libguile/eq.c

   1 /* Copyright (C) 1995,1996,1997,1998,2000,2001, 2003 Free Software Foundation, Inc.
   2  *
   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.
   7  *
   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.
  12  *
  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
  15  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
  16  */
  17
  18 \f
  19 #if HAVE_CONFIG_H
  20 #  include <config.h>
  21 #endif
  22
  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"
  32
  33 #include "libguile/validate.h"
  34 #include "libguile/eq.h"
  35 \f
  36
  37 #ifdef HAVE_STRING_H
  38 #include <string.h>
  39 #endif
  40 \f
  41
  42 SCM_DEFINE1 (scm_eq_p, "eq?", scm_tc7_rpsubr,
  43              (SCM x, SCM y),
  44              "Return @code{#t} iff @var{x} references the same object as @var{y}.\n"
  45              "@code{eq?} is similar to @code{eqv?} except that in some cases it is\n"
  46              "capable of discerning distinctions finer than those detectable by\n"
  47              "@code{eqv?}.")
  48 #define FUNC_NAME s_scm_eq_p
  49 {
  50   return SCM_BOOL (SCM_EQ_P (x, y));
  51 }
  52 #undef FUNC_NAME
  53
  54 /* We compare doubles in a special way for 'eqv?' to be able to
  55    distinguish plus and minus zero and to identify NaNs.
  56 */
  57
  58 static int
  59 real_eqv (double x, double y)
  60 {
  61   return !memcmp (&x, &y, sizeof(double));
  62 }
  63
  64 SCM_DEFINE1 (scm_eqv_p, "eqv?", scm_tc7_rpsubr,
  65              (SCM x, SCM y),
  66              "The @code{eqv?} procedure defines a useful equivalence relation on objects.\n"
  67              "Briefly, it returns @code{#t} if @var{x} and @var{y} should normally be\n"
  68              "regarded as the same object.  This relation is left slightly open to\n"
  69              "interpretation, but works for comparing immediate integers, characters,\n"
  70              "and inexact numbers.")
  71 #define FUNC_NAME s_scm_eqv_p
  72 {
  73   if (SCM_EQ_P (x, y))
  74     return SCM_BOOL_T;
  75   if (SCM_IMP (x))
  76     return SCM_BOOL_F;
  77   if (SCM_IMP (y))
  78     return SCM_BOOL_F;
  79   /* this ensures that types and scm_length are the same. */
  80   if (SCM_CELL_TYPE (x) != SCM_CELL_TYPE (y))
  81     {
  82       /* treat mixes of real and complex types specially */
  83       if (SCM_SLOPPY_INEXACTP (x))
  84         {
  85           if (SCM_SLOPPY_REALP (x))
  86             return SCM_BOOL (SCM_SLOPPY_COMPLEXP (y)
  87                              && real_eqv (SCM_REAL_VALUE (x),
  88                                           SCM_COMPLEX_REAL (y))
  89                              && 0.0 == SCM_COMPLEX_IMAG (y));
  90           else
  91             return SCM_BOOL (SCM_SLOPPY_REALP (y)
  92                              && real_eqv (SCM_COMPLEX_REAL (x),
  93                                           SCM_REAL_VALUE (y))
  94                              && SCM_COMPLEX_IMAG (x) == 0.0);
  95         }
  96       return SCM_BOOL_F;
  97     }
  98   if (SCM_NUMP (x))
  99     {
 100       if (SCM_BIGP (x)) {
 101         return SCM_BOOL (0 == scm_i_bigcmp (x, y));
 102       } else if (SCM_SLOPPY_REALP (x)) {
 103         return SCM_BOOL (real_eqv (SCM_REAL_VALUE (x), SCM_REAL_VALUE (y)));
 104       } else { /* complex */
 105         return SCM_BOOL (real_eqv (SCM_COMPLEX_REAL (x),
 106                                    SCM_COMPLEX_REAL (y))
 107                          && real_eqv (SCM_COMPLEX_IMAG (x),
 108                                       SCM_COMPLEX_IMAG (y)));
 109       }
 110     }
 111   return SCM_BOOL_F;
 112 }
 113 #undef FUNC_NAME
 114
 115
 116 SCM_PRIMITIVE_GENERIC_1 (scm_equal_p, "equal?", scm_tc7_rpsubr,
 117                          (SCM x, SCM y),
 118  "Return @code{#t} iff @var{x} and @var{y} are recursively @code{eqv?} equivalent.\n"
 119  "@code{equal?} recursively compares the contents of pairs,\n"
 120  "vectors, and strings, applying @code{eqv?} on other objects such as\n"
 121  "numbers and symbols.  A rule of thumb is that objects are generally\n"
 122  "@code{equal?}  if they print the same.  @code{equal?} may fail to\n"
 123  "terminate if its arguments are circular data structures.")
 124 #define FUNC_NAME s_scm_equal_p
 125 {
 126   SCM_CHECK_STACK;
 127  tailrecurse:
 128   SCM_TICK;
 129   if (SCM_EQ_P (x, y))
 130     return SCM_BOOL_T;
 131   if (SCM_IMP (x))
 132     return SCM_BOOL_F;
 133   if (SCM_IMP (y))
 134     return SCM_BOOL_F;
 135   if (SCM_CONSP (x) && SCM_CONSP (y))
 136     {
 137       if (SCM_FALSEP (scm_equal_p (SCM_CAR (x), SCM_CAR (y))))
 138         return SCM_BOOL_F;
 139       x = SCM_CDR(x);
 140       y = SCM_CDR(y);
 141       goto tailrecurse;
 142     }
 143   if (SCM_TYP7S (x) == scm_tc7_string && SCM_TYP7S (y) == scm_tc7_string)
 144     return scm_string_equal_p (x, y);
 145   /* This ensures that types and scm_length are the same.  */
 146   if (SCM_CELL_TYPE (x) != SCM_CELL_TYPE (y))
 147     {
 148       /* treat mixes of real and complex types specially */
 149       if (SCM_SLOPPY_INEXACTP (x))
 150         {
 151           if (SCM_SLOPPY_REALP (x))
 152             return SCM_BOOL (SCM_SLOPPY_COMPLEXP (y)
 153                              && SCM_REAL_VALUE (x) == SCM_COMPLEX_REAL (y)
 154                              && 0.0 == SCM_COMPLEX_IMAG (y));
 155           else
 156             return SCM_BOOL (SCM_SLOPPY_REALP (y)
 157                              && SCM_COMPLEX_REAL (x) == SCM_REAL_VALUE (y)
 158                              && SCM_COMPLEX_IMAG (x) == 0.0);
 159         }
 160       return SCM_BOOL_F;
 161     }
 162   switch (SCM_TYP7 (x))
 163     {
 164     default:
 165       break;
 166     case scm_tc7_vector:
 167     case scm_tc7_wvect:
 168       return scm_vector_equal_p (x, y);
 169     case scm_tc7_smob:
 170       {
 171         int i = SCM_SMOBNUM (x);
 172         if (!(i < scm_numsmob))
 173           return SCM_BOOL_F;
 174         if (scm_smobs[i].equalp)
 175           return (scm_smobs[i].equalp) (x, y);
 176         else
 177           break;
 178       }
 179 #if SCM_HAVE_ARRAYS
 180     case scm_tc7_bvect: case scm_tc7_uvect: case scm_tc7_ivect:
 181     case scm_tc7_fvect: case scm_tc7_cvect: case scm_tc7_dvect:
 182     case scm_tc7_svect:
 183 #if SCM_SIZEOF_LONG_LONG != 0
 184     case scm_tc7_llvect:
 185 #endif
 186     case scm_tc7_byvect:
 187       if (scm_tc16_array && scm_smobs[SCM_TC2SMOBNUM (scm_tc16_array)].equalp)
 188         return scm_array_equal_p (x, y);
 189 #endif
 190     }
 191   if (SCM_UNPACK (g_scm_equal_p))
 192     return scm_call_generic_2 (g_scm_equal_p, x, y);
 193   else
 194     return SCM_BOOL_F;
 195 }
 196 #undef FUNC_NAME
 197
 198
 199 \f
 200
 201
 202
 203 void
 204 scm_init_eq ()
 205 {
 206 #include "libguile/eq.x"
 207 }
 208
 209
 210 /*
 211   Local Variables:
 212   c-file-style: "gnu"
 213   End:
 214 */