libguile/alist.c

   1 /* Copyright (C) 1995, 96, 97, 98, 99, 2000, 2001, 2004, 2006, 2008 Free Software Foundation, Inc.
   2  *
   3  * This library is free software; you can redistribute it and/or
   4  * modify it under the terms of the GNU Lesser General Public License
   5  * as published by the Free Software Foundation; either version 3 of
   6  * the License, or (at your option) any later version.
   7  *
   8  * This library is distributed in the hope that it will be useful, but
   9  * 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.
  12  *
  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., 51 Franklin Street, Fifth Floor, Boston, MA
  16  * 02110-1301 USA
  17  */
  18
  19
  20 \f
  21 #ifdef HAVE_CONFIG_H
  22 # include <config.h>
  23 #endif
  24
  25 #include "libguile/_scm.h"
  26 #include "libguile/eq.h"
  27 #include "libguile/list.h"
  28 #include "libguile/lang.h"
  29
  30 #include "libguile/validate.h"
  31 #include "libguile/pairs.h"
  32 #include "libguile/alist.h"
  33
  34 \f
  35
  36 SCM_DEFINE (scm_acons, "acons", 3, 0, 0,
  37            (SCM key, SCM value, SCM alist),
  38             "Add a new key-value pair to @var{alist}.  A new pair is\n"
  39             "created whose car is @var{key} and whose cdr is @var{value}, and the\n"
  40             "pair is consed onto @var{alist}, and the new list is returned.  This\n"
  41             "function is @emph{not} destructive; @var{alist} is not modified.")
  42 #define FUNC_NAME s_scm_acons
  43 {
  44   return scm_cell (SCM_UNPACK (scm_cell (SCM_UNPACK (key),
  45                                          SCM_UNPACK (value))),
  46                    SCM_UNPACK (alist));
  47 }
  48 #undef FUNC_NAME
  49
  50 \f
  51
  52 SCM_DEFINE (scm_sloppy_assq, "sloppy-assq", 2, 0, 0,
  53             (SCM key, SCM alist),
  54             "Behaves like @code{assq} but does not do any error checking.\n"
  55             "Recommended only for use in Guile internals.")
  56 #define FUNC_NAME s_scm_sloppy_assq
  57 {
  58   for (; scm_is_pair (alist); alist = SCM_CDR (alist))
  59     {
  60       SCM tmp = SCM_CAR (alist);
  61       if (scm_is_pair (tmp) && scm_is_eq (SCM_CAR (tmp), key))
  62         return tmp;
  63     }
  64   return SCM_BOOL_F;
  65 }
  66 #undef FUNC_NAME
  67
  68
  69
  70 SCM_DEFINE (scm_sloppy_assv, "sloppy-assv", 2, 0, 0,
  71             (SCM key, SCM alist),
  72             "Behaves like @code{assv} but does not do any error checking.\n"
  73             "Recommended only for use in Guile internals.")
  74 #define FUNC_NAME s_scm_sloppy_assv
  75 {
  76   for (; scm_is_pair (alist); alist = SCM_CDR (alist))
  77     {
  78       SCM tmp = SCM_CAR (alist);
  79       if (scm_is_pair (tmp)
  80           && scm_is_true (scm_eqv_p (SCM_CAR (tmp), key)))
  81         return tmp;
  82     }
  83   return SCM_BOOL_F;
  84 }
  85 #undef FUNC_NAME
  86
  87
  88 SCM_DEFINE (scm_sloppy_assoc, "sloppy-assoc", 2, 0, 0,
  89             (SCM key, SCM alist),
  90             "Behaves like @code{assoc} but does not do any error checking.\n"
  91             "Recommended only for use in Guile internals.")
  92 #define FUNC_NAME s_scm_sloppy_assoc
  93 {
  94   for (; scm_is_pair (alist); alist = SCM_CDR (alist))
  95     {
  96       SCM tmp = SCM_CAR (alist);
  97       if (scm_is_pair (tmp)
  98           && scm_is_true (scm_equal_p (SCM_CAR (tmp), key)))
  99         return tmp;
 100     }
 101   return SCM_BOOL_F;
 102 }
 103 #undef FUNC_NAME
 104
 105
 106 \f
 107
 108 SCM_DEFINE (scm_assq, "assq", 2, 0, 0,
 109            (SCM key, SCM alist),
 110             "@deffnx {Scheme Procedure} assv key alist\n"
 111             "@deffnx {Scheme Procedure} assoc key alist\n"
 112             "Fetch the entry in @var{alist} that is associated with @var{key}.  To\n"
 113             "decide whether the argument @var{key} matches a particular entry in\n"
 114             "@var{alist}, @code{assq} compares keys with @code{eq?}, @code{assv}\n"
 115             "uses @code{eqv?} and @code{assoc} uses @code{equal?}.  If @var{key}\n"
 116             "cannot be found in @var{alist} (according to whichever equality\n"
 117             "predicate is in use), then return @code{#f}.  These functions\n"
 118             "return the entire alist entry found (i.e. both the key and the value).")
 119 #define FUNC_NAME s_scm_assq
 120 {
 121   SCM ls = alist;
 122   for(; scm_is_pair (ls); ls = SCM_CDR (ls))
 123     {
 124       SCM tmp = SCM_CAR (ls);
 125       SCM_ASSERT_TYPE (scm_is_pair (tmp), alist, SCM_ARG2, FUNC_NAME,
 126                        "association list");
 127       if (scm_is_eq (SCM_CAR (tmp), key))
 128         return tmp;
 129     }
 130   SCM_ASSERT_TYPE (SCM_NULL_OR_NIL_P (ls), alist, SCM_ARG2, FUNC_NAME,
 131                    "association list");
 132   return SCM_BOOL_F;
 133 }
 134 #undef FUNC_NAME
 135
 136
 137 SCM_DEFINE (scm_assv, "assv", 2, 0, 0,
 138            (SCM key, SCM alist),
 139             "Behaves like @code{assq} but uses @code{eqv?} for key comparison.")
 140 #define FUNC_NAME s_scm_assv
 141 {
 142   SCM ls = alist;
 143   for(; scm_is_pair (ls); ls = SCM_CDR (ls))
 144     {
 145       SCM tmp = SCM_CAR (ls);
 146       SCM_ASSERT_TYPE (scm_is_pair (tmp), alist, SCM_ARG2, FUNC_NAME,
 147                        "association list");
 148       if (scm_is_true (scm_eqv_p (SCM_CAR (tmp), key)))
 149         return tmp;
 150     }
 151   SCM_ASSERT_TYPE (SCM_NULL_OR_NIL_P (ls), alist, SCM_ARG2, FUNC_NAME,
 152                    "association list");
 153   return SCM_BOOL_F;
 154 }
 155 #undef FUNC_NAME
 156
 157
 158 SCM_DEFINE (scm_assoc, "assoc", 2, 0, 0,
 159            (SCM key, SCM alist),
 160             "Behaves like @code{assq} but uses @code{equal?} for key comparison.")
 161 #define FUNC_NAME s_scm_assoc
 162 {
 163   SCM ls = alist;
 164   for(; scm_is_pair (ls); ls = SCM_CDR (ls))
 165     {
 166       SCM tmp = SCM_CAR (ls);
 167       SCM_ASSERT_TYPE (scm_is_pair (tmp), alist, SCM_ARG2, FUNC_NAME,
 168                        "association list");
 169       if (scm_is_true (scm_equal_p (SCM_CAR (tmp), key)))
 170         return tmp;
 171     }
 172   SCM_ASSERT_TYPE (SCM_NULL_OR_NIL_P (ls), alist, SCM_ARG2, FUNC_NAME,
 173                    "association list");
 174   return SCM_BOOL_F;
 175 }
 176 #undef FUNC_NAME
 177
 178
 179 \f
 180
 181 /* Dirk:API2.0:: We should not return #f if the key was not found.  In the
 182  * current solution we can not distinguish between finding a (key . #f) pair
 183  * and not finding the key at all.
 184  *
 185  * Possible alternative solutions:
 186  * 1) Remove assq-ref from the API:  assq is sufficient.
 187  * 2) Signal an error (what error type?) if the key is not found.
 188  * 3) provide an additional 'default' parameter.
 189  * 3.1) The default parameter is mandatory.
 190  * 3.2) The default parameter is optional, but if no default is given and
 191  *      the key is not found, signal an error (what error type?).
 192  */
 193 SCM_DEFINE (scm_assq_ref, "assq-ref", 2, 0, 0,
 194             (SCM alist, SCM key),
 195             "@deffnx {Scheme Procedure} assv-ref alist key\n"
 196             "@deffnx {Scheme Procedure} assoc-ref alist key\n"
 197             "Like @code{assq}, @code{assv} and @code{assoc}, except that only the\n"
 198             "value associated with @var{key} in @var{alist} is returned.  These\n"
 199             "functions are equivalent to\n\n"
 200             "@lisp\n"
 201             "(let ((ent (@var{associator} @var{key} @var{alist})))\n"
 202             "  (and ent (cdr ent)))\n"
 203             "@end lisp\n\n"
 204             "where @var{associator} is one of @code{assq}, @code{assv} or @code{assoc}.")
 205 #define FUNC_NAME s_scm_assq_ref
 206 {
 207   SCM handle;
 208
 209   handle = scm_sloppy_assq (key, alist);
 210   if (scm_is_pair (handle))
 211     {
 212       return SCM_CDR (handle);
 213     }
 214   return SCM_BOOL_F;
 215 }
 216 #undef FUNC_NAME
 217
 218
 219 SCM_DEFINE (scm_assv_ref, "assv-ref", 2, 0, 0,
 220             (SCM alist, SCM key),
 221             "Behaves like @code{assq-ref} but uses @code{eqv?} for key comparison.")
 222 #define FUNC_NAME s_scm_assv_ref
 223 {
 224   SCM handle;
 225
 226   handle = scm_sloppy_assv (key, alist);
 227   if (scm_is_pair (handle))
 228     {
 229       return SCM_CDR (handle);
 230     }
 231   return SCM_BOOL_F;
 232 }
 233 #undef FUNC_NAME
 234
 235
 236 SCM_DEFINE (scm_assoc_ref, "assoc-ref", 2, 0, 0,
 237             (SCM alist, SCM key),
 238             "Behaves like @code{assq-ref} but uses @code{equal?} for key comparison.")
 239 #define FUNC_NAME s_scm_assoc_ref
 240 {
 241   SCM handle;
 242
 243   handle = scm_sloppy_assoc (key, alist);
 244   if (scm_is_pair (handle))
 245     {
 246       return SCM_CDR (handle);
 247     }
 248   return SCM_BOOL_F;
 249 }
 250 #undef FUNC_NAME
 251
 252
 253
 254 \f
 255
 256
 257 SCM_DEFINE (scm_assq_set_x, "assq-set!", 3, 0, 0,
 258             (SCM alist, SCM key, SCM val),
 259             "@deffnx {Scheme Procedure} assv-set! alist key value\n"
 260             "@deffnx {Scheme Procedure} assoc-set! alist key value\n"
 261             "Reassociate @var{key} in @var{alist} with @var{value}: find any existing\n"
 262             "@var{alist} entry for @var{key} and associate it with the new\n"
 263             "@var{value}.  If @var{alist} does not contain an entry for @var{key},\n"
 264             "add a new one.  Return the (possibly new) alist.\n\n"
 265             "These functions do not attempt to verify the structure of @var{alist},\n"
 266             "and so may cause unusual results if passed an object that is not an\n"
 267             "association list.")
 268 #define FUNC_NAME s_scm_assq_set_x
 269 {
 270   SCM handle;
 271
 272   handle = scm_sloppy_assq (key, alist);
 273   if (scm_is_pair (handle))
 274     {
 275       SCM_SETCDR (handle, val);
 276       return alist;
 277     }
 278   else
 279     return scm_acons (key, val, alist);
 280 }
 281 #undef FUNC_NAME
 282
 283 SCM_DEFINE (scm_assv_set_x, "assv-set!", 3, 0, 0,
 284             (SCM alist, SCM key, SCM val),
 285             "Behaves like @code{assq-set!} but uses @code{eqv?} for key comparison.")
 286 #define FUNC_NAME s_scm_assv_set_x
 287 {
 288   SCM handle;
 289
 290   handle = scm_sloppy_assv (key, alist);
 291   if (scm_is_pair (handle))
 292     {
 293       SCM_SETCDR (handle, val);
 294       return alist;
 295     }
 296   else
 297     return scm_acons (key, val, alist);
 298 }
 299 #undef FUNC_NAME
 300
 301 SCM_DEFINE (scm_assoc_set_x, "assoc-set!", 3, 0, 0,
 302             (SCM alist, SCM key, SCM val),
 303             "Behaves like @code{assq-set!} but uses @code{equal?} for key comparison.")
 304 #define FUNC_NAME s_scm_assoc_set_x
 305 {
 306   SCM handle;
 307
 308   handle = scm_sloppy_assoc (key, alist);
 309   if (scm_is_pair (handle))
 310     {
 311       SCM_SETCDR (handle, val);
 312       return alist;
 313     }
 314   else
 315     return scm_acons (key, val, alist);
 316 }
 317 #undef FUNC_NAME
 318
 319
 320 \f
 321
 322 SCM_DEFINE (scm_assq_remove_x, "assq-remove!", 2, 0, 0,
 323             (SCM alist, SCM key),
 324             "@deffnx {Scheme Procedure} assv-remove! alist key\n"
 325             "@deffnx {Scheme Procedure} assoc-remove! alist key\n"
 326             "Delete the first entry in @var{alist} associated with @var{key}, and return\n"
 327             "the resulting alist.")
 328 #define FUNC_NAME s_scm_assq_remove_x
 329 {
 330   SCM handle;
 331
 332   handle = scm_sloppy_assq (key, alist);
 333   if (scm_is_pair (handle))
 334     alist = scm_delq1_x (handle, alist);
 335
 336   return alist;
 337 }
 338 #undef FUNC_NAME
 339
 340
 341 SCM_DEFINE (scm_assv_remove_x, "assv-remove!", 2, 0, 0,
 342             (SCM alist, SCM key),
 343             "Behaves like @code{assq-remove!} but uses @code{eqv?} for key comparison.")
 344 #define FUNC_NAME s_scm_assv_remove_x
 345 {
 346   SCM handle;
 347
 348   handle = scm_sloppy_assv (key, alist);
 349   if (scm_is_pair (handle))
 350     alist = scm_delq1_x (handle, alist);
 351
 352   return alist;
 353 }
 354 #undef FUNC_NAME
 355
 356
 357 SCM_DEFINE (scm_assoc_remove_x, "assoc-remove!", 2, 0, 0,
 358             (SCM alist, SCM key),
 359             "Behaves like @code{assq-remove!} but uses @code{equal?} for key comparison.")
 360 #define FUNC_NAME s_scm_assoc_remove_x
 361 {
 362   SCM handle;
 363
 364   handle = scm_sloppy_assoc (key, alist);
 365   if (scm_is_pair (handle))
 366     alist = scm_delq1_x (handle, alist);
 367
 368   return alist;
 369 }
 370 #undef FUNC_NAME
 371
 372
 373 \f
 374
 375
 376
 377 void
 378 scm_init_alist ()
 379 {
 380 #include "libguile/alist.x"
 381 }
 382
 383
 384 /*
 385   Local Variables:
 386   c-file-style: "gnu"
 387   End:
 388 */