libguile/boolean.c

   1 /*      Copyright (C) 1995, 1996, 2000, 2001, 2006, 2008, 2009, 2010, 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
  27 #include "libguile/validate.h"
  28 #include "libguile/boolean.h"
  29 #include "libguile/tags.h"
  30
  31 #include "verify.h"
  32
  33 \f
  34
  35 /*
  36  * These compile-time tests verify the properties needed for the
  37  * efficient test macros defined in boolean.h, which are defined in
  38  * terms of the SCM_MATCHES_BITS_IN_COMMON macro.
  39  *
  40  * See the comments preceeding the definitions of SCM_BOOL_F and
  41  * SCM_MATCHES_BITS_IN_COMMON in tags.h for more information.
  42  */
  43 verify (SCM_BITS_DIFFER_IN_EXACTLY_ONE_BIT_POSITION             \
  44         (SCM_BOOL_F_BITS, SCM_BOOL_T_BITS));
  45 verify (SCM_BITS_DIFFER_IN_EXACTLY_ONE_BIT_POSITION     \
  46         (SCM_ELISP_NIL_BITS, SCM_BOOL_F_BITS));
  47 verify (SCM_BITS_DIFFER_IN_EXACTLY_ONE_BIT_POSITION     \
  48         (SCM_ELISP_NIL_BITS, SCM_EOL_BITS));
  49 verify (SCM_BITS_DIFFER_IN_EXACTLY_TWO_BIT_POSITIONS            \
  50         (SCM_ELISP_NIL_BITS, SCM_BOOL_F_BITS, SCM_BOOL_T_BITS,  \
  51          SCM_XXX_ANOTHER_BOOLEAN_DONT_USE_0));
  52 verify (SCM_BITS_DIFFER_IN_EXACTLY_TWO_BIT_POSITIONS            \
  53         (SCM_ELISP_NIL_BITS, SCM_BOOL_F_BITS, SCM_EOL_BITS,     \
  54          SCM_XXX_ANOTHER_LISP_FALSE_DONT_USE));
  55
  56 SCM_DEFINE (scm_not, "not", 1, 0, 0,
  57             (SCM x),
  58             "Return @code{#t} iff @var{x} is false, else return @code{#f}.")
  59 #define FUNC_NAME s_scm_not
  60 {
  61   return scm_from_bool (scm_is_false (x));
  62 }
  63 #undef FUNC_NAME
  64
  65 SCM_DEFINE (scm_nil_p, "nil?", 1, 0, 0,
  66             (SCM x),
  67             "Return @code{#t} iff @var{x} is nil, else return @code{#f}.")
  68 #define FUNC_NAME s_scm_nil_p
  69 {
  70   return scm_from_bool (scm_is_lisp_false (x));
  71 }
  72 #undef FUNC_NAME
  73
  74 SCM_DEFINE (scm_boolean_p, "boolean?", 1, 0, 0,
  75            (SCM obj),
  76             "Return @code{#t} iff @var{obj} is @code{#t} or false.")
  77 #define FUNC_NAME s_scm_boolean_p
  78 {
  79   return scm_from_bool (scm_is_bool (obj));
  80 }
  81 #undef FUNC_NAME
  82
  83 int
  84 scm_to_bool (SCM x)
  85 {
  86   if (scm_is_false (x))
  87     return 0;
  88   else if (scm_is_eq (x, SCM_BOOL_T))
  89     return 1;
  90   else
  91     scm_wrong_type_arg (NULL, 0, x);
  92 }
  93
  94 /* We keep this primitive as a function in addition to the same-named macro
  95    because some applications (e.g., GNU LilyPond 2.13.9) expect it to be a
  96    function.  */
  97 #undef scm_is_bool
  98 int
  99 scm_is_bool (SCM obj)
 100 {
 101   /* This must match the macro definition of `scm_is_bool ()'.  */
 102   return scm_is_bool_or_nil (obj);
 103 }
 104
 105 \f
 106 void
 107 scm_init_boolean ()
 108 {
 109 #include "libguile/boolean.x"
 110 }
 111
 112
 113 /*
 114   Local Variables:
 115   c-file-style: "gnu"
 116   End:
 117 */