[Haskell] Re: Using implicit parameter constraints in data decl

[Ben Rudiak-Gould]

Benjamin Franksen wrote:

 >data (?val::Bool) => Test = Test { name :: String }
 >
 >is rejected by the compiler:
 >
 >TestBug.hs:3:
 >    Illegal constraint ?val :: Bool
 >    In the context: (?val :: Bool)
 >    While checking the context of the data type declaration for `Test'
 >    In the data type declaration for `Test'
 >
 >which is unfortunate since it means that you cannot put a function that
 >depends on an implicit parameter into a data structure.

Does this do what you want?:

    data Test = Test { name :: (?val::Bool) => String }

-- Ben