libguile/variable.c

   1 /* Copyright (C) 1995,1996,1997,1998,2000,2001, 2006, 2008, 2011 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 License
   5  * as published by the Free Software Foundation; either version 3 of
   6  * the License, or (at your option) any later version.
   7  *
   8  * This library is distributed in the hope that it will be useful, but
   9  * 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
  16  * 02110-1301 USA
  17  */
  18
  19
  20 \f
  21 #ifdef HAVE_CONFIG_H
  22 # include <config.h>
  23 #endif
  24
  25 #include "libguile/_scm.h"
  26 #include "libguile/eq.h"
  27 #include "libguile/ports.h"
  28 #include "libguile/root.h"
  29 #include "libguile/smob.h"
  30 #include "libguile/deprecation.h"
  31
  32 #include "libguile/validate.h"
  33 #include "libguile/variable.h"
  34 \f
  35
  36 void
  37 scm_i_variable_print (SCM exp, SCM port, scm_print_state *pstate)
  38 {
  39   scm_puts_unlocked ("#<variable ", port);
  40   scm_uintprint (SCM_UNPACK (exp), 16, port);
  41   scm_puts_unlocked (" value: ", port);
  42   scm_iprin1 (SCM_VARIABLE_REF (exp), port, pstate);
  43   scm_putc_unlocked('>', port);
  44 }
  45
  46 \f
  47
  48 static SCM
  49 make_variable (SCM init)
  50 {
  51   return scm_cell (scm_tc7_variable, SCM_UNPACK (init));
  52 }
  53
  54 SCM_DEFINE (scm_make_variable, "make-variable", 1, 0, 0,
  55             (SCM init),
  56             "Return a variable initialized to value @var{init}.")
  57 #define FUNC_NAME s_scm_make_variable
  58 {
  59   return make_variable (init);
  60 }
  61 #undef FUNC_NAME
  62
  63
  64 SCM_DEFINE (scm_make_undefined_variable, "make-undefined-variable", 0, 0, 0,
  65             (),
  66             "Return a variable that is initially unbound.")
  67 #define FUNC_NAME s_scm_make_undefined_variable
  68 {
  69   return make_variable (SCM_UNDEFINED);
  70 }
  71 #undef FUNC_NAME
  72
  73
  74 SCM_DEFINE (scm_variable_p, "variable?", 1, 0, 0,
  75             (SCM obj),
  76             "Return @code{#t} iff @var{obj} is a variable object, else\n"
  77             "return @code{#f}.")
  78 #define FUNC_NAME s_scm_variable_p
  79 {
  80   return scm_from_bool (SCM_VARIABLEP (obj));
  81 }
  82 #undef FUNC_NAME
  83
  84
  85 SCM_DEFINE (scm_variable_ref, "variable-ref", 1, 0, 0,
  86             (SCM var),
  87             "Dereference @var{var} and return its value.\n"
  88             "@var{var} must be a variable object; see @code{make-variable}\n"
  89             "and @code{make-undefined-variable}.")
  90 #define FUNC_NAME s_scm_variable_ref
  91 {
  92   SCM val;
  93   SCM_VALIDATE_VARIABLE (1, var);
  94   val = SCM_VARIABLE_REF (var);
  95   if (scm_is_eq (val, SCM_UNDEFINED))
  96     SCM_MISC_ERROR ("variable is unbound: ~S", scm_list_1 (var));
  97   return val;
  98 }
  99 #undef FUNC_NAME
 100
 101 SCM_DEFINE (scm_variable_set_x, "variable-set!", 2, 0, 0,
 102             (SCM var, SCM val),
 103             "Set the value of the variable @var{var} to @var{val}.\n"
 104             "@var{var} must be a variable object, @var{val} can be any\n"
 105             "value. Return an unspecified value.")
 106 #define FUNC_NAME s_scm_variable_set_x
 107 {
 108   SCM_VALIDATE_VARIABLE (1, var);
 109   SCM_VARIABLE_SET (var, val);
 110   return SCM_UNSPECIFIED;
 111 }
 112 #undef FUNC_NAME
 113
 114 SCM_DEFINE (scm_variable_unset_x, "variable-unset!", 1, 0, 0,
 115             (SCM var),
 116             "Ensure that @var{var} is not bound to a value.\n"
 117             "@var{var} must be a variable object.")
 118 #define FUNC_NAME s_scm_variable_unset_x
 119 {
 120   SCM_VALIDATE_VARIABLE (1, var);
 121   SCM_VARIABLE_SET (var, SCM_UNDEFINED);
 122   return SCM_UNSPECIFIED;
 123 }
 124 #undef FUNC_NAME
 125
 126 SCM_DEFINE (scm_variable_bound_p, "variable-bound?", 1, 0, 0,
 127             (SCM var),
 128             "Return @code{#t} iff @var{var} is bound to a value.\n"
 129             "Throws an error if @var{var} is not a variable object.")
 130 #define FUNC_NAME s_scm_variable_bound_p
 131 {
 132   SCM_VALIDATE_VARIABLE (1, var);
 133   return scm_from_bool (!scm_is_eq (SCM_VARIABLE_REF (var), SCM_UNDEFINED));
 134 }
 135 #undef FUNC_NAME
 136
 137
 138 void
 139 scm_init_variable ()
 140 {
 141 #include "libguile/variable.x"
 142 }
 143
 144 /*
 145   Local Variables:
 146   c-file-style: "gnu"
 147   End:
 148 */