30 Nov
2009
30 Nov
'09
5:49 p.m.
michael rice wrote:
From: http://www.haskell.org/haskellwiki/Blow_your_mind#Polynomials
-- splitting in two (alternating) -- "1234567" -> ("1357", "246") -- the lazy match with ~ is necessary for efficiency, especially enabling processing of infinite lists foldr (\a ~(x,y) -> (a:y,x)) ([],[])
This works but can't find (~) operator anywhere. Please explain or site a reference.
This is called a "lazy pattern". See: http://www.haskell.org/tutorial/patterns.html section 4.4 Cheers, Jochem -- Jochem Berndsen | jochem@functor.nl | jochem@牛在田里.com