[Haskell-cafe] Lifting a value into a DataKind

[Ivan Lazar Miljenovic]

Thanks for the suggestion; I think singletons is a bit of a large
hammer for a small bit of extra functionality I was thinking of adding
though (especially with people needing to use TH to make their
datatypes instances of SingI as well).

On 8 February 2017 at 12:55, Richard Eisenberg <rae at cs.brynmawr.edu> wrote:
> The singletons library's `toSing` (or `withSing`) may be what you want. Note that if you use Proxy, you won't be able to make any runtime decisions on the choice of `b`.
>
> Richard
>
>> On Feb 7, 2017, at 6:55 PM, Ivan Lazar Miljenovic <ivan.miljenovic at gmail.com> wrote:
>>
>> Is it possible to automatically lift an arbitrary value into a type?
>> i.e. I'm after a function of type `a -> Proxy (b :: a)`.
>>
>> More specifically, I'm wanting to be able to write a function that can
>> convert an Enum (e.g. Bool or Ord) into such a Proxy, so I can
>> actually write a function that looks like: `a -> (forall b. Proxy (b
>> :: a) -> r) -> r` and use the `a` type as a selector value (to e.g.
>> choose between type class instances).
>>
>> --
>> Ivan Lazar Miljenovic
>> Ivan.Miljenovic at gmail.com
>> http://IvanMiljenovic.wordpress.com
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>



-- 
Ivan Lazar Miljenovic
Ivan.Miljenovic at gmail.com
http://IvanMiljenovic.wordpress.com