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Update to newest recommended license notices from the FSF. Everything stays LGPLv3+ except guile-readline which is GPLv3+.
150 lines
4.8 KiB
C
150 lines
4.8 KiB
C
#ifndef SCM_BOOLEAN_H
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#define SCM_BOOLEAN_H
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/* Copyright 1995-1996,2000,2006,2008-2010,2013,2018
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Free Software Foundation, Inc.
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This file is part of Guile.
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Guile is free software: you can redistribute it and/or modify it
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under the terms of the GNU Lesser General Public License as published
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by the Free Software Foundation, either version 3 of the License, or
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(at your option) any later version.
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Guile is distributed in the hope that it will be useful, but WITHOUT
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ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
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FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public
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License for more details.
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You should have received a copy of the GNU Lesser General Public
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License along with Guile. If not, see
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<https://www.gnu.org/licenses/>. */
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#include "libguile/scm.h"
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/* Boolean Values. Obviously there are #t and #f, but there is also nil to deal
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* with. We choose to treat nil as a false boolean. All options might silently
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* break existing code, but this one seems most responsible.
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*
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*/
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/*
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* Use these macros if it's important (for correctness)
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* that #nil MUST be considered true
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*/
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#define scm_is_false_and_not_nil(x) (scm_is_eq ((x), SCM_BOOL_F))
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#define scm_is_true_or_nil(x) (!scm_is_eq ((x), SCM_BOOL_F))
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/*
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* Use these macros if #nil will never be tested,
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* for increased efficiency.
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*/
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#define scm_is_false_assume_not_nil(x) (scm_is_eq ((x), SCM_BOOL_F))
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#define scm_is_true_assume_not_nil(x) (!scm_is_eq ((x), SCM_BOOL_F))
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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 scm.h for more information on
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* how the following macro works.
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*/
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#define scm_is_false_or_nil(x) \
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(SCM_MATCHES_BITS_IN_COMMON ((x), SCM_ELISP_NIL, SCM_BOOL_F))
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#define scm_is_true_and_not_nil(x) (!scm_is_false_or_nil (x))
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/* #nil is false. */
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#define scm_is_false(x) (scm_is_false_or_nil (x))
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#define scm_is_true(x) (!scm_is_false (x))
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/*
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* Since we know SCM_BOOL_F and SCM_BOOL_T differ by exactly one bit,
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* and that SCM_BOOL_F and SCM_ELISP_NIL differ by exactly one bit,
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* and that they of course can't be the same bit (or else SCM_BOOL_T
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* and SCM_ELISP_NIL be would equal), it follows that SCM_BOOL_T and
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* SCM_ELISP_NIL differ by exactly two bits, and these are the bits
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* which will be ignored by SCM_MATCHES_BITS_IN_COMMON below.
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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 scm.h for more information.
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*
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* If SCM_ENABLE_ELISP is true, then scm_is_bool_or_nil(x)
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* returns 1 if and only if x is one of the following: SCM_BOOL_F,
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* SCM_BOOL_T, SCM_ELISP_NIL, or SCM_XXX_ANOTHER_BOOLEAN_DONT_USE_0.
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* Otherwise, it returns 0.
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*/
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#define scm_is_bool_or_nil(x) \
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(SCM_MATCHES_BITS_IN_COMMON ((x), SCM_BOOL_T, SCM_ELISP_NIL))
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#define scm_is_bool_and_not_nil(x) \
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(SCM_MATCHES_BITS_IN_COMMON ((x), SCM_BOOL_F, SCM_BOOL_T))
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SCM_API int scm_is_bool (SCM);
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#define scm_is_bool(x) (scm_is_bool_or_nil (x))
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#define scm_from_bool(x) ((x) ? SCM_BOOL_T : SCM_BOOL_F)
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SCM_API int scm_to_bool (SCM x);
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/* Older spellings for the above routines, kept around for
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compatibility. */
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#define SCM_FALSEP(x) (scm_is_false (x))
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#define SCM_NFALSEP(x) (scm_is_true (x))
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#define SCM_BOOLP(x) (scm_is_bool (x))
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#define SCM_BOOL(x) (scm_from_bool (x))
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#define SCM_NEGATE_BOOL(f) (scm_from_bool (!(f)))
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#define SCM_BOOL_NOT(x) (scm_not (x))
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/*
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* The following macros efficiently implement boolean truth testing as
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* expected by most lisps, which treat '() aka SCM_EOL as false.
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*
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* Since we know SCM_ELISP_NIL and SCM_BOOL_F differ by exactly one
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* bit, and that SCM_ELISP_NIL and SCM_EOL differ by exactly one bit,
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* and that they of course can't be the same bit (or else SCM_BOOL_F
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* and SCM_EOL be would equal), it follows that SCM_BOOL_F and SCM_EOL
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* differ by exactly two bits, and these are the bits which will be
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* ignored by SCM_MATCHES_BITS_IN_COMMON below.
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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 scm.h for more information.
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*
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* scm_is_lisp_false(x) returns 1 if and only if x is one of the
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* following: SCM_BOOL_F, SCM_ELISP_NIL, SCM_EOL or
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* SCM_XXX_ANOTHER_LISP_FALSE_DONT_USE. Otherwise, it returns 0.
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*/
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#define scm_is_lisp_false(x) \
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(SCM_MATCHES_BITS_IN_COMMON ((x), SCM_BOOL_F, SCM_EOL))
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SCM_API SCM scm_not (SCM x);
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SCM_API SCM scm_boolean_p (SCM obj);
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SCM_API SCM scm_nil_p (SCM obj);
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#define SCM_VALIDATE_BOOL(pos, flag) \
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do { \
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SCM_ASSERT_TYPE (scm_is_bool (flag), flag, pos, FUNC_NAME, "boolean"); \
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} while (0)
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#define SCM_VALIDATE_BOOL_COPY(pos, flag, cvar) \
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do { \
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SCM_ASSERT (scm_is_bool (flag), flag, pos, FUNC_NAME); \
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cvar = scm_to_bool (flag); \
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} while (0)
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SCM_INTERNAL void scm_init_boolean (void);
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#endif /* SCM_BOOLEAN_H */
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