[Haskell-cafe] monomorphism restriction
ryani.spam at gmail.com
Mon Jun 16 17:22:55 EDT 2008
On 6/11/08, Jonathan Cast <jonathanccast at fastmail.fm> wrote:
> This doesn't apply to f, though --- it has a function type, so the user
> presumably already knows it won't be subject to updating, no?
> Distinguishing functions from variables by the form of declaration,
> rather than the type, seems somewhat questionable to me.
Not necessarily, contrast these two definitions:
f = foldr (+) 0
f_expensive = let n = head $ drop 100000 $ fibs 1 1 in foldr (+) n
With the monomorphism restriction in place, f_expensive only
calculates n once. Without, it gets calculated each time f is
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