Re: remove

[espen@coli.uni-sb.de (Espen J. Vestre)]

In article <SIMON.92Nov23130108@liasg2.epfl.ch> Simon Leinen,
simon@lia.di.epfl.ch writes:
>Espen is correct in that Hallvard's REMOVE variant isn't
>tail-recursive and may therefore cause problems with long lists.  One
>could code an iterative tail-preserving version (which might be slower).
>
>But I did some benchmarking on Sun-4s under Allegro and CMU CL, and even
>on longish lists (like 1000 elements or so), Hallvard's FASTER-REMOVE
>performed better on the whole than the system-provided REMOVE versions.
>I would bet that at least 90% of the uses of REMOVE would benefit from
>using FASTER-REMOVE.

Yes, especially if you take into account that if you're using very long
lists as your data structures, you are probably using the wrong kind of
data structure.
I guess a lot of programs might benefit even more from _memoizing_ the
remove function, i.e. if the program is using remove to filter the same
list again and again, it would benefit from knowing that, e.g., a given
value isn't present in that list at all.
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Espen J. Vestre,                          espen@coli.uni-sb.de
Universitaet des Saarlandes,        
Computerlinguistik, Gebaeude 17.2 
Im Stadtwald,                          tel. +49 (681) 302 4501
D-6600 SAARBRUECKEN, Germany           fax. +49 (681) 302 4351
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