Short cut fusion

Revision as of 09:28, 18 January 2008 by Janis (Talk | contribs)

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Short cut fusion is an optimizer method that merges some function calls into one.

E.g.

map f . map g

can be substituted by

map (f . g)

and

filter p . filter q

can be substituted by

filter (\x -> q x && p x)

It can also help to remove intermediate data structures.

E.g. computing

sum [1..n]

does not require an explicit list structure, and the expression is actually translated into a simple loop.