Hi all,
I'm writing a lot of code that looks like this:
instance WhiteSpaced ClassItem where
removeWS (Method a b c) = Method (removeWS a) (removeWS b) (removeWS c)
removeWS (Declaration b) = Declaration (removeWS b)
Typically, all the way at the end there's an instance that deviates (sometimes the deviating instances are somewhere in the middle). I need to do this for a lot of functions, and a lot of data types, and all I'm doing here is rewriting the data-type declaration in a different syntax (except that you do not know the types of a, b and c from the above). For the sake of maintainability, I want to avoid this code-duplication and focus only on the deviating instances.
How to do better? I don't see how to use generics (in the hope of only writing 'instance WhiteSpaced ClassItem where' instead of the three lines above) for this: the types for a, b and c are all different here. Would this be easier with Template Haskell? (in the hope of only writing $(''something ClassItem) instead of the three lines above)
My main concern is maintainability, an ideal solution is either a clear one-liner or a library import (in the same way that aeson allows me to use generics or Template Haskell without needing to know much about them). Other solutions are welcome too.
Best,
Sebastiaan
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