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 static SCM
  69 make_variable (SCM init)
  70 {
  71   SCM z;
  72   SCM_NEWCELL (z);
  73   SCM_SET_CELL_WORD_1 (z, SCM_UNPACK (init));
  74   SCM_SET_CELL_TYPE (z, scm_tc7_variable);
  75   scm_remember_upto_here_1 (init);
  76   return z;
  77 }
  78
  79 SCM_DEFINE (scm_make_variable, "make-variable", 1, 0, 0,
  80             (SCM init),
  81             "Return a variable initialized to value @var{init}.\n")
  82 #define FUNC_NAME s_scm_make_variable
  83 {
  84   return make_variable (init);
  85 }
  86 #undef FUNC_NAME
  87
  88
  89 SCM_DEFINE (scm_make_undefined_variable, "make-undefined-variable", 0, 0, 0,
  90             (),
  91             "Return a variable that is initially unbound.\n")
  92 #define FUNC_NAME s_scm_make_undefined_variable
  93 {
  94   return make_variable (SCM_UNDEFINED);
  95 }
  96 #undef FUNC_NAME
  97
  98
  99 SCM_DEFINE (scm_variable_p, "variable?", 1, 0, 0,
 100             (SCM obj),
 101             "Return @code{#t} iff @var{obj} is a variable object, else\n"
 102             "return @code{#f}\n")
 103 #define FUNC_NAME s_scm_variable_p
 104 {
 105   return SCM_BOOL (SCM_VARIABLEP (obj));
 106 }
 107 #undef FUNC_NAME
 108
 109
 110 SCM_DEFINE (scm_variable_ref, "variable-ref", 1, 0, 0,
 111             (SCM var),
 112             "Dereference @var{var} and return its value.\n"
 113             "@var{var} must be a variable object; see @code{make-variable}\n"
 114             "and @code{make-undefined-variable}.")
 115 #define FUNC_NAME s_scm_variable_ref
 116 {
 117   SCM val;
 118   SCM_VALIDATE_VARIABLE (1, var);
 119   val = SCM_VARIABLE_REF (var);
 120   if (val == SCM_UNDEFINED)
 121     SCM_MISC_ERROR ("variable is unbound: ~S", scm_list_1 (var));
 122   return val;
 123 }
 124 #undef FUNC_NAME
 125
 126 SCM_DEFINE (scm_variable_set_x, "variable-set!", 2, 0, 0,
 127             (SCM var, SCM val),
 128             "Set the value of the variable @var{var} to @var{val}.\n"
 129             "@var{var} must be a variable object, @var{val} can be any\n"
 130             "value. Return an unspecified value.\n")
 131 #define FUNC_NAME s_scm_variable_set_x
 132 {
 133   SCM_VALIDATE_VARIABLE (1, var);
 134   SCM_VARIABLE_SET (var, val);
 135   return SCM_UNSPECIFIED;
 136 }
 137 #undef FUNC_NAME
 138
 139 SCM_DEFINE (scm_variable_bound_p, "variable-bound?", 1, 0, 0,
 140             (SCM var),
 141             "Return @code{#t} iff @var{var} is bound to a value.\n"
 142             "Throws an error if @var{var} is not a variable object.\n")
 143 #define FUNC_NAME s_scm_variable_bound_p
 144 {
 145   SCM_VALIDATE_VARIABLE (1, var);
 146   return SCM_BOOL (SCM_VARIABLE_REF (var) != SCM_UNDEFINED);
 147 }
 148 #undef FUNC_NAME
 149
 150
 151 void
 152 scm_init_variable ()
 153 {
 154 #ifndef SCM_MAGIC_SNARFER
 155 #include "libguile/variable.x"
 156 #endif
 157 }
 158
 159 /*
 160   Local Variables:
 161   c-file-style: "gnu"
 162   End:
 163 */