libguile/eq.c

   1 /* Copyright (C) 1995,1996,1997,1998,2000,2001, 2003 Free Software Foundation, Inc.
   2  *
   3  * This program is free software; you can redistribute it and/or modify
   4  * it under the terms of the GNU General Public License as published by
   5  * the Free Software Foundation; either version 2, or (at your option)
   6  * any later version.
   7  *
   8  * This program 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
  11  * GNU General Public License for more details.
  12  *
  13  * You should have received a copy of the GNU General Public License
  14  * along with this software; see the file COPYING.  If not, write to
  15  * the Free Software Foundation, Inc., 59 Temple Place, Suite 330,
  16  * Boston, MA 02111-1307 USA
  17  *
  18  * As a special exception, the Free Software Foundation gives permission
  19  * for additional uses of the text contained in its release of GUILE.
  20  *
  21  * The exception is that, if you link the GUILE library with other files
  22  * to produce an executable, this does not by itself cause the
  23  * resulting executable to be covered by the GNU General Public License.
  24  * Your use of that executable is in no way restricted on account of
  25  * linking the GUILE library code into it.
  26  *
  27  * This exception does not however invalidate any other reasons why
  28  * the executable file might be covered by the GNU General Public License.
  29  *
  30  * This exception applies only to the code released by the
  31  * Free Software Foundation under the name GUILE.  If you copy
  32  * code from other Free Software Foundation releases into a copy of
  33  * GUILE, as the General Public License permits, the exception does
  34  * not apply to the code that you add in this way.  To avoid misleading
  35  * anyone as to the status of such modified files, you must delete
  36  * this exception notice from them.
  37  *
  38  * If you write modifications of your own for GUILE, it is your choice
  39  * whether to permit this exception to apply to your modifications.
  40  * If you do not wish that, delete this exception notice.  */
  41
  42 \f
  43 #if HAVE_CONFIG_H
  44 #  include <config.h>
  45 #endif
  46
  47 #include "libguile/_scm.h"
  48 #include "libguile/ramap.h"
  49 #include "libguile/stackchk.h"
  50 #include "libguile/strorder.h"
  51 #include "libguile/async.h"
  52 #include "libguile/root.h"
  53 #include "libguile/smob.h"
  54 #include "libguile/unif.h"
  55 #include "libguile/vectors.h"
  56
  57 #include "libguile/validate.h"
  58 #include "libguile/eq.h"
  59 \f
  60
  61 #ifdef HAVE_STRING_H
  62 #include <string.h>
  63 #endif
  64 \f
  65
  66 SCM_DEFINE1 (scm_eq_p, "eq?", scm_tc7_rpsubr,
  67              (SCM x, SCM y),
  68              "Return @code{#t} iff @var{x} references the same object as @var{y}.\n"
  69              "@code{eq?} is similar to @code{eqv?} except that in some cases it is\n"
  70              "capable of discerning distinctions finer than those detectable by\n"
  71              "@code{eqv?}.")
  72 #define FUNC_NAME s_scm_eq_p
  73 {
  74   return SCM_BOOL (SCM_EQ_P (x, y));
  75 }
  76 #undef FUNC_NAME
  77
  78 /* We compare doubles in a special way for 'eqv?' to be able to
  79    distinguish plus and minus zero and to identify NaNs.
  80 */
  81
  82 static int
  83 real_eqv (double x, double y)
  84 {
  85   return !memcmp (&x, &y, sizeof(double));
  86 }
  87
  88 SCM_DEFINE1 (scm_eqv_p, "eqv?", scm_tc7_rpsubr,
  89              (SCM x, SCM y),
  90              "The @code{eqv?} procedure defines a useful equivalence relation on objects.\n"
  91              "Briefly, it returns @code{#t} if @var{x} and @var{y} should normally be\n"
  92              "regarded as the same object.  This relation is left slightly open to\n"
  93              "interpretation, but works for comparing immediate integers, characters,\n"
  94              "and inexact numbers.")
  95 #define FUNC_NAME s_scm_eqv_p
  96 {
  97   if (SCM_EQ_P (x, y))
  98     return SCM_BOOL_T;
  99   if (SCM_IMP (x))
 100     return SCM_BOOL_F;
 101   if (SCM_IMP (y))
 102     return SCM_BOOL_F;
 103   /* this ensures that types and scm_length are the same. */
 104   if (SCM_CELL_TYPE (x) != SCM_CELL_TYPE (y))
 105     {
 106       /* treat mixes of real and complex types specially */
 107       if (SCM_SLOPPY_INEXACTP (x))
 108         {
 109           if (SCM_SLOPPY_REALP (x))
 110             return SCM_BOOL (SCM_SLOPPY_COMPLEXP (y)
 111                              && real_eqv (SCM_REAL_VALUE (x),
 112                                           SCM_COMPLEX_REAL (y))
 113                              && 0.0 == SCM_COMPLEX_IMAG (y));
 114           else
 115             return SCM_BOOL (SCM_SLOPPY_REALP (y)
 116                              && real_eqv (SCM_COMPLEX_REAL (x),
 117                                           SCM_REAL_VALUE (y))
 118                              && SCM_COMPLEX_IMAG (x) == 0.0);
 119         }
 120       return SCM_BOOL_F;
 121     }
 122   if (SCM_NUMP (x))
 123     {
 124       if (SCM_BIGP (x)) {
 125         return SCM_BOOL (0 == scm_bigcomp (x, y));
 126       } else if (SCM_SLOPPY_REALP (x)) {
 127         return SCM_BOOL (real_eqv (SCM_REAL_VALUE (x), SCM_REAL_VALUE (y)));
 128       } else { /* complex */
 129         return SCM_BOOL (real_eqv (SCM_COMPLEX_REAL (x),
 130                                    SCM_COMPLEX_REAL (y))
 131                          && real_eqv (SCM_COMPLEX_IMAG (x),
 132                                       SCM_COMPLEX_IMAG (y)));
 133       }
 134     }
 135   return SCM_BOOL_F;
 136 }
 137 #undef FUNC_NAME
 138
 139
 140 SCM_PRIMITIVE_GENERIC_1 (scm_equal_p, "equal?", scm_tc7_rpsubr,
 141                          (SCM x, SCM y),
 142  "Return @code{#t} iff @var{x} and @var{y} are recursively @code{eqv?} equivalent.\n"
 143  "@code{equal?} recursively compares the contents of pairs,\n"
 144  "vectors, and strings, applying @code{eqv?} on other objects such as\n"
 145  "numbers and symbols.  A rule of thumb is that objects are generally\n"
 146  "@code{equal?}  if they print the same.  @code{equal?} may fail to\n"
 147  "terminate if its arguments are circular data structures.")
 148 #define FUNC_NAME s_scm_equal_p
 149 {
 150   SCM_CHECK_STACK;
 151  tailrecurse:
 152   SCM_TICK;
 153   if (SCM_EQ_P (x, y))
 154     return SCM_BOOL_T;
 155   if (SCM_IMP (x))
 156     return SCM_BOOL_F;
 157   if (SCM_IMP (y))
 158     return SCM_BOOL_F;
 159   if (SCM_CONSP (x) && SCM_CONSP (y))
 160     {
 161       if (SCM_FALSEP (scm_equal_p (SCM_CAR (x), SCM_CAR (y))))
 162         return SCM_BOOL_F;
 163       x = SCM_CDR(x);
 164       y = SCM_CDR(y);
 165       goto tailrecurse;
 166     }
 167   if (SCM_TYP7S (x) == scm_tc7_string && SCM_TYP7S (y) == scm_tc7_string)
 168     return scm_string_equal_p (x, y);
 169   /* This ensures that types and scm_length are the same.  */
 170   if (SCM_CELL_TYPE (x) != SCM_CELL_TYPE (y))
 171     {
 172       /* treat mixes of real and complex types specially */
 173       if (SCM_SLOPPY_INEXACTP (x))
 174         {
 175           if (SCM_SLOPPY_REALP (x))
 176             return SCM_BOOL (SCM_SLOPPY_COMPLEXP (y)
 177                              && SCM_REAL_VALUE (x) == SCM_COMPLEX_REAL (y)
 178                              && 0.0 == SCM_COMPLEX_IMAG (y));
 179           else
 180             return SCM_BOOL (SCM_SLOPPY_REALP (y)
 181                              && SCM_COMPLEX_REAL (x) == SCM_REAL_VALUE (y)
 182                              && SCM_COMPLEX_IMAG (x) == 0.0);
 183         }
 184       return SCM_BOOL_F;
 185     }
 186   switch (SCM_TYP7 (x))
 187     {
 188     default:
 189       break;
 190     case scm_tc7_vector:
 191     case scm_tc7_wvect:
 192       return scm_vector_equal_p (x, y);
 193     case scm_tc7_smob:
 194       {
 195         int i = SCM_SMOBNUM (x);
 196         if (!(i < scm_numsmob))
 197           return SCM_BOOL_F;
 198         if (scm_smobs[i].equalp)
 199           return (scm_smobs[i].equalp) (x, y);
 200         else
 201           break;
 202       }
 203 #ifdef SCM_HAVE_ARRAYS
 204     case scm_tc7_bvect: case scm_tc7_uvect: case scm_tc7_ivect:
 205     case scm_tc7_fvect: case scm_tc7_cvect: case scm_tc7_dvect:
 206     case scm_tc7_svect:
 207 #if SCM_SIZEOF_LONG_LONG != 0
 208     case scm_tc7_llvect:
 209 #endif
 210     case scm_tc7_byvect:
 211       if (scm_tc16_array && scm_smobs[SCM_TC2SMOBNUM (scm_tc16_array)].equalp)
 212         return scm_array_equal_p (x, y);
 213 #endif
 214     }
 215   if (SCM_UNPACK (g_scm_equal_p))
 216     return scm_call_generic_2 (g_scm_equal_p, x, y);
 217   else
 218     return SCM_BOOL_F;
 219 }
 220 #undef FUNC_NAME
 221
 222
 223 \f
 224
 225
 226
 227 void
 228 scm_init_eq ()
 229 {
 230 #include "libguile/eq.x"
 231 }
 232
 233
 234 /*
 235   Local Variables:
 236   c-file-style: "gnu"
 237   End:
 238 */