Changes between Version 3 and Version 4 of FlexibleContexts


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Timestamp:
Dec 13, 2005 12:19:34 AM (10 years ago)
Author:
ross@…
Comment:

--

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  • FlexibleContexts

    v3 v4  
    77
    88In Haskell 98,
    9  * contexts of type signarures, `newtype` and `data` declarations consist of assertions of the form C v or C (v t1 ... tn), where v is a type variable.  Contexts on `newtype` and `data` declarations are RemovalCandidates.
     9 * contexts of type signatures, `newtype` and `data` declarations consist of assertions of the form C v or C (v t,,1,, ... t,,n,,), where v is a type variable.
    1010 * contexts of `instance` and `class` declarations consist of assertions of the form C v, where v is a type variable.
    1111The proposal is that class arguments in contexts of type signatures and `class` declarations may be arbitrary types, e.g.
     
    1313g :: (C [a], D (a -> b)) => [a] -> b
    1414}}}
    15 (Similar relaxation of `instance` declarations leads to UndecidableInstances.)
     15(Similar relaxation of `instance` declarations leads to UndecidableInstances.
     16Contexts on `newtype` and `data` declarations are RemovalCandidates.)
    1617
    1718== References ==
     
    5556
    5657== Cons ==
    57  * Complicated context reduction story
    58  * Deferred error checking
     58 * complicated context reduction story
     59 * deferred error checking