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/* Copyright (C) 1995,1996,1997,1998,2000,2001,2003, 2004 Free Software Foundation, Inc.
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*/
#if HAVE_CONFIG_H
# include <config.h>
#endif
#include "libguile/_scm.h"
#include "libguile/ramap.h"
#include "libguile/stackchk.h"
#include "libguile/strorder.h"
#include "libguile/async.h"
#include "libguile/root.h"
#include "libguile/smob.h"
#include "libguile/unif.h"
#include "libguile/vectors.h"
#include "libguile/validate.h"
#include "libguile/eq.h"
#ifdef HAVE_STRING_H
#include <string.h>
#endif
SCM_DEFINE1 (scm_eq_p, "eq?", scm_tc7_rpsubr,
(SCM x, SCM y),
"Return @code{#t} iff @var{x} references the same object as @var{y}.\n"
"@code{eq?} is similar to @code{eqv?} except that in some cases it is\n"
"capable of discerning distinctions finer than those detectable by\n"
"@code{eqv?}.")
#define FUNC_NAME s_scm_eq_p
{
return scm_from_bool (scm_is_eq (x, y));
}
#undef FUNC_NAME
/* We compare doubles in a special way for 'eqv?' to be able to
distinguish plus and minus zero and to identify NaNs.
*/
static int
real_eqv (double x, double y)
{
return !memcmp (&x, &y, sizeof(double)) || (x != x && y != y);
}
#include <stdio.h>
SCM_PRIMITIVE_GENERIC_1 (scm_eqv_p, "eqv?", scm_tc7_rpsubr,
(SCM x, SCM y),
"The @code{eqv?} procedure defines a useful equivalence relation on objects.\n"
"Briefly, it returns @code{#t} if @var{x} and @var{y} should normally be\n"
"regarded as the same object. This relation is left slightly open to\n"
"interpretation, but works for comparing immediate integers, characters,\n"
"and inexact numbers.")
#define FUNC_NAME s_scm_eqv_p
{
if (scm_is_eq (x, y))
return SCM_BOOL_T;
if (SCM_IMP (x))
return SCM_BOOL_F;
if (SCM_IMP (y))
return SCM_BOOL_F;
/* this ensures that types and scm_length are the same. */
if (SCM_CELL_TYPE (x) != SCM_CELL_TYPE (y))
{
/* fractions use 0x10000 as a flag (at the suggestion of Marius Vollmer),
but this checks the entire type word, so fractions may be accidentally
flagged here as unequal. Perhaps I should use the 4th double_cell word?
*/
/* treat mixes of real and complex types specially */
if (SCM_INEXACTP (x))
{
if (SCM_REALP (x))
return scm_from_bool (SCM_COMPLEXP (y)
&& real_eqv (SCM_REAL_VALUE (x),
SCM_COMPLEX_REAL (y))
&& SCM_COMPLEX_IMAG (y) == 0.0);
else
return scm_from_bool (SCM_REALP (y)
&& real_eqv (SCM_COMPLEX_REAL (x),
SCM_REAL_VALUE (y))
&& SCM_COMPLEX_IMAG (x) == 0.0);
}
if (SCM_FRACTIONP (x) && SCM_FRACTIONP (y))
return scm_i_fraction_equalp (x, y);
return SCM_BOOL_F;
}
if (SCM_NUMP (x))
{
if (SCM_BIGP (x)) {
return scm_from_bool (scm_i_bigcmp (x, y) == 0);
} else if (SCM_REALP (x)) {
return scm_from_bool (real_eqv (SCM_REAL_VALUE (x), SCM_REAL_VALUE (y)));
} else if (SCM_FRACTIONP (x)) {
return scm_i_fraction_equalp (x, y);
} else { /* complex */
return scm_from_bool (real_eqv (SCM_COMPLEX_REAL (x),
SCM_COMPLEX_REAL (y))
&& real_eqv (SCM_COMPLEX_IMAG (x),
SCM_COMPLEX_IMAG (y)));
}
}
if (SCM_UNPACK (g_scm_eqv_p))
return scm_call_generic_2 (g_scm_eqv_p, x, y);
else
return SCM_BOOL_F;
}
#undef FUNC_NAME
SCM_PRIMITIVE_GENERIC_1 (scm_equal_p, "equal?", scm_tc7_rpsubr,
(SCM x, SCM y),
"Return @code{#t} iff @var{x} and @var{y} are recursively @code{eqv?} equivalent.\n"
"@code{equal?} recursively compares the contents of pairs,\n"
"vectors, and strings, applying @code{eqv?} on other objects such as\n"
"numbers and symbols. A rule of thumb is that objects are generally\n"
"@code{equal?} if they print the same. @code{equal?} may fail to\n"
"terminate if its arguments are circular data structures.")
#define FUNC_NAME s_scm_equal_p
{
SCM_CHECK_STACK;
tailrecurse:
SCM_TICK;
if (scm_is_eq (x, y))
return SCM_BOOL_T;
if (SCM_IMP (x))
return SCM_BOOL_F;
if (SCM_IMP (y))
return SCM_BOOL_F;
if (scm_is_pair (x) && scm_is_pair (y))
{
if (scm_is_false (scm_equal_p (SCM_CAR (x), SCM_CAR (y))))
return SCM_BOOL_F;
x = SCM_CDR(x);
y = SCM_CDR(y);
goto tailrecurse;
}
if (SCM_TYP7 (x) == scm_tc7_string && SCM_TYP7 (y) == scm_tc7_string)
return scm_string_equal_p (x, y);
if (SCM_TYP7 (x) == scm_tc7_smob && SCM_TYP16 (x) == SCM_TYP16 (y))
{
int i = SCM_SMOBNUM (x);
if (!(i < scm_numsmob))
return SCM_BOOL_F;
if (scm_smobs[i].equalp)
return (scm_smobs[i].equalp) (x, y);
else
goto generic_equal;
}
/* This ensures that types and scm_length are the same. */
if (SCM_CELL_TYPE (x) != SCM_CELL_TYPE (y))
{
/* treat mixes of real and complex types specially */
if (SCM_INEXACTP (x) && SCM_INEXACTP (y))
{
if (SCM_REALP (x))
return scm_from_bool (SCM_COMPLEXP (y)
&& SCM_REAL_VALUE (x) == SCM_COMPLEX_REAL (y)
&& SCM_COMPLEX_IMAG (y) == 0.0);
else
return scm_from_bool (SCM_REALP (y)
&& SCM_COMPLEX_REAL (x) == SCM_REAL_VALUE (y)
&& SCM_COMPLEX_IMAG (x) == 0.0);
}
return SCM_BOOL_F;
}
switch (SCM_TYP7 (x))
{
default:
break;
case scm_tc7_number:
switch SCM_TYP16 (x)
{
case scm_tc16_big:
return scm_bigequal (x, y);
case scm_tc16_real:
return scm_real_equalp (x, y);
case scm_tc16_complex:
return scm_complex_equalp (x, y);
case scm_tc16_fraction:
return scm_i_fraction_equalp (x, y);
}
case scm_tc7_vector:
case scm_tc7_wvect:
return scm_vector_equal_p (x, y);
}
generic_equal:
if (SCM_UNPACK (g_scm_equal_p))
return scm_call_generic_2 (g_scm_equal_p, x, y);
else
return SCM_BOOL_F;
}
#undef FUNC_NAME
void
scm_init_eq ()
{
#include "libguile/eq.x"
}
/*
Local Variables:
c-file-style: "gnu"
End:
*/
|