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last edited 9 years ago by test1 |
Edit detail for #432 List doesn't check for circularity in length revision 2 of 6
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Editor: Bill Page
Time: 2008/09/01 12:18:59 GMT-7 |
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| Note: fix typo and add ref | ||
changed: -We should either fix the documentation (saying, that this is the case), or check for circularity. This could be done by calling 'INTEGER-LENGTH' in 'ILIST', for example. - We should either fix the documentation (saying, that this is the case), or check for circularity. This could be done by calling 'LIST_-LENGTH' instead of 'LENGTH' in 'ILIST', for example. According to the common lisp standard list-length returns nil if the list is circular. http://www.lispworks.com/documentation/HyperSpec/Body/f_list_l.htm
axiom
u:= [9,2,4,7]; concat! (u, [1,2,42]); end := rest(u,4); part:=rest(u,2); setrest!(end, part);
Type: List PositiveInteger?
Asking for the number of elements of u will exhibit lisp-implementation-dependend behaviour, ranging from an error to an infinite loop.
We should either fix the documentation (saying, that this is the case), or check for circularity. This could be done by calling LIST_-LENGTH instead of LENGTH in ILIST, for example.
According to the common lisp standard list-length returns nil if the list is circular.
http://www.lispworks.com/documentation/HyperSpec/Body/f_list_l.htm