libguile/pairs.c

   1 /* Copyright (C) 1995,1996,2000,2001 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 /* Software engineering face-lift by Greg J. Badros, 11-Dec-1999,
  43    gjb@cs.washington.edu, http://www.cs.washington.edu/homes/gjb */
  44
  45 \f
  46
  47 #include "libguile/_scm.h"
  48 #include "libguile/validate.h"
  49
  50 #include "libguile/pairs.h"
  51
  52 \f
  53
  54 /* {Pairs}
  55  */
  56
  57 #if (SCM_DEBUG_PAIR_ACCESSES == 1)
  58
  59 #include "libguile/ports.h"
  60 #include "libguile/strings.h"
  61
  62 void scm_error_pair_access (SCM non_pair)
  63 {
  64   static unsigned int running = 0;
  65   SCM message = scm_makfrom0str ("Non-pair accessed with SCM_C[AD]R: `~S´\n");
  66
  67   if (!running)
  68     {
  69       running = 1;
  70       scm_simple_format (scm_current_error_port (),
  71                          message, scm_list_1 (non_pair));
  72       abort ();
  73     }
  74 }
  75
  76 #endif
  77
  78 SCM_DEFINE (scm_cons, "cons", 2, 0, 0,
  79             (SCM x, SCM y),
  80             "Return a newly allocated pair whose car is @var{x} and whose\n"
  81             "cdr is @var{y}.  The pair is guaranteed to be different (in the\n"
  82             "sense of @code{eq?}) from every previously existing object.")
  83 #define FUNC_NAME s_scm_cons
  84 {
  85   SCM z;
  86   SCM_NEWCELL (z);
  87   SCM_SET_CELL_OBJECT_0 (z, x);
  88   SCM_SET_CELL_OBJECT_1 (z, y);
  89   return z;
  90 }
  91 #undef FUNC_NAME
  92
  93
  94 SCM
  95 scm_cons2 (SCM w, SCM x, SCM y)
  96 {
  97   SCM z1;
  98   SCM z2;
  99
 100   SCM_NEWCELL (z1);
 101   SCM_SET_CELL_OBJECT_0 (z1, x);
 102   SCM_SET_CELL_OBJECT_1 (z1, y);
 103
 104   SCM_NEWCELL (z2);
 105   SCM_SET_CELL_OBJECT_0 (z2, w);
 106   SCM_SET_CELL_OBJECT_1 (z2, z1);
 107
 108   return z2;
 109 }
 110
 111
 112 SCM_DEFINE (scm_pair_p, "pair?", 1, 0, 0,
 113             (SCM x),
 114             "Return @code{#t} if @var{x} is a pair; otherwise return\n"
 115             "@code{#f}.")
 116 #define FUNC_NAME s_scm_pair_p
 117 {
 118   return SCM_BOOL (SCM_CONSP (x));
 119 }
 120 #undef FUNC_NAME
 121
 122
 123 SCM_DEFINE (scm_set_car_x, "set-car!", 2, 0, 0,
 124             (SCM pair, SCM value),
 125             "Stores @var{value} in the car field of @var{pair}.  The value returned\n"
 126             "by @code{set-car!} is unspecified.")
 127 #define FUNC_NAME s_scm_set_car_x
 128 {
 129   SCM_VALIDATE_CONS (1, pair);
 130   SCM_SETCAR (pair, value);
 131   return SCM_UNSPECIFIED;
 132 }
 133 #undef FUNC_NAME
 134
 135
 136 SCM_DEFINE (scm_set_cdr_x, "set-cdr!", 2, 0, 0,
 137             (SCM pair, SCM value),
 138             "Stores @var{value} in the cdr field of @var{pair}.  The value returned\n"
 139             "by @code{set-cdr!} is unspecified.")
 140 #define FUNC_NAME s_scm_set_cdr_x
 141 {
 142   SCM_VALIDATE_CONS (1, pair);
 143   SCM_SETCDR (pair, value);
 144   return SCM_UNSPECIFIED;
 145 }
 146 #undef FUNC_NAME
 147
 148 \f
 149
 150 static const char * cxrs[] =
 151 {
 152   "car",
 153   "cdr",
 154   "caar",
 155   "cadr",
 156   "cdar",
 157   "cddr",
 158   "caaar",
 159   "caadr",
 160   "cadar",
 161   "caddr",
 162   "cdaar",
 163   "cdadr",
 164   "cddar",
 165   "cdddr",
 166   "caaaar",
 167   "caaadr",
 168   "caadar",
 169   "caaddr",
 170   "cadaar",
 171   "cadadr",
 172   "caddar",
 173   "cadddr",
 174   "cdaaar",
 175   "cdaadr",
 176   "cdadar",
 177   "cdaddr",
 178   "cddaar",
 179   "cddadr",
 180   "cdddar",
 181   "cddddr",
 182   0
 183 };
 184
 185 \f
 186
 187 void
 188 scm_init_pairs ()
 189 {
 190   unsigned int subnr = 0;
 191
 192   for (subnr = 0; cxrs [subnr]; subnr++)
 193     scm_c_define_subr (cxrs [subnr], scm_tc7_cxr, NULL);
 194
 195 #ifndef SCM_MAGIC_SNARFER
 196 #include "libguile/pairs.x"
 197 #endif
 198 }
 199
 200
 201 /*
 202   Local Variables:
 203   c-file-style: "gnu"
 204   End:
 205 */