For the record, I have started branch 'wip/generics-propeq' and documented it here: https://ghc.haskell.org/trac/ghc/wiki/ActiveBranches Cheers, Gabor On 6/28/14, Gabor Greif wrote:

On 6/27/14, Iavor Diatchki wrote:

...

Hello,

I am a bit unclear on what you mean by "programatically": do you mean from within GHC or is that using something like Template Haskell?

Not TH, just the compiler/typecheck APIs. But the problem is mostly solved already. N.B. I am in the process of extending the generic-deriving mechanism to make it amenable to techniques like propositional equality testing and type-level reasoning.

Cheers and thanks,

Gabor

...

-Iavor

On Thu, Jun 26, 2014 at 3:33 PM, Gabor Greif wrote:

...

Hello devs,

I have

{{{ data D (n :: Symbol) }}}

in my module, and I want to obtain a type

{{{ D "YAY!" }}}

programmatically. Where can I find code that performs this (or something similar)?

1) I have to look up |D| in the current TyEnv (what if it is in a specific module?), 2) I have to build the type index (of kind Symbol), this involves FastString, looks non-trivial, 3) Apply 1) on 2), this is easy.

Any hints welcome!

Thanks and cheers,

Gabor

PS: some morsels I have so far:

for 1) compiler/prelude/PrelNames.lhs:gHC_GENERICS = mkBaseModule (fsLit "GHC.Generics") _______________________________________________ ghc-devs mailing list ghc-devs@haskell.org http://www.haskell.org/mailman/listinfo/ghc-devs