Fixes build failures with ghc-7.10

[0x777]

The pretty package from version 1.1.2.0 started providing Text.PrettyPrint.HughesPJClass which is already provided by prettyclass. This causes the build to fail on ghc-7.10. However, as far as I understand, there is no need for the package to depend on pretty.

So, to fix this error, either remove the dependency on pretty or remove dependency on prettyclass. As @arbn already provided a PR #9 for the first approach, this PR removes the dependency on prettyclass as pretty seems to be more actively developed.

P.S I've no understanding on whether the pretty package is any better than prettyclass in the context of language-glsl.

[hylyh]

I was having the same problem and your changes fixed it, thank you

[vandenoever]

https://github.com/NixOS/nixpkgs/pull/7791 fixes the compilation of language-glsl which removes one error on the way to being able to compile elm-compiler with GHC 7.10.

[vandenoever]

Two errors remain in elm-compiler itself:

src/Parse/Helpers.hs:210:1:
    Non type-variable argument in the constraint: Stream s m Char
    (Use FlexibleContexts to permit this)
    When checking that ‘betwixt’ has the inferred type
      betwixt :: forall b s u (m :: * -> *).
                 Stream s m Char =>
                 Char -> Char -> ParsecT s u m b -> ParsecT s u m b

src/Parse/Helpers.hs:448:5:
    Non type-variable argument in the constraint: Stream s m Char
    (Use FlexibleContexts to permit this)
    When checking that ‘closeShader’ has the inferred type
      closeShader :: forall s u (m :: * -> *) a.
                     Stream s m Char =>
                     ([Char] -> a) -> ParsecT s u m a
    In an equation for ‘shader’:
        shader
          = do { try (string "[glsl|");
                 rawSrc <- closeShader id;
                 case glSource rawSrc of {
                   Left err -> parserFail . show $ err
                   Right tipe -> return ... } }
          where
              closeShader builder = choice [do { ... }, ....]

[vandenoever]

Oops, I meant to comment on a nixpkgs issue.

[peti]

Ping? Is there any particular problem preventing this patch from being merged?

[noteed]

Thank you. https://github.com/noteed/language-glsl/pull/9 (i.e. remove pretty was merged).

[peti]

Will you release a new version to Hackage?

[noteed]

Yes, I will bump the version and push it to Hackage. Probably tomorrow evening. Sorry for the delay.

[noteed]

I've uploaded language-glsl-0.2.0 to Hackage.