On 26 January 2013 15:20, Bas van Dijk wrote:

But in aeson-HEAD it has the following type:

deriveJSON :: Options -> Name -> Q [Dec]

Note that I'm currently working on extending the encoding Options record: * I added a constructorNameModifier :: String -> String which is applied to constructor names and is handy for lower-casing them for example. * I extended the sumEncoding with a ObjectWithSingleField constructor which causes a constructor to be encoded to an object with a single field named after the constructor (modified by the constructorNameModifier) and the value will be the contents of the constructor. * I'm also modifying the GHC Generics code to take the encoding Options into account. This work is happening in my parameterize-generic-encoding-with-options branch: https://github.com/basvandijk/aeson/commits/parameterize-generic-encoding-wi... Bas

Quoting Bas van Dijk :

On 26 January 2013 14:47, wrote:

...

ghc doesn't seem to be unifying deriveJSON (String->String) parameter with id :: a -> a.

It seems you're using aeson HEAD. Note that the deriveJSON from the released aeson-0.6.1.0 as the type:

Thanks for the instant help :) Now I know that versions numbers on github don't necessarily get bumped if there's a breaking change. I got confused when I found the hackage documentation was different . Cheers

deriveJSON :: (String -> String) -> Name -> Q [Dec]

But in aeson-HEAD it has the following type:

deriveJSON :: Options -> Name -> Q [Dec]

Cheers,

Bas