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Changes between Version 2 and Version 3 of ExistentialQuantification

v2	v3
6	6	== Brief Explanation ==
7	7
	8	Local existential quantification of type variables in a data constructor,
	9	introduced with `forall` before the data constructor, e.g.
	10	{{{
	11	data Accum a = forall s. MkAccum s (a -> s -> s) (s -> a)
	12	}}}
	13	The `forall` is justified by the type of the data constructor:
	14	{{{
	15	MkAccum :: s -> (a -> s -> s) -> (s -> a) -> Accum a
	16	}}}
	17	but [http://www.haskell.org/pipermail/haskell/2003-June/011995.html some have suggested] using `exists` instead to avoid confusion with PolymorphicComponents.
8	18	== References ==
9	19	* [http://www.cs.luc.edu/users/laufer/papers/toplas94.pdf Polymorphic Type Inference and Abstract Data Types] by K. Läufer and M. Odersky, in TOPLAS, Sep 1994.
…	…
37	47
38	48	== Pros ==
39
	49	* quite handy for representations that delay composition or application, e.g. objects, various parser combinator libraries from Utrecht.
40	50
41	51	== Cons ==