Changes to Typeable

[Edward Kmett]

On Mon, Feb 13, 2012 at 3:27 PM, Simon Marlow <marlowsd at gmail.com> wrote:

> On 13/02/12 18:16, Edward Kmett wrote:
>
>> You could probably get away with something like
>>
>> data Proxy = Proxy a
>>
>> class Typeable a where
>>   typeOfProxy :: Proxy a -> TypeRep
>>
>> typeOf :: forall a. Typeable a => a -> TypeRep
>> typeOf = typeOfProxy (Proxy :: Proxy a)
>>
>> which being outside of the class won't contribute to the inference of
>> 'a's kind.
>>
>> This would let you retain the existing functionality.
>>
>
> Simon's version has this:
>
> typeOf :: forall a. Typeable a => a -> TypeRep
> typeOf x = typeRep (getType x) where
>  getType :: a -> Proxy a
>  getType _ = Proxy
>
> (your version is clearer, though)
>
> I'm assuming there's no significance behind your renaming of 'typeRep' to
> 'typeOfProxy'?
>

No significance at all. I probably should have read the page before
commenting. ;)

-Edward
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