libguile/variable.c

   1 /* Copyright (C) 1995,1996,1997,1998,2000,2001 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
  43 \f
  44
  45 #include "libguile/_scm.h"
  46 #include "libguile/eq.h"
  47 #include "libguile/ports.h"
  48 #include "libguile/root.h"
  49 #include "libguile/smob.h"
  50 #include "libguile/deprecation.h"
  51
  52 #include "libguile/validate.h"
  53 #include "libguile/variable.h"
  54 \f
  55
  56 void
  57 scm_i_variable_print (SCM exp, SCM port, scm_print_state *pstate)
  58 {
  59   scm_puts ("#<variable ", port);
  60   scm_intprint (SCM_UNPACK (exp), 16, port);
  61   scm_puts (" value: ", port);
  62   scm_iprin1 (SCM_VARIABLE_REF (exp), port, pstate);
  63   scm_putc('>', port);
  64 }
  65
  66 \f
  67
  68 #if SCM_ENABLE_VCELLS
  69 SCM_SYMBOL (sym_huh, "???");
  70 #endif
  71
  72 static SCM
  73 make_variable (SCM init)
  74 {
  75 #if !SCM_ENABLE_VCELLS
  76   {
  77     SCM z;
  78     SCM_NEWCELL (z);
  79     SCM_SET_CELL_WORD_1 (z, SCM_UNPACK (init));
  80     SCM_SET_CELL_TYPE (z, scm_tc7_variable);
  81     scm_remember_upto_here_1 (init);
  82     return z;
  83   }
  84 #else
  85   {
  86     SCM z;
  87     SCM cell = scm_cons (sym_huh, init);
  88     SCM_NEWCELL (z);
  89     SCM_SET_CELL_WORD_1 (z, SCM_UNPACK (cell));
  90     SCM_SET_CELL_TYPE (z, scm_tc7_variable);
  91     scm_remember_upto_here_1 (cell);
  92     return z;
  93   }
  94 #endif
  95 }
  96
  97 SCM_DEFINE (scm_make_variable, "make-variable", 1, 0, 0,
  98             (SCM init),
  99             "Return a variable initialized to value @var{init}.\n")
 100 #define FUNC_NAME s_scm_make_variable
 101 {
 102   return make_variable (init);
 103 }
 104 #undef FUNC_NAME
 105
 106
 107 SCM_DEFINE (scm_make_undefined_variable, "make-undefined-variable", 0, 0, 0,
 108             (),
 109             "Return a variable that is initially unbound.\n")
 110 #define FUNC_NAME s_scm_make_undefined_variable
 111 {
 112   return make_variable (SCM_UNDEFINED);
 113 }
 114 #undef FUNC_NAME
 115
 116
 117 SCM_DEFINE (scm_variable_p, "variable?", 1, 0, 0,
 118             (SCM obj),
 119             "Return @code{#t} iff @var{obj} is a variable object, else\n"
 120             "return @code{#f}\n")
 121 #define FUNC_NAME s_scm_variable_p
 122 {
 123   return SCM_BOOL (SCM_VARIABLEP (obj));
 124 }
 125 #undef FUNC_NAME
 126
 127
 128 SCM_DEFINE (scm_variable_ref, "variable-ref", 1, 0, 0,
 129             (SCM var),
 130             "Dereference @var{var} and return its value.\n"
 131             "@var{var} must be a variable object; see @code{make-variable}\n"
 132             "and @code{make-undefined-variable}.")
 133 #define FUNC_NAME s_scm_variable_ref
 134 {
 135   SCM val;
 136   SCM_VALIDATE_VARIABLE (1, var);
 137   val = SCM_VARIABLE_REF (var);
 138   if (val == SCM_UNDEFINED)
 139     SCM_MISC_ERROR ("variable is unbound: ~S", scm_list_1 (var));
 140   return val;
 141 }
 142 #undef FUNC_NAME
 143
 144 SCM_DEFINE (scm_variable_set_x, "variable-set!", 2, 0, 0,
 145             (SCM var, SCM val),
 146             "Set the value of the variable @var{var} to @var{val}.\n"
 147             "@var{var} must be a variable object, @var{val} can be any\n"
 148             "value. Return an unspecified value.\n")
 149 #define FUNC_NAME s_scm_variable_set_x
 150 {
 151   SCM_VALIDATE_VARIABLE (1, var);
 152   SCM_VARIABLE_SET (var, val);
 153   return SCM_UNSPECIFIED;
 154 }
 155 #undef FUNC_NAME
 156
 157 SCM_DEFINE (scm_variable_bound_p, "variable-bound?", 1, 0, 0,
 158             (SCM var),
 159             "Return @code{#t} iff @var{var} is bound to a value.\n"
 160             "Throws an error if @var{var} is not a variable object.\n")
 161 #define FUNC_NAME s_scm_variable_bound_p
 162 {
 163   SCM_VALIDATE_VARIABLE (1, var);
 164   return SCM_BOOL (SCM_VARIABLE_REF (var) != SCM_UNDEFINED);
 165 }
 166 #undef FUNC_NAME
 167
 168 SCM_DEFINE (scm_variable_set_name_hint, "variable-set-name-hint!", 2, 0, 0,
 169             (SCM var, SCM hint),
 170             "Do not use this function.")
 171 #define FUNC_NAME s_scm_variable_set_name_hint
 172 {
 173   SCM_VALIDATE_VARIABLE (1, var);
 174   SCM_VALIDATE_SYMBOL (2, hint);
 175 #if SCM_ENABLE_VCELLS
 176   SCM_SETCAR (SCM_SMOB_DATA (var), hint);
 177 #endif
 178   return SCM_UNSPECIFIED;
 179 }
 180 #undef FUNC_NAME
 181
 182 #if SCM_ENABLE_VCELLS
 183
 184 SCM_DEFINE (scm_builtin_variable, "builtin-variable", 1, 0, 0,
 185             (SCM name),
 186             "Return the built-in variable with the name @var{name}.\n"
 187             "@var{name} must be a symbol (not a string).\n"
 188             "Then use @code{variable-ref} to access its value.\n")
 189 #define FUNC_NAME s_scm_builtin_variable
 190 {
 191   SCM_VALIDATE_SYMBOL (1,name);
 192   scm_c_issue_deprecation_warning ("`builtin-variable' is deprecated. "
 193                                    "Use module system operations instead.");
 194   return scm_sym2var (name, SCM_BOOL_F, SCM_BOOL_T);
 195 }
 196 #undef FUNC_NAME
 197
 198 #endif /* SCM_ENABLE_VCELLS */
 199
 200 void
 201 scm_init_variable ()
 202 {
 203 #ifndef SCM_MAGIC_SNARFER
 204 #include "libguile/variable.x"
 205 #endif
 206 }
 207
 208 /*
 209   Local Variables:
 210   c-file-style: "gnu"
 211   End:
 212 */