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
  66 SCM_DEFINE (scm_boolean_p, "boolean?", 1, 0, 0,
  67            (SCM obj),
  68             "Return @code{#t} iff @var{obj} is @code{#t} or false.")
  69 #define FUNC_NAME s_scm_boolean_p
  70 {
  71   return scm_from_bool (scm_is_bool (obj));
  72 }
  73 #undef FUNC_NAME
  74
  75 int
  76 scm_to_bool (SCM x)
  77 {
  78   if (scm_is_false (x))
  79     return 0;
  80   else if (scm_is_eq (x, SCM_BOOL_T))
  81     return 1;
  82   else
  83     scm_wrong_type_arg (NULL, 0, x);
  84 }
  85
  86 /* We keep this primitive as a function in addition to the same-named macro
  87    because some applications (e.g., GNU LilyPond 2.13.9) expect it to be a
  88    function.  */
  89 #undef scm_is_bool
  90 int
  91 scm_is_bool (SCM obj)
  92 {
  93   /* This must match the macro definition of `scm_is_bool ()'.  */
  94   return scm_is_bool_or_nil (obj);
  95 }
  96
  97 \f
  98 void
  99 scm_init_boolean ()
 100 {
 101 #include "libguile/boolean.x"
 102 }
 103
 104
 105 /*
 106   Local Variables:
 107   c-file-style: "gnu"
 108   End:
 109 */