At 14:24 07/07/04 +0200, Henning Thielemann wrote:
On Wed, 7 Jul 2004, Graham Klyne wrote:
> [[ > sss :: [ShowS] > sss = map (++) ["abc","def","ghi","jkl"] > > ssr = foldr (.) id sss > ssl = foldl (.) id sss > > sr = ssr "" > sl = ssl "" > > -- sl == sr == "abcdefghijkl" > -- is there any efficiency difference? > ]] > > Conventional wisdom suggests that foldr is better, but I'm not sure if it > really matters in this case.
foldl performs worse, e.g. for infinite lists it will need infinite time :-)
Of course! And your answer makes me notice an important touchstone when dealing with such questions: "what happens with an infinite list?".
Thanks!
#g
------------ Graham Klyne For email: http://www.ninebynine.org/#Contact
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