Changes to Typeable

John Meacham john at
Sun Feb 12 02:44:11 CET 2012

I am not so sure, adding type applications to the language seems
fairly radical and will change many aspects of the language. Something
like Proxy that can be expressed in relatively vanilla haskell and
some handy desugarings is much more attractive to me.

With type apllications you end up with odd cases you need to figure
out,  like forall a b. (a,b) and forall b a. (a,b) meaning different
things maybe depending on the details of the impementation.... Also,
it meshes with a core language based on type applications, like system
F or jhc's PTS. However, it seems quite plausible that there are other
ways of writing haskell compilers. Not that i am opposed to them, I
just think they are way overkill for this situation and any solution
based on them will be ghc-bound for a long time probably.


On Sat, Feb 11, 2012 at 5:23 PM, Roman Leshchinskiy <rl at> wrote:
> On 10/02/2012, at 23:30, John Meacham wrote:
>> something I have thought about is perhaps a special syntax for Proxy, like
>> {:: Int -> Int } is short for (Proxy :: Proxy (Int -> Int)). not sure whether
>> that is useful enough in practice though, but could be handy if we are throwing
>> around types a lot.
> We really need explicit syntax for type application. There are already a lot of cases where we have to work around not having it (e.g., Storable) and with the new extensions, there are going to be more and more of those.
> Roman

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