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
  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 \f
  46
  47 #include <stdio.h>
  48 #include "_scm.h"
  49 #include "eq.h"
  50 #include "genio.h"
  51 #include "smob.h"
  52
  53 #include "scm_validate.h"
  54 #include "variable.h"
  55 \f
  56
  57 static int
  58 prin_var (SCM exp,SCM port,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
  79 scm_markvar (SCM ptr)
  80 {
  81   return SCM_CDR (ptr);
  82 }
  83
  84 static SCM
  85 var_equal (SCM var1, SCM var2)
  86 {
  87   return scm_equal_p (SCM_CDR (var1), SCM_CDR (var2));
  88 }
  89
  90 int scm_tc16_variable;
  91 \f
  92
  93 static SCM anonymous_variable_sym;
  94
  95
  96 static SCM
  97 make_vcell_variable (SCM vcell)
  98 {
  99   SCM_RETURN_NEWSMOB (scm_tc16_variable, vcell);
 100 }
 101
 102 GUILE_PROC(scm_make_variable, "make-variable", 1, 1, 0,
 103            (SCM init, SCM name_hint),
 104 "")
 105 #define FUNC_NAME s_scm_make_variable
 106 {
 107   SCM val_cell;
 108
 109   if (name_hint == SCM_UNDEFINED)
 110     name_hint = anonymous_variable_sym;
 111
 112   SCM_NEWCELL(val_cell);
 113   SCM_DEFER_INTS;
 114   SCM_SETCAR (val_cell, name_hint);
 115   SCM_SETCDR (val_cell, init);
 116   SCM_ALLOW_INTS;
 117   return make_vcell_variable (val_cell);
 118 }
 119 #undef FUNC_NAME
 120
 121
 122 GUILE_PROC(scm_make_undefined_variable, "make-undefined-variable", 0, 1, 0,
 123            (SCM name_hint),
 124 "")
 125 #define FUNC_NAME s_scm_make_undefined_variable
 126 {
 127   SCM vcell;
 128
 129   if (name_hint == SCM_UNDEFINED)
 130     name_hint = anonymous_variable_sym;
 131
 132   SCM_NEWCELL (vcell);
 133   SCM_DEFER_INTS;
 134   SCM_SETCAR (vcell, name_hint);
 135   SCM_SETCDR (vcell, SCM_UNDEFINED);
 136   SCM_ALLOW_INTS;
 137   return make_vcell_variable (vcell);
 138 }
 139 #undef FUNC_NAME
 140
 141
 142 GUILE_PROC(scm_variable_p, "variable?", 1, 0, 0,
 143            (SCM obj),
 144 "")
 145 #define FUNC_NAME s_scm_variable_p
 146 {
 147   return SCM_BOOL(SCM_NIMP(obj) && SCM_VARIABLEP (obj));
 148 }
 149 #undef FUNC_NAME
 150
 151
 152 GUILE_PROC(scm_variable_ref, "variable-ref", 1, 0, 0,
 153            (SCM var),
 154 "")
 155 #define FUNC_NAME s_scm_variable_ref
 156 {
 157   SCM_VALIDATE_VARIABLE(1,var);
 158   return SCM_CDR (SCM_CDR (var));
 159 }
 160 #undef FUNC_NAME
 161
 162
 163
 164 GUILE_PROC(scm_variable_set_x, "variable-set!", 2, 0, 0,
 165            (SCM var, SCM val),
 166 "")
 167 #define FUNC_NAME s_scm_variable_set_x
 168 {
 169   SCM_VALIDATE_VARIABLE(1,var);
 170   SCM_SETCDR (SCM_CDR (var), val);
 171   return SCM_UNSPECIFIED;
 172 }
 173 #undef FUNC_NAME
 174
 175
 176 GUILE_PROC(scm_builtin_variable, "builtin-variable", 1, 0, 0,
 177            (SCM name),
 178 "")
 179 #define FUNC_NAME s_scm_builtin_variable
 180 {
 181   SCM vcell;
 182   SCM var_slot;
 183
 184   SCM_VALIDATE_SYMBOL(1,name);
 185   vcell = scm_sym2vcell (name, SCM_BOOL_F, SCM_BOOL_T);
 186   if (vcell == SCM_BOOL_F)
 187     return SCM_BOOL_F;
 188
 189   scm_intern_symbol (scm_symhash_vars, name);
 190   var_slot = scm_sym2ovcell (name, scm_symhash_vars);
 191
 192   SCM_DEFER_INTS;
 193   if (   SCM_IMP (SCM_CDR (var_slot))
 194       || (SCM_VARVCELL (var_slot) != vcell))
 195     SCM_SETCDR (var_slot, make_vcell_variable (vcell));
 196   SCM_ALLOW_INTS;
 197
 198   return SCM_CDR (var_slot);
 199 }
 200 #undef FUNC_NAME
 201
 202
 203 GUILE_PROC(scm_variable_bound_p, "variable-bound?", 1, 0, 0,
 204            (SCM var),
 205 "")
 206 #define FUNC_NAME s_scm_variable_bound_p
 207 {
 208   SCM_VALIDATE_VARIABLE(1,var);
 209   return SCM_NEGATE_BOOL(SCM_UNBNDP (SCM_CDR (SCM_VARVCELL (var))));
 210 }
 211 #undef FUNC_NAME
 212
 213
 214
 215
 216 void
 217 scm_init_variable ()
 218 {
 219   scm_tc16_variable = scm_make_smob_type_mfpe ("variable", 0,
 220                                               scm_markvar, NULL, prin_var, var_equal);
 221   anonymous_variable_sym = SCM_CAR (scm_sysintern ("anonymous-variable", SCM_UNDEFINED));
 222 #include "variable.x"
 223 }
 224