add FSF header.
[bpt/guile.git] / libguile / eq.c
CommitLineData
2b829bbb 1/* Copyright (C) 1995,1996,1997,1998,2000,2001,2003, 2004, 2006 Free Software Foundation, Inc.
0f2d19dd 2 *
73be1d9e
MV
3 * This library is free software; you can redistribute it and/or
4 * modify it under the terms of the GNU Lesser General Public
5 * License as published by the Free Software Foundation; either
6 * version 2.1 of the License, or (at your option) any later version.
0f2d19dd 7 *
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8 * This library is distributed in the hope that it will be useful,
9 * but 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.
0f2d19dd 12 *
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MV
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
92205699 15 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
73be1d9e 16 */
1bbd0b84 17
0f2d19dd 18\f
1f4d02c2
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19#if HAVE_CONFIG_H
20# include <config.h>
21#endif
9540b68f 22
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23#include "libguile/_scm.h"
24#include "libguile/ramap.h"
25#include "libguile/stackchk.h"
26#include "libguile/strorder.h"
27#include "libguile/async.h"
28#include "libguile/root.h"
29#include "libguile/smob.h"
30#include "libguile/unif.h"
31#include "libguile/vectors.h"
0f2d19dd 32
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LC
33#include "libguile/struct.h"
34#include "libguile/goops.h"
35#include "libguile/objects.h"
36
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MD
37#include "libguile/validate.h"
38#include "libguile/eq.h"
0f2d19dd 39\f
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40
41#ifdef HAVE_STRING_H
42#include <string.h>
43#endif
44\f
45
c3ee7520 46SCM_DEFINE1 (scm_eq_p, "eq?", scm_tc7_rpsubr,
1bbd0b84 47 (SCM x, SCM y),
602d32dd
KR
48 "Return @code{#t} if @var{x} and @var{y} are the same object,\n"
49 "except for numbers and characters. For example,\n"
50 "\n"
51 "@example\n"
52 "(define x (vector 1 2 3))\n"
53 "(define y (vector 1 2 3))\n"
54 "\n"
55 "(eq? x x) @result{} #t\n"
56 "(eq? x y) @result{} #f\n"
57 "@end example\n"
58 "\n"
59 "Numbers and characters are not equal to any other object, but\n"
60 "the problem is they're not necessarily @code{eq?} to themselves\n"
61 "either. This is even so when the number comes directly from a\n"
62 "variable,\n"
63 "\n"
64 "@example\n"
65 "(let ((n (+ 2 3)))\n"
66 " (eq? n n)) @result{} *unspecified*\n"
67 "@end example\n"
68 "\n"
69 "Generally @code{eqv?} should be used when comparing numbers or\n"
70 "characters. @code{=} or @code{char=?} can be used too.\n"
71 "\n"
4450a227
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72 "It's worth noting that end-of-list @code{()}, @code{#t},\n"
73 "@code{#f}, a symbol of a given name, and a keyword of a given\n"
74 "name, are unique objects. There's just one of each, so for\n"
75 "instance no matter how @code{()} arises in a program, it's the\n"
76 "same object and can be compared with @code{eq?},\n"
602d32dd
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77 "\n"
78 "@example\n"
79 "(define x (cdr '(123)))\n"
80 "(define y (cdr '(456)))\n"
81 "(eq? x y) @result{} #t\n"
82 "\n"
4450a227 83 "(define x (string->symbol \"foo\"))\n"
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84 "(eq? x 'foo) @result{} #t\n"
85 "@end example")
1bbd0b84 86#define FUNC_NAME s_scm_eq_p
0f2d19dd 87{
bc36d050 88 return scm_from_bool (scm_is_eq (x, y));
0f2d19dd 89}
1bbd0b84 90#undef FUNC_NAME
0f2d19dd 91
96d00047
MV
92/* We compare doubles in a special way for 'eqv?' to be able to
93 distinguish plus and minus zero and to identify NaNs.
94*/
95
96static int
97real_eqv (double x, double y)
98{
0e12d408 99 return !memcmp (&x, &y, sizeof(double)) || (x != x && y != y);
96d00047 100}
0f2d19dd 101
f92e85f7 102#include <stdio.h>
47cd67db 103SCM_PRIMITIVE_GENERIC_1 (scm_eqv_p, "eqv?", scm_tc7_rpsubr,
1bbd0b84 104 (SCM x, SCM y),
602d32dd
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105 "Return @code{#t} if @var{x} and @var{y} are the same object, or\n"
106 "for characters and numbers the same value.\n"
107 "\n"
108 "On objects except characters and numbers, @code{eqv?} is the\n"
109 "same as @code{eq?}, it's true if @var{x} and @var{y} are the\n"
110 "same object.\n"
111 "\n"
112 "If @var{x} and @var{y} are numbers or characters, @code{eqv?}\n"
113 "compares their type and value. An exact number is not\n"
114 "@code{eqv?} to an inexact number (even if their value is the\n"
115 "same).\n"
116 "\n"
117 "@example\n"
118 "(eqv? 3 (+ 1 2)) @result{} #t\n"
119 "(eqv? 1 1.0) @result{} #f\n"
120 "@end example")
1bbd0b84 121#define FUNC_NAME s_scm_eqv_p
0f2d19dd 122{
bc36d050 123 if (scm_is_eq (x, y))
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124 return SCM_BOOL_T;
125 if (SCM_IMP (x))
126 return SCM_BOOL_F;
127 if (SCM_IMP (y))
128 return SCM_BOOL_F;
0f2d19dd 129 /* this ensures that types and scm_length are the same. */
f92e85f7 130
fbd485ba 131 if (SCM_CELL_TYPE (x) != SCM_CELL_TYPE (y))
950cc72b 132 {
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133 /* fractions use 0x10000 as a flag (at the suggestion of Marius Vollmer),
134 but this checks the entire type word, so fractions may be accidentally
135 flagged here as unequal. Perhaps I should use the 4th double_cell word?
136 */
137
950cc72b 138 /* treat mixes of real and complex types specially */
6b412e91 139 if (SCM_INEXACTP (x))
950cc72b 140 {
6b412e91 141 if (SCM_REALP (x))
7888309b 142 return scm_from_bool (SCM_COMPLEXP (y)
96d00047
MV
143 && real_eqv (SCM_REAL_VALUE (x),
144 SCM_COMPLEX_REAL (y))
6b412e91 145 && SCM_COMPLEX_IMAG (y) == 0.0);
950cc72b 146 else
7888309b 147 return scm_from_bool (SCM_REALP (y)
96d00047
MV
148 && real_eqv (SCM_COMPLEX_REAL (x),
149 SCM_REAL_VALUE (y))
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150 && SCM_COMPLEX_IMAG (x) == 0.0);
151 }
f92e85f7
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152
153 if (SCM_FRACTIONP (x) && SCM_FRACTIONP (y))
154 return scm_i_fraction_equalp (x, y);
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155 return SCM_BOOL_F;
156 }
157 if (SCM_NUMP (x))
158 {
eb42e2f0 159 if (SCM_BIGP (x)) {
7888309b 160 return scm_from_bool (scm_i_bigcmp (x, y) == 0);
6b412e91 161 } else if (SCM_REALP (x)) {
7888309b 162 return scm_from_bool (real_eqv (SCM_REAL_VALUE (x), SCM_REAL_VALUE (y)));
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163 } else if (SCM_FRACTIONP (x)) {
164 return scm_i_fraction_equalp (x, y);
eb42e2f0 165 } else { /* complex */
7888309b 166 return scm_from_bool (real_eqv (SCM_COMPLEX_REAL (x),
96d00047
MV
167 SCM_COMPLEX_REAL (y))
168 && real_eqv (SCM_COMPLEX_IMAG (x),
169 SCM_COMPLEX_IMAG (y)));
eb42e2f0 170 }
950cc72b 171 }
47cd67db
MD
172 if (SCM_UNPACK (g_scm_eqv_p))
173 return scm_call_generic_2 (g_scm_eqv_p, x, y);
174 else
175 return SCM_BOOL_F;
0f2d19dd 176}
1bbd0b84 177#undef FUNC_NAME
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178
179
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180SCM_PRIMITIVE_GENERIC_1 (scm_equal_p, "equal?", scm_tc7_rpsubr,
181 (SCM x, SCM y),
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182 "Return @code{#t} if @var{x} and @var{y} are the same type, and\n"
183 "their contents or value are equal.\n"
184 "\n"
185 "For a pair, string, vector or array, @code{equal?} compares the\n"
186 "contents, and does so using using the same @code{equal?}\n"
187 "recursively, so a deep structure can be traversed.\n"
188 "\n"
189 "@example\n"
190 "(equal? (list 1 2 3) (list 1 2 3)) @result{} #t\n"
191 "(equal? (list 1 2 3) (vector 1 2 3)) @result{} #f\n"
192 "@end example\n"
193 "\n"
194 "For other objects, @code{equal?} compares as per @code{eqv?},\n"
195 "which means characters and numbers are compared by type and\n"
196 "value (and like @code{eqv?}, exact and inexact numbers are not\n"
197 "@code{equal?}, even if their value is the same).\n"
198 "\n"
199 "@example\n"
200 "(equal? 3 (+ 1 2)) @result{} #t\n"
201 "(equal? 1 1.0) @result{} #f\n"
202 "@end example\n"
203 "\n"
204 "Hash tables are currently only compared as per @code{eq?}, so\n"
205 "two different tables are not @code{equal?}, even if their\n"
206 "contents are the same.\n"
207 "\n"
208 "@code{equal?} does not support circular data structures, it may\n"
209 "go into an infinite loop if asked to compare two circular lists\n"
210 "or similar.\n"
211 "\n"
212 "New application-defined object types (Smobs) have an\n"
213 "@code{equalp} handler which is called by @code{equal?}. This\n"
214 "lets an application traverse the contents or control what is\n"
215 "considered @code{equal?} for two such objects. If there's no\n"
216 "handler, the default is to just compare as per @code{eq?}.")
1bbd0b84 217#define FUNC_NAME s_scm_equal_p
0f2d19dd
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218{
219 SCM_CHECK_STACK;
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220 tailrecurse:
221 SCM_TICK;
bc36d050 222 if (scm_is_eq (x, y))
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223 return SCM_BOOL_T;
224 if (SCM_IMP (x))
225 return SCM_BOOL_F;
226 if (SCM_IMP (y))
227 return SCM_BOOL_F;
d2e53ed6 228 if (scm_is_pair (x) && scm_is_pair (y))
950cc72b 229 {
7888309b 230 if (scm_is_false (scm_equal_p (SCM_CAR (x), SCM_CAR (y))))
950cc72b
MD
231 return SCM_BOOL_F;
232 x = SCM_CDR(x);
233 y = SCM_CDR(y);
234 goto tailrecurse;
235 }
baa84a20 236 if (SCM_TYP7 (x) == scm_tc7_string && SCM_TYP7 (y) == scm_tc7_string)
950cc72b 237 return scm_string_equal_p (x, y);
789d2fc8
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238 if (SCM_TYP7 (x) == scm_tc7_smob && SCM_TYP16 (x) == SCM_TYP16 (y))
239 {
240 int i = SCM_SMOBNUM (x);
241 if (!(i < scm_numsmob))
242 return SCM_BOOL_F;
243 if (scm_smobs[i].equalp)
244 return (scm_smobs[i].equalp) (x, y);
245 else
246 goto generic_equal;
247 }
950cc72b 248 /* This ensures that types and scm_length are the same. */
fbd485ba 249 if (SCM_CELL_TYPE (x) != SCM_CELL_TYPE (y))
950cc72b
MD
250 {
251 /* treat mixes of real and complex types specially */
f92e85f7 252 if (SCM_INEXACTP (x) && SCM_INEXACTP (y))
950cc72b 253 {
6b412e91 254 if (SCM_REALP (x))
7888309b 255 return scm_from_bool (SCM_COMPLEXP (y)
950cc72b 256 && SCM_REAL_VALUE (x) == SCM_COMPLEX_REAL (y)
6b412e91 257 && SCM_COMPLEX_IMAG (y) == 0.0);
950cc72b 258 else
7888309b 259 return scm_from_bool (SCM_REALP (y)
950cc72b
MD
260 && SCM_COMPLEX_REAL (x) == SCM_REAL_VALUE (y)
261 && SCM_COMPLEX_IMAG (x) == 0.0);
0f2d19dd 262 }
f92e85f7 263
af4f8612
MV
264 /* Vectors can be equal to one-dimensional arrays.
265 */
266 if (SCM_I_ARRAYP (x) || SCM_I_ARRAYP (y))
267 return scm_array_equal_p (x, y);
268
950cc72b
MD
269 return SCM_BOOL_F;
270 }
271 switch (SCM_TYP7 (x))
272 {
273 default:
a48d60b1 274 break;
534c55a9
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275 case scm_tc7_number:
276 switch SCM_TYP16 (x)
277 {
278 case scm_tc16_big:
279 return scm_bigequal (x, y);
280 case scm_tc16_real:
281 return scm_real_equalp (x, y);
282 case scm_tc16_complex:
283 return scm_complex_equalp (x, y);
f92e85f7
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284 case scm_tc16_fraction:
285 return scm_i_fraction_equalp (x, y);
534c55a9 286 }
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287 case scm_tc7_vector:
288 case scm_tc7_wvect:
354116f7 289 return scm_i_vector_equal_p (x, y);
950cc72b 290 }
d15ad007
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291
292 /* Check equality between structs of equal type (see cell-type test above)
293 that are not GOOPS instances. GOOPS instances are treated via the
294 generic function. */
295 if ((SCM_STRUCTP (x)) && (!SCM_INSTANCEP (x)))
296 return scm_i_struct_equalp (x, y);
297
789d2fc8 298 generic_equal:
a48d60b1
MD
299 if (SCM_UNPACK (g_scm_equal_p))
300 return scm_call_generic_2 (g_scm_equal_p, x, y);
301 else
302 return SCM_BOOL_F;
0f2d19dd 303}
1bbd0b84 304#undef FUNC_NAME
0f2d19dd
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305
306
307\f
308
309
1cc91f1b 310
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311void
312scm_init_eq ()
0f2d19dd 313{
a0599745 314#include "libguile/eq.x"
0f2d19dd
JB
315}
316
89e00824
ML
317
318/*
319 Local Variables:
320 c-file-style: "gnu"
321 End:
322*/