[Haskell-cafe] Usage question with TemplateHaskell and Generic

Magicloud Magiclouds magicloud.magiclouds at gmail.com
Fri Nov 11 16:08:02 CET 2011

2011/11/7 José Pedro Magalhães <jpm at cs.uu.nl>:
> Hi,
> 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.
> Cheers,
> Pedro
> 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
>> _______________________________________________
>> Haskell-Cafe mailing list
>> Haskell-Cafe at haskell.org
>> http://www.haskell.org/mailman/listinfo/haskell-cafe

Thank you. After deeply thinking about this, GH sure does not....


More information about the Haskell-Cafe mailing list