
 235   scm_tc16_variable = scm_make_smob_type_mfpe ("variable", 0,
 236                                               scm_markvar, NULL, prin_var, var_equal);
 237   anonymous_variable_sym = SCM_CAR (scm_sysintern ("anonymous-variable", SCM_UNDEFINED));
 238 #include "variable.x"
 239 }
 240