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, 53 insertions, 9 deletions

diff --git a/haddock-api/haddock-api.cabal b/haddock-api/haddock-api.cabal
index a91afd36..95af5ef5 100644
--- a/haddock-api/haddock-api.cabal
+++ b/haddock-api/haddock-api.cabal
@@ -124,24 +124,68 @@ test-suite spec
       test
     , src
 
-  -- NB: We only use a small subset of lib:haddock-api here, which
-  --     explains why this component has a smaller build-depends set
   other-modules:
+    Haddock
+    Haddock.Backends.Hoogle
+    Haddock.Backends.Hyperlinker
+    Haddock.Backends.Hyperlinker.Ast
+    Haddock.Backends.Hyperlinker.Renderer
+    Haddock.Backends.Hyperlinker.Utils
+    Haddock.Backends.LaTeX
+    Haddock.Backends.Xhtml
+    Haddock.Backends.Xhtml.Decl
+    Haddock.Backends.Xhtml.DocMarkup
+    Haddock.Backends.Xhtml.Layout
+    Haddock.Backends.Xhtml.Meta
+    Haddock.Backends.Xhtml.Names
+    Haddock.Backends.Xhtml.Themes
+    Haddock.Backends.Xhtml.Types
+    Haddock.Backends.Xhtml.Utils
+    Haddock.Convert
+    Haddock.Doc
+    Haddock.GhcUtils
+    Haddock.Interface
+    Haddock.Interface.AttachInstances
+    Haddock.Interface.Create
+    Haddock.Interface.Json
+    Haddock.Interface.LexParseRn
+    Haddock.Interface.ParseModuleHeader
+    Haddock.Interface.Rename
+    Haddock.Interface.Specialize
+    Haddock.InterfaceFile
+    Haddock.ModuleTree
+    Haddock.Options
+    Haddock.Parser
+    Haddock.Syb
+    Haddock.Types
+    Haddock.Utils
+    Haddock.Utils.Json
+    Haddock.Version
+    Paths_haddock_api
     Haddock.Backends.Hyperlinker.ParserSpec
     Haddock.Backends.Hyperlinker.Parser
     Haddock.Backends.Hyperlinker.Types
 
-  build-depends:
-      ghc         ^>= 8.4
-    , hspec       ^>= 2.4.4
-    , QuickCheck  ^>= 2.10
+  build-depends: Cabal           ^>= 2.0.0
+               , ghc             ^>= 8.4
+               , ghc-paths       ^>= 0.1.0.9
+               , haddock-library ^>= 1.4.6
+               , xhtml           ^>= 3000.2.2
+               , hspec           ^>= 2.4.4
+               , QuickCheck      ^>= 2.10
 
   -- Versions for the dependencies below are transitively pinned by
   -- the non-reinstallable `ghc` package and hence need no version
   -- bounds
-  build-depends:
-      base
-    , containers
+  build-depends: base
+               , array
+               , bytestring
+               , containers
+               , deepseq
+               , directory
+               , filepath
+               , ghc-boot
+               , transformers
 
   build-tool-depends:
     hspec-discover:hspec-discover ^>= 2.4.4