Re: [Haskell-cafe] Is fusion overrated?

Roman Cheplyaka wrote:

Of course I don't claim that fusion is useless -- just trying to understand the problem it solves. Are we saving a few closures and cons cells here?

In addition to what everyone else said, fusion can be a big win when it allows further optimisations. For instance, fusing map (+1) . map (+2) can eliminate 1 addition per iteration. Even without taking allocation into account, most of the reasons for why loop fusion is a worthwhile optimisation in C apply to Haskell, too! Roman