7 Apr
2002
7 Apr
'02
5:46 a.m.
Hello, this is probably embarrassing, but I just realised that I do not understand why list concatenation operation takes quadratic time if it is associated from left to right (see e.g. 'The Haskell School of Expression' by Hudak, p. 335): cat1 = (++) cat2 = (++) ( [1,2] `cat1` [3,4] ) `cat2` [5,6] My understanding is that cat2 is invoked before cat1, and as soon as the first element of cat1 is available, cat2 starts building its own result. cat2 does not need to wait until the whole list is emitted by cat1, does it? Where is quadratic time complexity? konst