1 /* Copyright (C) 1995,1996,2000,2001, 2004 Free Software Foundation, Inc.
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.
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.
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
21 #include "libguile/_scm.h"
22 #include "libguile/validate.h"
24 #include "libguile/pairs.h"
31 #if (SCM_DEBUG_PAIR_ACCESSES == 1)
33 #include "libguile/ports.h"
34 #include "libguile/strings.h"
36 void scm_error_pair_access (SCM non_pair
)
38 static unsigned int running
= 0;
39 SCM message
= scm_makfrom0str ("Non-pair accessed with SCM_C[AD]R: `~S´\n");
44 scm_simple_format (scm_current_error_port (),
45 message
, scm_list_1 (non_pair
));
52 SCM_DEFINE (scm_cons
, "cons", 2, 0, 0,
54 "Return a newly allocated pair whose car is @var{x} and whose\n"
55 "cdr is @var{y}. The pair is guaranteed to be different (in the\n"
56 "sense of @code{eq?}) from every previously existing object.")
57 #define FUNC_NAME s_scm_cons
59 return scm_cell (SCM_UNPACK (x
), SCM_UNPACK (y
));
65 scm_cons2 (SCM w
, SCM x
, SCM y
)
67 return scm_cons (w
, scm_cons (x
, y
));
71 SCM_DEFINE (scm_pair_p
, "pair?", 1, 0, 0,
73 "Return @code{#t} if @var{x} is a pair; otherwise return\n"
75 #define FUNC_NAME s_scm_pair_p
77 return scm_from_bool (scm_is_pair (x
));
84 return SCM_I_CONSP (x
);
90 if (!scm_is_pair (pair
))
91 scm_wrong_type_arg_msg (NULL
, 0, pair
, "pair");
92 return SCM_CAR (pair
);
98 if (!scm_is_pair (pair
))
99 scm_wrong_type_arg_msg (NULL
, 0, pair
, "pair");
100 return SCM_CDR (pair
);
104 scm_i_chase_pairs (SCM tree
, scm_t_uint32 pattern
)
108 if (!scm_is_pair (tree
))
109 scm_wrong_type_arg_msg (NULL
, 0, tree
, "pair");
110 tree
= (pattern
& 1) ? SCM_CAR (tree
) : SCM_CDR (tree
);
117 SCM_DEFINE (scm_set_car_x
, "set-car!", 2, 0, 0,
118 (SCM pair
, SCM value
),
119 "Stores @var{value} in the car field of @var{pair}. The value returned\n"
120 "by @code{set-car!} is unspecified.")
121 #define FUNC_NAME s_scm_set_car_x
123 SCM_VALIDATE_CONS (1, pair
);
124 SCM_SETCAR (pair
, value
);
125 return SCM_UNSPECIFIED
;
130 SCM_DEFINE (scm_set_cdr_x
, "set-cdr!", 2, 0, 0,
131 (SCM pair
, SCM value
),
132 "Stores @var{value} in the cdr field of @var{pair}. The value returned\n"
133 "by @code{set-cdr!} is unspecified.")
134 #define FUNC_NAME s_scm_set_cdr_x
136 SCM_VALIDATE_CONS (1, pair
);
137 SCM_SETCDR (pair
, value
);
138 return SCM_UNSPECIFIED
;
144 /* Every cxr-pattern is made up of pairs of bits, starting with the two least
145 * significant bits. If in a pair of bits the least significant of the two
146 * bits is 0, this means CDR, otherwise CAR. The most significant bits of the
147 * two bits is only needed to indicate when cxr-ing is ready. This is the
148 * case, when all remaining pairs of bits equal 00. */
152 unsigned char pattern
;
155 static const t_cxr cxrs
[] =
157 {"cdr", 0x02}, /* 00000010 */
158 {"car", 0x03}, /* 00000011 */
159 {"cddr", 0x0a}, /* 00001010 */
160 {"cdar", 0x0b}, /* 00001011 */
161 {"cadr", 0x0e}, /* 00001110 */
162 {"caar", 0x0f}, /* 00001111 */
163 {"cdddr", 0x2a}, /* 00101010 */
164 {"cddar", 0x2b}, /* 00101011 */
165 {"cdadr", 0x2e}, /* 00101110 */
166 {"cdaar", 0x2f}, /* 00101111 */
167 {"caddr", 0x3a}, /* 00111010 */
168 {"cadar", 0x3b}, /* 00111011 */
169 {"caadr", 0x3e}, /* 00111110 */
170 {"caaar", 0x3f}, /* 00111111 */
171 {"cddddr", 0xaa}, /* 10101010 */
172 {"cdddar", 0xab}, /* 10101011 */
173 {"cddadr", 0xae}, /* 10101110 */
174 {"cddaar", 0xaf}, /* 10101111 */
175 {"cdaddr", 0xba}, /* 10111010 */
176 {"cdadar", 0xbb}, /* 10111011 */
177 {"cdaadr", 0xbe}, /* 10111110 */
178 {"cdaaar", 0xbf}, /* 10111111 */
179 {"cadddr", 0xea}, /* 11101010 */
180 {"caddar", 0xeb}, /* 11101011 */
181 {"cadadr", 0xee}, /* 11101110 */
182 {"cadaar", 0xef}, /* 11101111 */
183 {"caaddr", 0xfa}, /* 11111010 */
184 {"caadar", 0xfb}, /* 11111011 */
185 {"caaadr", 0xfe}, /* 11111110 */
186 {"caaaar", 0xff}, /* 11111111 */
195 unsigned int subnr
= 0;
197 for (subnr
= 0; cxrs
[subnr
].name
; subnr
++)
199 SCM (*pattern
) () = (SCM (*) ()) (scm_t_bits
) cxrs
[subnr
].pattern
;
200 scm_c_define_subr (cxrs
[subnr
].name
, scm_tc7_cxr
, pattern
);
203 #include "libguile/pairs.x"