libguile/variable.c

   1 /* Copyright (C) 1995,1996,1997,1998,2000,2001, 2006 Free Software Foundation, Inc.
   2  *
   3  * This library is free software; you can redistribute it and/or
   4  * modify it under the terms of the GNU Lesser General Public
   5  * License as published by the Free Software Foundation; either
   6  * version 2.1 of the License, or (at your option) any later version.
   7  *
   8  * This library 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 GNU
  11  * Lesser General Public License for more details.
  12  *
  13  * You should have received a copy of the GNU Lesser General Public
  14  * License along with this library; if not, write to the Free Software
  15  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  16  */
  17
  18
  19 \f
  20
  21 #include "libguile/_scm.h"
  22 #include "libguile/eq.h"
  23 #include "libguile/ports.h"
  24 #include "libguile/root.h"
  25 #include "libguile/smob.h"
  26 #include "libguile/deprecation.h"
  27
  28 #include "libguile/validate.h"
  29 #include "libguile/variable.h"
  30 \f
  31
  32 void
  33 scm_i_variable_print (SCM exp, SCM port, scm_print_state *pstate)
  34 {
  35   scm_puts ("#<variable ", port);
  36   scm_uintprint (SCM_UNPACK (exp), 16, port);
  37   scm_puts (" value: ", port);
  38   scm_iprin1 (SCM_VARIABLE_REF (exp), port, pstate);
  39   scm_putc('>', port);
  40 }
  41
  42 \f
  43
  44 static SCM
  45 make_variable (SCM init)
  46 {
  47   return scm_cell (scm_tc7_variable, SCM_UNPACK (init));
  48 }
  49
  50 SCM_DEFINE (scm_make_variable, "make-variable", 1, 0, 0,
  51             (SCM init),
  52             "Return a variable initialized to value @var{init}.")
  53 #define FUNC_NAME s_scm_make_variable
  54 {
  55   return make_variable (init);
  56 }
  57 #undef FUNC_NAME
  58
  59
  60 SCM_DEFINE (scm_make_undefined_variable, "make-undefined-variable", 0, 0, 0,
  61             (),
  62             "Return a variable that is initially unbound.")
  63 #define FUNC_NAME s_scm_make_undefined_variable
  64 {
  65   return make_variable (SCM_UNDEFINED);
  66 }
  67 #undef FUNC_NAME
  68
  69
  70 SCM_DEFINE (scm_variable_p, "variable?", 1, 0, 0,
  71             (SCM obj),
  72             "Return @code{#t} iff @var{obj} is a variable object, else\n"
  73             "return @code{#f}.")
  74 #define FUNC_NAME s_scm_variable_p
  75 {
  76   return scm_from_bool (SCM_VARIABLEP (obj));
  77 }
  78 #undef FUNC_NAME
  79
  80
  81 SCM_DEFINE (scm_variable_ref, "variable-ref", 1, 0, 0,
  82             (SCM var),
  83             "Dereference @var{var} and return its value.\n"
  84             "@var{var} must be a variable object; see @code{make-variable}\n"
  85             "and @code{make-undefined-variable}.")
  86 #define FUNC_NAME s_scm_variable_ref
  87 {
  88   SCM val;
  89   SCM_VALIDATE_VARIABLE (1, var);
  90   val = SCM_VARIABLE_REF (var);
  91   if (val == SCM_UNDEFINED)
  92     SCM_MISC_ERROR ("variable is unbound: ~S", scm_list_1 (var));
  93   return val;
  94 }
  95 #undef FUNC_NAME
  96
  97 SCM_DEFINE (scm_variable_set_x, "variable-set!", 2, 0, 0,
  98             (SCM var, SCM val),
  99             "Set the value of the variable @var{var} to @var{val}.\n"
 100             "@var{var} must be a variable object, @var{val} can be any\n"
 101             "value. Return an unspecified value.")
 102 #define FUNC_NAME s_scm_variable_set_x
 103 {
 104   SCM_VALIDATE_VARIABLE (1, var);
 105   SCM_VARIABLE_SET (var, val);
 106   return SCM_UNSPECIFIED;
 107 }
 108 #undef FUNC_NAME
 109
 110 SCM_DEFINE (scm_variable_bound_p, "variable-bound?", 1, 0, 0,
 111             (SCM var),
 112             "Return @code{#t} iff @var{var} is bound to a value.\n"
 113             "Throws an error if @var{var} is not a variable object.")
 114 #define FUNC_NAME s_scm_variable_bound_p
 115 {
 116   SCM_VALIDATE_VARIABLE (1, var);
 117   return scm_from_bool (SCM_VARIABLE_REF (var) != SCM_UNDEFINED);
 118 }
 119 #undef FUNC_NAME
 120
 121
 122 void
 123 scm_init_variable ()
 124 {
 125 #include "libguile/variable.x"
 126 }
 127
 128 /*
 129   Local Variables:
 130   c-file-style: "gnu"
 131   End:
 132 */