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+/* Copyright 1995-1998,2000-2001,2003-2004,2006,2009-2011,2017-2018
+ Free Software Foundation, Inc.
+
+ This file is part of Guile.
+
+ Guile 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 3 of the License, or
+ (at your option) any later version.
+
+ Guile 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 Guile. If not, see
+ <https://www.gnu.org/licenses/>. */
+
+
+#ifdef HAVE_CONFIG_H
+# include <config.h>
+#endif
+
+#include <math.h>
+#include <string.h>
+
+#include "array-map.h"
+#include "async.h"
+#include "bitvectors.h"
+#include "boolean.h"
+#include "bytevectors.h"
+#include "eval.h"
+#include "foreign.h"
+#include "generalized-arrays.h"
+#include "goops.h"
+#include "gsubr.h"
+#include "hashtab.h"
+#include "pairs.h"
+#include "private-options.h"
+#include "smob.h"
+#include "stackchk.h"
+#include "strorder.h"
+#include "struct.h"
+#include "syntax.h"
+#include "vectors.h"
+
+#include "eq.h"
+
+
+
+
+static SCM scm_i_eq_p (SCM x, SCM y, SCM rest);
+SCM_DEFINE (scm_i_eq_p, "eq?", 0, 2, 1,
+ (SCM x, SCM y, SCM rest),
+ "Return @code{#t} if @var{x} and @var{y} are the same object,\n"
+ "except for numbers and characters. For example,\n"
+ "\n"
+ "@example\n"
+ "(define x (vector 1 2 3))\n"
+ "(define y (vector 1 2 3))\n"
+ "\n"
+ "(eq? x x) @result{} #t\n"
+ "(eq? x y) @result{} #f\n"
+ "@end example\n"
+ "\n"
+ "Numbers and characters are not equal to any other object, but\n"
+ "the problem is they're not necessarily @code{eq?} to themselves\n"
+ "either. This is even so when the number comes directly from a\n"
+ "variable,\n"
+ "\n"
+ "@example\n"
+ "(let ((n (+ 2 3)))\n"
+ " (eq? n n)) @result{} *unspecified*\n"
+ "@end example\n"
+ "\n"
+ "Generally @code{eqv?} should be used when comparing numbers or\n"
+ "characters. @code{=} or @code{char=?} can be used too.\n"
+ "\n"
+ "It's worth noting that end-of-list @code{()}, @code{#t},\n"
+ "@code{#f}, a symbol of a given name, and a keyword of a given\n"
+ "name, are unique objects. There's just one of each, so for\n"
+ "instance no matter how @code{()} arises in a program, it's the\n"
+ "same object and can be compared with @code{eq?},\n"
+ "\n"
+ "@example\n"
+ "(define x (cdr '(123)))\n"
+ "(define y (cdr '(456)))\n"
+ "(eq? x y) @result{} #t\n"
+ "\n"
+ "(define x (string->symbol \"foo\"))\n"
+ "(eq? x 'foo) @result{} #t\n"
+ "@end example")
+#define FUNC_NAME s_scm_i_eq_p
+{
+ if (SCM_UNBNDP (x) || SCM_UNBNDP (y))
+ return SCM_BOOL_T;
+ while (scm_is_pair (rest))
+ {
+ if (!scm_is_eq (x, y))
+ return SCM_BOOL_F;
+ x = y;
+ y = scm_car (rest);
+ rest = scm_cdr (rest);
+ }
+ return scm_from_bool (scm_is_eq (x, y));
+}
+#undef FUNC_NAME
+
+SCM
+scm_eq_p (SCM x, SCM y)
+{
+ return scm_from_bool (scm_is_eq (x, y));
+}
+
+/* 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))
+ || (SCM_UNLIKELY (isnan (x)) && SCM_UNLIKELY (isnan (y)));
+}
+
+SCM
+scm_real_equalp (SCM x, SCM y)
+{
+ return scm_from_bool (real_eqv (SCM_REAL_VALUE (x),
+ SCM_REAL_VALUE (y)));
+}
+
+SCM
+scm_bigequal (SCM x, SCM y)
+{
+ return scm_from_bool (scm_i_bigcmp (x, y) == 0);
+}
+
+SCM
+scm_complex_equalp (SCM x, SCM y)
+{
+ return scm_from_bool (real_eqv (SCM_COMPLEX_REAL (x),
+ SCM_COMPLEX_REAL (y))
+ && real_eqv (SCM_COMPLEX_IMAG (x),
+ SCM_COMPLEX_IMAG (y)));
+}
+
+SCM
+scm_i_fraction_equalp (SCM x, SCM y)
+{
+ return scm_from_bool
+ (scm_is_true (scm_equal_p (SCM_FRACTION_NUMERATOR (x),
+ SCM_FRACTION_NUMERATOR (y)))
+ && scm_is_true (scm_equal_p (SCM_FRACTION_DENOMINATOR (x),
+ SCM_FRACTION_DENOMINATOR (y))));
+}
+
+int
+scm_i_heap_numbers_equal_p (SCM x, SCM y)
+{
+ if (SCM_IMP (x)) abort();
+ switch (SCM_TYP16 (x))
+ {
+ case scm_tc16_big:
+ return scm_is_true (scm_bigequal (x, y));
+ case scm_tc16_real:
+ return scm_is_true (scm_real_equalp (x, y));
+ case scm_tc16_complex:
+ return scm_is_true (scm_complex_equalp (x, y));
+ case scm_tc16_fraction:
+ return scm_is_true (scm_i_fraction_equalp (x, y));
+ default:
+ abort ();
+ }
+}
+
+static SCM scm_i_eqv_p (SCM x, SCM y, SCM rest);
+#include <stdio.h>
+SCM_DEFINE (scm_i_eqv_p, "eqv?", 0, 2, 1,
+ (SCM x, SCM y, SCM rest),
+ "Return @code{#t} if @var{x} and @var{y} are the same object, or\n"
+ "for characters and numbers the same value.\n"
+ "\n"
+ "On objects except characters and numbers, @code{eqv?} is the\n"
+ "same as @code{eq?}, it's true if @var{x} and @var{y} are the\n"
+ "same object.\n"
+ "\n"
+ "If @var{x} and @var{y} are numbers or characters, @code{eqv?}\n"
+ "compares their type and value. An exact number is not\n"
+ "@code{eqv?} to an inexact number (even if their value is the\n"
+ "same).\n"
+ "\n"
+ "@example\n"
+ "(eqv? 3 (+ 1 2)) @result{} #t\n"
+ "(eqv? 1 1.0) @result{} #f\n"
+ "@end example")
+#define FUNC_NAME s_scm_i_eqv_p
+{
+ if (SCM_UNBNDP (x) || SCM_UNBNDP (y))
+ return SCM_BOOL_T;
+ while (!scm_is_null (rest))
+ {
+ if (!scm_is_true (scm_eqv_p (x, y)))
+ return SCM_BOOL_F;
+ x = y;
+ y = scm_car (rest);
+ rest = scm_cdr (rest);
+ }
+ return scm_eqv_p (x, y);
+}
+#undef FUNC_NAME
+
+SCM scm_eqv_p (SCM x, SCM y)
+#define FUNC_NAME s_scm_i_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))
+ return SCM_BOOL_F;
+ switch (SCM_TYP7 (x))
+ {
+ default:
+ break;
+ case scm_tc7_number:
+ return scm_from_bool (scm_i_heap_numbers_equal_p (x, y));
+ }
+ return SCM_BOOL_F;
+}
+#undef FUNC_NAME
+
+
+static SCM scm_i_equal_p (SCM, SCM, SCM);
+SCM_PRIMITIVE_GENERIC (scm_i_equal_p, "equal?", 0, 2, 1,
+ (SCM x, SCM y, SCM rest),
+ "Return @code{#t} if @var{x} and @var{y} are the same type, and\n"
+ "their contents or value are equal.\n"
+ "\n"
+ "For a pair, string, vector or array, @code{equal?} compares the\n"
+ "contents, and does so using using the same @code{equal?}\n"
+ "recursively, so a deep structure can be traversed.\n"
+ "\n"
+ "@example\n"
+ "(equal? (list 1 2 3) (list 1 2 3)) @result{} #t\n"
+ "(equal? (list 1 2 3) (vector 1 2 3)) @result{} #f\n"
+ "@end example\n"
+ "\n"
+ "For other objects, @code{equal?} compares as per @code{eqv?},\n"
+ "which means characters and numbers are compared by type and\n"
+ "value (and like @code{eqv?}, exact and inexact numbers are not\n"
+ "@code{equal?}, even if their value is the same).\n"
+ "\n"
+ "@example\n"
+ "(equal? 3 (+ 1 2)) @result{} #t\n"
+ "(equal? 1 1.0) @result{} #f\n"
+ "@end example\n"
+ "\n"
+ "Hash tables are currently only compared as per @code{eq?}, so\n"
+ "two different tables are not @code{equal?}, even if their\n"
+ "contents are the same.\n"
+ "\n"
+ "@code{equal?} does not support circular data structures, it may\n"
+ "go into an infinite loop if asked to compare two circular lists\n"
+ "or similar.\n"
+ "\n"
+ "New application-defined object types (Smobs) have an\n"
+ "@code{equalp} handler which is called by @code{equal?}. This\n"
+ "lets an application traverse the contents or control what is\n"
+ "considered @code{equal?} for two such objects. If there's no\n"
+ "handler, the default is to just compare as per @code{eq?}.")
+#define FUNC_NAME s_scm_i_equal_p
+{
+ if (SCM_UNBNDP (x) || SCM_UNBNDP (y))
+ return SCM_BOOL_T;
+ while (!scm_is_null (rest))
+ {
+ if (!scm_is_true (scm_equal_p (x, y)))
+ return SCM_BOOL_F;
+ x = y;
+ y = scm_car (rest);
+ rest = SCM_CDR (rest);
+ }
+ return scm_equal_p (x, y);
+}
+#undef FUNC_NAME
+
+SCM
+scm_equal_p (SCM x, SCM y)
+#define FUNC_NAME s_scm_i_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_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))
+ {
+ /* Vectors can be equal to one-dimensional arrays.
+ */
+ if (scm_is_array (x) && scm_is_array (y))
+ return scm_array_equal_p (x, y);
+
+ return SCM_BOOL_F;
+ }
+ switch (SCM_TYP7 (x))
+ {
+ default:
+ /* Check equality between structs of equal type (see cell-type test above). */
+ if (SCM_STRUCTP (x))
+ {
+ if (SCM_INSTANCEP (x))
+ goto generic_equal;
+ else
+ return scm_i_struct_equalp (x, y);
+ }
+ 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);
+ default:
+ /* assert not reached? */
+ return SCM_BOOL_F;
+ }
+ case scm_tc7_pointer:
+ return scm_from_bool (SCM_POINTER_VALUE (x) == SCM_POINTER_VALUE (y));
+ case scm_tc7_string:
+ return scm_string_equal_p (x, y);
+ case scm_tc7_bytevector:
+ return scm_bytevector_eq_p (x, y);
+ case scm_tc7_array:
+ return scm_array_equal_p (x, y);
+ case scm_tc7_bitvector:
+ return scm_i_bitvector_equal_p (x, y);
+ case scm_tc7_vector:
+ case scm_tc7_wvect:
+ return scm_i_vector_equal_p (x, y);
+ case scm_tc7_syntax:
+ if (scm_is_false (scm_equal_p (scm_syntax_wrap (x),
+ scm_syntax_wrap (y))))
+ return SCM_BOOL_F;
+ if (scm_is_false (scm_equal_p (scm_syntax_module (x),
+ scm_syntax_module (y))))
+ return SCM_BOOL_F;
+ x = scm_syntax_expression (x);
+ y = scm_syntax_expression (y);
+ goto tailrecurse;
+ }
+
+ /* Otherwise just return false. Dispatching to the generic is the wrong thing
+ here, as we can hit this case for any two objects of the same type that we
+ think are distinct, like different symbols. */
+ return SCM_BOOL_F;
+
+ generic_equal:
+ if (SCM_UNPACK (g_scm_i_equal_p))
+ return scm_call_2 (g_scm_i_equal_p, x, y);
+ else
+ return SCM_BOOL_F;
+}
+#undef FUNC_NAME
+
+
+
+
+
+
+void
+scm_init_eq ()
+{
+#include "eq.x"
+}
+