Changes between Version 1 and Version 2 of ExistentialQuantifier


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Timestamp:
Feb 14, 2006 11:57:37 AM (9 years ago)
Author:
john@…
Comment:

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  • ExistentialQuantifier

    v1 v2  
    1 
    21= Existential Quantifier =
    32
     
    98sameType :: Any -> Any -> Bool
    109sameType x y = typeOf x == typeOf y
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    1111}}}
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     13When existentials appear in the contravarient position such as above, they can be desugared into rank-n types with foralls. if existentials are allowed in the covarient position, then support for FirstClassExistentials is needed.
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     15
     16== Support ==
     17
     18Jhc currently supports the existential syntax anywhere a type is accepted, but will report an error if one is used in a covariant position.