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

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