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