On Mon, Apr 16, 2012 at 6:57 PM, Nicolas Frisby
I'm simulating skolem variables in order to fake universal quantification in constraints via unsafeCoerce.
I'm not familiar with various categories of types from the run-time's perspective, but I'd be surprised if there were NOT a way to use this code to create run-time errors.
Is there a way to make it safer? Perhaps by making Skolem act more like GHC's Any type? Or perhaps like the -> type? I'd like to learn about the varieties of types from the run-time's perspective.
FWIW- I have a version of this concept packaged up in the constraints package. I had a small example that abused flexible instances and MPTCs to cause the single Skolem version of my code to fail. However, when I refined it to use two Skolem variables I wasn't able to derive sufficient Oleggery to break it. That said, an absence of a counter-example isn't a proof that it can't exist. http://hackage.haskell.org/packages/archive/constraints/0.3/doc/html/src/Dat...