On Fri, Jan 30, 2015 at 7:05 PM, adam vogt
Hi Greg,
Perhaps a less-invasive way to implement the -XSafe part of your proposal would be to provide a module like:
module Language.Haskell.TH.Safe ( module Language.Haskell.TH, reifyWithoutNameG, ) where import Language.Haskell.TH hiding (runIO, reify*)
where reifyWithoutNameG is the same as reify, except definitions that are out of scope are either missing or modified such that they use NameQ instead of NameG for out-of-scope names.
Thanks, I added this concept to the wiki.
That way there is no new syntax needed, and safe TH can be called by unsafe TH without any conversions.
I think defining another monad like Q that can do less is too inconvenient because you have to disambiguate between Safe.listE and Unsafe.listE, or make those functions more polymorphic (which makes type errors worse). Another option would be if there were
Oh, you are getting into more concrete details now than I have even thought about! For the restricted monad route, we might look into a more capable method of using capabilities that would end up looking like this: reify :: Name -> Restrict (TH :+: Reify) Info runIO :: IO a -> Restrict (TH :+: RunIO) a There are still a lot of details to work out, thanks for getting things started.