libguile/pairs.c

   1 /*      Copyright (C) 1995,1996 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 #include <stdio.h>
  47 #include "libguile/_scm.h"
  48
  49
  50 #include "libguile/validate.h"
  51
  52 \f
  53
  54 /* {Pairs}
  55  */
  56
  57 SCM_DEFINE (scm_cons, "cons", 2, 0, 0,
  58            (SCM x, SCM y),
  59             "Returns a newly allocated pair whose car is @var{x} and whose cdr is\n"
  60             "@var{y}.  The pair is guaranteed to be different (in the sense of\n"
  61             "@code{eqv?}) from every previously existing object.")
  62 #define FUNC_NAME s_scm_cons
  63 {
  64   register SCM z;
  65   SCM_NEWCELL (z);
  66   SCM_SETCAR (z, x);
  67   SCM_SETCDR (z, y);
  68   return z;
  69 }
  70 #undef FUNC_NAME
  71
  72
  73 SCM
  74 scm_cons2 (SCM w, SCM x, SCM y)
  75 {
  76   register SCM z;
  77   SCM_NEWCELL (z);
  78   SCM_SETCAR (z, x);
  79   SCM_SETCDR (z, y);
  80   x = z;
  81   SCM_NEWCELL (z);
  82   SCM_SETCAR (z, w);
  83   SCM_SETCDR (z, x);
  84   return z;
  85 }
  86
  87
  88 SCM_DEFINE (scm_pair_p, "pair?", 1, 0, 0,
  89             (SCM x),
  90             "Returns @code{#t} if @var{x} is a pair; otherwise returns @code{#f}.")
  91 #define FUNC_NAME s_scm_pair_p
  92 {
  93   if (SCM_IMP (x))
  94     return SCM_BOOL_F;
  95   return SCM_BOOL(SCM_CONSP (x));
  96 }
  97 #undef FUNC_NAME
  98
  99 SCM_DEFINE (scm_set_car_x, "set-car!", 2, 0, 0,
 100             (SCM pair, SCM value),
 101             "Stores @var{value} in the car field of @var{pair}.  The value returned\n"
 102             "by @code{set-car!} is unspecified.")
 103 #define FUNC_NAME s_scm_set_car_x
 104 {
 105   SCM_VALIDATE_CONS (1,pair);
 106   SCM_SETCAR (pair, value);
 107   return SCM_UNSPECIFIED;
 108 }
 109 #undef FUNC_NAME
 110
 111 SCM_DEFINE (scm_set_cdr_x, "set-cdr!", 2, 0, 0,
 112             (SCM pair, SCM value),
 113             "Stores @var{value} in the cdr field of @var{pair}.  The value returned\n"
 114             "by @code{set-cdr!} is unspecified.")
 115 #define FUNC_NAME s_scm_set_cdr_x
 116 {
 117   SCM_VALIDATE_CONS (1,pair);
 118   SCM_SETCDR (pair, value);
 119   return SCM_UNSPECIFIED;
 120 }
 121 #undef FUNC_NAME
 122
 123
 124 \f
 125
 126 static const char * cxrs[] =
 127 {
 128   "car",
 129   "cdr",
 130   "caar",
 131   "cadr",
 132   "cdar",
 133   "cddr",
 134   "caaar",
 135   "caadr",
 136   "cadar",
 137   "caddr",
 138   "cdaar",
 139   "cdadr",
 140   "cddar",
 141   "cdddr",
 142   "caaaar",
 143   "caaadr",
 144   "caadar",
 145   "caaddr",
 146   "cadaar",
 147   "cadadr",
 148   "caddar",
 149   "cadddr",
 150   "cdaaar",
 151   "cdaadr",
 152   "cdadar",
 153   "cdaddr",
 154   "cddaar",
 155   "cddadr",
 156   "cdddar",
 157   "cddddr",
 158   0
 159 };
 160
 161 \f
 162
 163 void
 164 scm_init_pairs ()
 165 {
 166   unsigned int subnr = 0;
 167
 168   for (subnr = 0; cxrs [subnr]; subnr++)
 169     scm_make_subr(cxrs [subnr], scm_tc7_cxr, NULL);
 170
 171 #include "libguile/pairs.x"
 172 }
 173
 174
 175 /*
 176   Local Variables:
 177   c-file-style: "gnu"
 178   End:
 179 */