[commit: haddock] master: Implement utility method for extracting variable identifiers from AST. (74de002)

[git at git.haskell.org]

Repository : ssh://git@git.haskell.org/haddock

On branch  : master
Link       : http://git.haskell.org/haddock.git/commitdiff/74de0021815f0642a89017fbb1fbdf18064cb5ea

>---------------------------------------------------------------

commit 74de0021815f0642a89017fbb1fbdf18064cb5ea
Author: Łukasz Hanuszczak <lukasz.hanuszczak at gmail.com>
Date:   Sat Jun 6 19:36:53 2015 +0200

    Implement utility method for extracting variable identifiers from AST.


>---------------------------------------------------------------

74de0021815f0642a89017fbb1fbdf18064cb5ea
 haddock-api/src/Haddock/Backends/Hyperlinker/Ast.hs | 16 ++++++++++++++++
 1 file changed, 16 insertions(+)

diff --git a/haddock-api/src/Haddock/Backends/Hyperlinker/Ast.hs b/haddock-api/src/Haddock/Backends/Hyperlinker/Ast.hs
index abd3ca2..62c0d43 100644
--- a/haddock-api/src/Haddock/Backends/Hyperlinker/Ast.hs
+++ b/haddock-api/src/Haddock/Backends/Hyperlinker/Ast.hs
@@ -1,6 +1,10 @@
+{-# LANGUAGE RankNTypes #-}
+
 module Haddock.Backends.Hyperlinker.Ast where
 
 import qualified GHC
+import Data.Data
+import Control.Applicative
 
 import Haddock.Backends.Hyperlinker.Parser
 
@@ -18,3 +22,15 @@ enrich src =
 
 lookupName :: GHC.RenamedSource -> Span -> Maybe GHC.Name
 lookupName = undefined
+
+everything :: (r -> r -> r) -> (forall a. Data a => a -> r)
+           -> (forall a. Data a => a -> r)
+everything k f x = foldl k (f x) (gmapQ (everything k f) x)
+
+variables :: GHC.RenamedSource -> [(GHC.SrcSpan, GHC.Name)]
+variables =
+    everything (<|>) var
+  where
+    var term = case cast term of
+        (Just (GHC.L sspan (GHC.HsVar sid))) -> pure (sspan, sid)
+        _ -> empty