I have a sequence of functions that I wish to fold together using function composition (.). Does it matter if I use foldl or foldr?

e.g.

[[
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.

#g


------------ Graham Klyne For email: http://www.ninebynine.org/#Contact

_______________________________________________
Haskell-Cafe mailing list
[EMAIL PROTECTED]
http://www.haskell.org/mailman/listinfo/haskell-cafe

Reply via email to