Re: [Haskell-cafe] GHC API - list all exports of a module

Hi Erik, On 02.02.2015 12:55, Erik Hesselink wrote:

On Mon, Feb 2, 2015 at 12:46 PM, Jochen Keil wrote:

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Hello Peter,

On 02.02.2015 12:31, Peter Simons wrote:

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Hi Jochen,

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My main goal would be to have a program which takes two modules of different versions, compare them and highlight the differences between them.

maybe http://hackage.haskell.org/package/hackage-diff would work for your purposes?

Thanks for the hint, this looks pretty good.

One thing though: hackage-diff uses haskell-src-exts for parsing modules. Does haskell-src-exts re-use the GHC API or does it run its own parser? (from a quick glance I'd say the latter case)

There are basically two routes to choose from with such a tool (of which a few already exist, I think): you can use GHC and its API, like you're doing, or you can use haskell-src-exts, which is a separate parser, and use haskell-names for name resolution (and haskell-packages for dependency information). Sadly there's no haskell-type-exts for typechecking (yet). The GHC route is probably more powerful, the haskell-suite route is simpler and doesn't depend on GHC.

thanks for the clarification! Indeed it seems to me that the GHC approach is more powerful, because after running the typechecker I would have the AST available for comparing modules (did I get this right?). Drawback would obviously be the need for running the typechecker. :) So, just for the sake of my curiosity: Is there a way to get the exported declarations (and not just the RdrNames) from GHC without running the typechecker? I don't understand why it's necessary to run the typechecker in order to get this list. The parser already returns a list with all declarations, so shouldn't it be possible to filter this list for only the exported ones? Thanks, Jochen