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d38b431ace
* libguile/boolean.h (scm_is_false): Recognize nil as false, by default. (scm_is_bool): Recognize nil as a boolean. * libguile/boolean.c (scm_not, scm_boolean, scm_to_bool, scm_is_bool): Adapt to treat nil as false. * libguile/vm-i-system.c (br-if, br-if-not): Just use scm_is_false instead of specifically mentioning nil.
110 lines
2.9 KiB
C
110 lines
2.9 KiB
C
/* Copyright (C) 1995, 1996, 2000, 2001, 2006, 2008, 2009, 2010 Free Software Foundation, Inc.
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*
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* This library is free software; you can redistribute it and/or
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* modify it under the terms of the GNU Lesser General Public License
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* as published by the Free Software Foundation; either version 3 of
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* the License, or (at your option) any later version.
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*
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* This library is distributed in the hope that it will be useful, but
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* WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* Lesser General Public License for more details.
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*
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* You should have received a copy of the GNU Lesser General Public
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* License along with this library; if not, write to the Free Software
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* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
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* 02110-1301 USA
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*/
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#ifdef HAVE_CONFIG_H
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# include <config.h>
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#endif
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#include "libguile/_scm.h"
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#include "libguile/validate.h"
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#include "libguile/boolean.h"
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#include "libguile/lang.h"
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#include "libguile/tags.h"
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#include "verify.h"
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/*
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* These compile-time tests verify the properties needed for the
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* efficient test macros defined in boolean.h, which are defined in
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* terms of the SCM_MATCHES_BITS_IN_COMMON macro.
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*
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* See the comments preceeding the definitions of SCM_BOOL_F and
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* SCM_MATCHES_BITS_IN_COMMON in tags.h for more information.
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*/
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verify (SCM_VALUES_DIFFER_IN_EXACTLY_ONE_BIT_POSITION \
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(SCM_BOOL_F, SCM_BOOL_T));
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verify (SCM_VALUES_DIFFER_IN_EXACTLY_ONE_BIT_POSITION \
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(SCM_ELISP_NIL, SCM_BOOL_F));
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verify (SCM_VALUES_DIFFER_IN_EXACTLY_ONE_BIT_POSITION \
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(SCM_ELISP_NIL, SCM_EOL));
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verify (SCM_VALUES_DIFFER_IN_EXACTLY_TWO_BIT_POSITIONS \
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(SCM_ELISP_NIL, SCM_BOOL_F, SCM_BOOL_T, \
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SCM_XXX_ANOTHER_BOOLEAN_DONT_USE_0));
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verify (SCM_VALUES_DIFFER_IN_EXACTLY_TWO_BIT_POSITIONS \
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(SCM_ELISP_NIL, SCM_BOOL_F, SCM_EOL, \
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SCM_XXX_ANOTHER_LISP_FALSE_DONT_USE));
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SCM_DEFINE (scm_not, "not", 1, 0, 0,
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(SCM x),
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"Return @code{#t} iff @var{x} is false, else return @code{#f}.")
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#define FUNC_NAME s_scm_not
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{
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return scm_from_bool (scm_is_false (x));
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}
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#undef FUNC_NAME
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SCM_DEFINE (scm_boolean_p, "boolean?", 1, 0, 0,
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(SCM obj),
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"Return @code{#t} iff @var{obj} is @code{#t} or false.")
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#define FUNC_NAME s_scm_boolean_p
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{
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return scm_from_bool (scm_is_bool (obj));
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}
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#undef FUNC_NAME
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int
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scm_to_bool (SCM x)
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{
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if (scm_is_false (x))
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return 0;
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else if (scm_is_eq (x, SCM_BOOL_T))
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return 1;
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else
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scm_wrong_type_arg (NULL, 0, x);
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}
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/* We keep this primitive as a function in addition to the same-named macro
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because some applications (e.g., GNU LilyPond 2.13.9) expect it to be a
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function. */
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#undef scm_is_bool
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int
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scm_is_bool (SCM obj)
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{
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/* This must match the macro definition of `scm_is_bool ()'. */
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return scm_is_bool_or_nil (obj);
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}
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void
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scm_init_boolean ()
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{
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#include "libguile/boolean.x"
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}
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/*
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Local Variables:
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c-file-style: "gnu"
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End:
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*/
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