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/* Copyright (C) 1995,1996,2000,2001, 2004, 2005, 2006, 2008 Free Software Foundation, Inc.
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public License
* as published by the Free Software Foundation; either version 3 of
* the License, or (at your option) any later version.
*
* This library is distributed in the hope that it will be useful, but
* WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
* 02110-1301 USA
*/
#ifdef HAVE_CONFIG_H
# include <config.h>
#endif
#include "libguile/_scm.h"
#include "libguile/validate.h"
#include "libguile/pairs.h"
/* {Pairs}
*/
#if (SCM_DEBUG_PAIR_ACCESSES == 1)
#include "libguile/ports.h"
#include "libguile/strings.h"
void scm_error_pair_access (SCM non_pair)
{
static unsigned int running = 0;
SCM message = scm_from_locale_string ("Non-pair accessed with SCM_C[AD]R: `~S'\n");
if (!running)
{
running = 1;
scm_simple_format (scm_current_error_port (),
message, scm_list_1 (non_pair));
abort ();
}
}
#endif
SCM_DEFINE (scm_cons, "cons", 2, 0, 0,
(SCM x, SCM y),
"Return a newly allocated pair whose car is @var{x} and whose\n"
"cdr is @var{y}. The pair is guaranteed to be different (in the\n"
"sense of @code{eq?}) from every previously existing object.")
#define FUNC_NAME s_scm_cons
{
return scm_cell (SCM_UNPACK (x), SCM_UNPACK (y));
}
#undef FUNC_NAME
SCM
scm_cons2 (SCM w, SCM x, SCM y)
{
return scm_cons (w, scm_cons (x, y));
}
SCM_DEFINE (scm_pair_p, "pair?", 1, 0, 0,
(SCM x),
"Return @code{#t} if @var{x} is a pair; otherwise return\n"
"@code{#f}.")
#define FUNC_NAME s_scm_pair_p
{
return scm_from_bool (scm_is_pair (x));
}
#undef FUNC_NAME
SCM
scm_car (SCM pair)
{
if (!scm_is_pair (pair))
scm_wrong_type_arg_msg (NULL, 0, pair, "pair");
return SCM_CAR (pair);
}
SCM
scm_cdr (SCM pair)
{
if (!scm_is_pair (pair))
scm_wrong_type_arg_msg (NULL, 0, pair, "pair");
return SCM_CDR (pair);
}
SCM
scm_i_chase_pairs (SCM tree, scm_t_uint32 pattern)
{
do
{
if (!scm_is_pair (tree))
scm_wrong_type_arg_msg (NULL, 0, tree, "pair");
tree = (pattern & 1) ? SCM_CAR (tree) : SCM_CDR (tree);
pattern >>= 2;
}
while (pattern);
return tree;
}
SCM_DEFINE (scm_set_car_x, "set-car!", 2, 0, 0,
(SCM pair, SCM value),
"Stores @var{value} in the car field of @var{pair}. The value returned\n"
"by @code{set-car!} is unspecified.")
#define FUNC_NAME s_scm_set_car_x
{
SCM_VALIDATE_CONS (1, pair);
SCM_SETCAR (pair, value);
return SCM_UNSPECIFIED;
}
#undef FUNC_NAME
SCM_DEFINE (scm_set_cdr_x, "set-cdr!", 2, 0, 0,
(SCM pair, SCM value),
"Stores @var{value} in the cdr field of @var{pair}. The value returned\n"
"by @code{set-cdr!} is unspecified.")
#define FUNC_NAME s_scm_set_cdr_x
{
SCM_VALIDATE_CONS (1, pair);
SCM_SETCDR (pair, value);
return SCM_UNSPECIFIED;
}
#undef FUNC_NAME
/* Every cxr-pattern is made up of pairs of bits, starting with the two least
* significant bits. If in a pair of bits the least significant of the two
* bits is 0, this means CDR, otherwise CAR. The most significant bits of the
* two bits is only needed to indicate when cxr-ing is ready. This is the
* case, when all remaining pairs of bits equal 00. */
typedef struct {
const char *name;
unsigned char pattern;
} t_cxr;
static const t_cxr cxrs[] =
{
{"cdr", 0x02}, /* 00000010 */
{"car", 0x03}, /* 00000011 */
{"cddr", 0x0a}, /* 00001010 */
{"cdar", 0x0b}, /* 00001011 */
{"cadr", 0x0e}, /* 00001110 */
{"caar", 0x0f}, /* 00001111 */
{"cdddr", 0x2a}, /* 00101010 */
{"cddar", 0x2b}, /* 00101011 */
{"cdadr", 0x2e}, /* 00101110 */
{"cdaar", 0x2f}, /* 00101111 */
{"caddr", 0x3a}, /* 00111010 */
{"cadar", 0x3b}, /* 00111011 */
{"caadr", 0x3e}, /* 00111110 */
{"caaar", 0x3f}, /* 00111111 */
{"cddddr", 0xaa}, /* 10101010 */
{"cdddar", 0xab}, /* 10101011 */
{"cddadr", 0xae}, /* 10101110 */
{"cddaar", 0xaf}, /* 10101111 */
{"cdaddr", 0xba}, /* 10111010 */
{"cdadar", 0xbb}, /* 10111011 */
{"cdaadr", 0xbe}, /* 10111110 */
{"cdaaar", 0xbf}, /* 10111111 */
{"cadddr", 0xea}, /* 11101010 */
{"caddar", 0xeb}, /* 11101011 */
{"cadadr", 0xee}, /* 11101110 */
{"cadaar", 0xef}, /* 11101111 */
{"caaddr", 0xfa}, /* 11111010 */
{"caadar", 0xfb}, /* 11111011 */
{"caaadr", 0xfe}, /* 11111110 */
{"caaaar", 0xff}, /* 11111111 */
{0, 0}
};
void
scm_init_pairs ()
{
unsigned int subnr = 0;
for (subnr = 0; cxrs[subnr].name; subnr++)
{
SCM (*pattern) () = (SCM (*) ()) (scm_t_bits) cxrs[subnr].pattern;
scm_c_define_subr (cxrs[subnr].name, scm_tc7_cxr, pattern);
}
#include "libguile/pairs.x"
}
/*
Local Variables:
c-file-style: "gnu"
End:
*/
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