[Haskell-cafe] Usage question with TemplateHaskell and Generic

José Pedro Magalhães jpm at cs.uu.nl
Mon Nov 7 12:41:33 CET 2011


I'm not sure I understand your question. But if you mean that you want to
retrieve the type variable names, as they were defined in the source, then
I can tell you that the generic deriving mechanism cannot do this.


On Sun, Nov 6, 2011 at 14:35, Magicloud Magiclouds <
magicloud.magiclouds at gmail.com> wrote:

> Hi,
>  I'd like to simpler the work of deriving MyClass. And I have two
> ways to do: TemplateHaskell "$(derivingMyClass)", or Generic "deriving
> (MyClass)".
>  Since I need to get the type name in the deriving, then I met this
> question: If I have "data A b = C b", then with TemplateHaskell, the
> type would be "VarT b", which means at compile time, I cannot get the
> exact type, so the type name would be "b".
>  So I wonder if this could be resolved by TemplateHaskell, or Generic
> is the only choice.
> PS: I have not tried to do this in Generic.
> --
> 竹密岂妨流水过
> 山高哪阻野云飞
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