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Error in #'list-length if LIST is dotted; check for this error with #'mapcar src/ChangeLog addition: 2010-11-06 Aidan Kehoe <kehoea@parhasard.net> * fns.c (Flist_length): Error if LIST is dotted in this function; document this behaviour. tests/ChangeLog addition: 2010-11-06 Aidan Kehoe <kehoea@parhasard.net> * automated/lisp-tests.el (malformed-list): Check that #'mapcar, #'map and #'list-length throw this error when appropriate.
author Aidan Kehoe <kehoea@parhasard.net>
date Sat, 06 Nov 2010 14:51:13 +0000
parents 99de5fd48e87
children 9f738305f80f
comparison
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5298:99006e0b3a84 5299:28651c24b3f8
343 for shortest_length_among_sequences(), below, for the various sequence 343 for shortest_length_among_sequences(), below, for the various sequence
344 functions that can usefully operate on circular lists. */ 344 functions that can usefully operate on circular lists. */
345 345
346 DEFUN ("list-length", Flist_length, 1, 1, 0, /* 346 DEFUN ("list-length", Flist_length, 1, 1, 0, /*
347 Return the length of LIST. Return nil if LIST is circular. 347 Return the length of LIST. Return nil if LIST is circular.
348 Error if LIST is dotted.
348 */ 349 */
349 (list)) 350 (list))
350 { 351 {
351 Lisp_Object hare, tortoise; 352 Lisp_Object hare, tortoise;
352 Elemcount len; 353 Elemcount len;
355 CONSP (hare) && (! EQ (hare, tortoise) || len == 0); 356 CONSP (hare) && (! EQ (hare, tortoise) || len == 0);
356 hare = XCDR (hare), len++) 357 hare = XCDR (hare), len++)
357 { 358 {
358 if (len & 1) 359 if (len & 1)
359 tortoise = XCDR (tortoise); 360 tortoise = XCDR (tortoise);
361 }
362
363 if (!LISTP (hare))
364 {
365 signal_malformed_list_error (list);
360 } 366 }
361 367
362 return EQ (hare, tortoise) && len != 0 ? Qnil : make_int (len); 368 return EQ (hare, tortoise) && len != 0 ? Qnil : make_int (len);
363 } 369 }
364 370