Re: [Haskell-cafe] What does the `forall` mean ?

Eugene Kirpichov wrote:

2009/11/12 Andrew Coppin :

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Joe Fredette wrote:

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Forall means the same thing as it means in math

...which not everybody already knows about. ;-)

Even I am still not 100% sure how placing forall in different positions does different things. But usually it's not something I need to worry about. :-)

To me it does not look like it does different things: everywhere it denotes universal polymorphism. What do you mean? I might be missing something.

I just meant it's not immediately clear how foo :: forall x. (x -> x -> y) is different from foo :: (forall x. x -> x) -> y It takes a bit of getting used to.