Use the GHC lexer for the Hyperlinker backend (#714)

* Start changing to use GHC lexer

* better cpp

* Change SrcSpan to RealSrcSpan

* Remove error

* Try to stop too many open files

* wip

* wip

* Revert "wip"

This reverts commit b605510a195f26315e3d8ca90e6d95a6737553e1.

Conflicts:
	haddock-api/haddock-api.cabal
	haddock-api/src/Haddock/Interface.hs

* Remove pointless 'caching'

* Use dlist rather than lists when finding vars

* Use a map rather than list

* Delete bogus comment

* Rebase followup

Things now run using the GHC lexer. There are still

  - stray debug statements
  - unnecessary changes w.r.t. master

* Cleaned up differences w.r.t. current Haddock HEAD

Things are looking good. quasiquotes in particular look beautiful: the
TH ones (with Haskell source inside) colour/link their contents too!

Haven't yet begun to check for possible performance problems.

* Support CPP and top-level pragmas

The support for these is hackier - but no more hacky than the existing
support.

* Tests pass, CPP is better recognized

The tests were in some cases altered: I consider the new output to be more
correct than the old one....

* Fix shrinking of source without tabs in test

* Replace 'Position'/'Span' with GHC counterparts

Replaces 'Position' -> 'GHC.RealSrcLoc' and 'Span' -> 'GHC.RealSrcSpan'.

* Nits

* Forgot entry in .cabal

* Update changelog

1 files changed, 8 insertions, 6 deletions

diff --git a/haddock-api/src/Haddock/Backends/Hyperlinker/Renderer.hs b/haddock-api/src/Haddock/Backends/Hyperlinker/Renderer.hs
index 15793f0c..27bf7605 100644
--- a/haddock-api/src/Haddock/Backends/Hyperlinker/Renderer.hs
+++ b/haddock-api/src/Haddock/Backends/Hyperlinker/Renderer.hs
@@ -82,7 +82,7 @@ header mcss mjs =
 
 tokenGroup :: SrcMap -> TokenGroup -> Html
 tokenGroup _ (GrpNormal tok@(Token { .. }))
-    | tkType == TkSpace = renderSpace (posRow . spStart $ tkSpan) tkValue
+    | tkType == TkSpace = renderSpace (GHC.srcSpanStartLine tkSpan) tkValue
     | otherwise = tokenSpan tok ! attrs
   where
     attrs = [ multiclass . tokenStyle $ tkType ]
@@ -155,7 +155,7 @@ internalHyperlink name content =
     Html.anchor content ! [ Html.href $ "#" ++ internalAnchorIdent name ]
 
 externalNameHyperlink :: SrcMap -> GHC.Name -> Html -> Html
-externalNameHyperlink (srcs, _) name content = case Map.lookup mdl srcs of
+externalNameHyperlink srcs name content = case Map.lookup mdl srcs of
     Just SrcLocal -> Html.anchor content !
         [ Html.href $ hypSrcModuleNameUrl mdl name ]
     Just (SrcExternal path) -> Html.anchor content !
@@ -165,12 +165,14 @@ externalNameHyperlink (srcs, _) name content = case Map.lookup mdl srcs of
     mdl = GHC.nameModule name
 
 externalModHyperlink :: SrcMap -> GHC.ModuleName -> Html -> Html
-externalModHyperlink (_, srcs) name content = case Map.lookup name srcs of
-    Just SrcLocal -> Html.anchor content !
+externalModHyperlink srcs name content =
+    let srcs' = Map.mapKeys GHC.moduleName srcs in
+    case Map.lookup name srcs' of
+      Just SrcLocal -> Html.anchor content !
         [ Html.href $ hypSrcModuleUrl' name ]
-    Just (SrcExternal path) -> Html.anchor content !
+      Just (SrcExternal path) -> Html.anchor content !
         [ Html.href $ path </> hypSrcModuleUrl' name ]
-    Nothing -> content
+      Nothing -> content
 
 
 renderSpace :: Int -> String -> Html