Parsec type error with Flexible Contexts
Hi. I wanted to generalize the definitions in Text.Parsec.Language to be able to use them with Parsec Text instead of Parsec String. I'm getting a type error with the following code snippet: http://hpaste.org/72844 I don't really understand the error, specially with regard to the fact that the if I comment one of the marked lines on the code pasted the program build. Any help is welcome. Greetings. -- marcot http://marcot.eti.br/
Hello! I've managed to reduce your code to a much simpler test case (without parsec) but I'm still not sure why this is happening: {-# LANGUAGE MultiParamTypeClasses, FlexibleContexts #-} data D m = D { bar1 :: P m () , bar2 :: P m () } data P m c = P class S m c where foo :: S m () => P m () foo = undefined emptyDef :: S m () => D m emptyDef = D { bar1 = foo , bar2 = foo } haskellStyle :: S m () => D m haskellStyle = emptyDef { bar1 = foo , bar2 = foo } Cheers, -- Felipe.
Here's an even smaller one: {-# LANGUAGE MultiParamTypeClasses, FlexibleContexts #-} data D m = D { bar :: P m () } data P m c = P class S m c where foo :: S m () => P m () foo = undefined emptyDef :: S m () => D m emptyDef = D foo haskellStyle :: S m () => D m haskellStyle = emptyDef { bar = foo } Cheers, -- Felipe.
participants (2)
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Felipe Almeida Lessa -
Marco Túlio Gontijo e Silva