RE: [Haskell-cafe] SYB and opaque types

| I know that the warnings about gunfold, toConstr and dataTypeOf are | harmless but how would I define them to avoid the warnings? I guess you could define them in the instance to be error calls: instance Data SourcePos where gfoldl r k x = k x gunfold = error "gunfold:SourcePos" ...etc.. That way you are making it clear that you didn't leave them out by accident. | Also, the definition of strip above requires -fno-monomorphism- | restriction. Should I not worry about it? The code runs just fine, | locations are being stripped and tests pass. Best thing is to give 'strip' a type signature; then it'll work regardless of flags. Simon