Re: [Haskell-cafe] Computing the multiplication table of a group using the GHC inliner ; )

2011/3/22 Daniel Schüssler :

Hello,

turns out that you can define the group operation of the symmetric group on 3 elements in this abstract way (via the isomorphism to the group of bijective functions from a three-element type to itself):

       s3mult g2 g1 = fromFun (toFun g2 . toFun g1)

and convince GHC to compile it down to a nested case statement. It even somehow made the left multiplication with the identity non-strict. Just thought it's neat ;)

That's quite fantastic. Antoine