diff --git a/haskell-docs.cabal b/haskell-docs.cabal
--- a/haskell-docs.cabal
+++ b/haskell-docs.cabal
@@ -1,5 +1,5 @@
 name:                haskell-docs
-version:             4.2.3
+version:             4.2.4
 synopsis:            A program to find and display the docs and type of a name
 description:         Given a module name and a name, or just a name, it will find and display
                      the documentation of that name.
@@ -51,6 +51,16 @@
 cabal-version:       >=1.8
 Homepage:            http://github.com/chrisdone/haskell-docs
 Bug-Reports:         http://github.com/chrisdone/haskell-docs/issues
+extra-source-files:
+  src/Haskell/Docs.hs
+  src/Haskell/Docs/Ghc.hs
+  src/Haskell/Docs/Cabal.hs
+  src/Haskell/Docs/Formatting.hs
+  src/Haskell/Docs/Haddock.hs
+  src/Haskell/Docs/Types.hs
+  src/Haskell/Docs/Index.hs
+  src/haddock/Haskell/Docs/HaddockDoc.hs
+  src/haddock-api/Haskell/Docs/HaddockDoc.hs
 
 library
   ghc-options:         -O2 -Wall
diff --git a/src/haddock/Haskell/Docs/HaddockDoc.hs b/src/haddock/Haskell/Docs/HaddockDoc.hs
new file mode 100644
--- /dev/null
+++ b/src/haddock/Haskell/Docs/HaddockDoc.hs
@@ -0,0 +1,117 @@
+{-# LANGUAGE CPP #-}
+-- | Pre-haddock-api.
+
+module Haskell.Docs.HaddockDoc where
+
+import           Control.Arrow
+import           Control.Exception (try,IOException)
+import           Control.Monad
+import           Control.Monad
+import           Data.Char
+import           Data.Either
+import           Data.Function
+import           Data.List
+import           Data.List
+import           Data.Map (Map)
+import qualified Data.Map as M
+import           Documentation.Haddock
+import           Documentation.Haddock
+import           GHC hiding (verbosity)
+import           GHC hiding (verbosity)
+import           GhcMonad (liftIO)
+import           GhcMonad (liftIO)
+import           Haskell.Docs.Cabal
+import           Haskell.Docs.Ghc
+import           Haskell.Docs.Ghc
+import           Haskell.Docs.Types
+import           Haskell.Docs.Types
+import           Name
+import           Name
+import           PackageConfig
+import           Packages
+
+-- | Render the doc.
+doc :: Doc String -> String
+doc DocEmpty = ""
+doc (DocAppend a b) = doc a ++ doc b
+doc (DocString str) = normalize str
+doc (DocParagraph p) = doc p ++ "\n"
+doc (DocModule m) = m
+doc (DocEmphasis e) = "*" ++ doc e ++ "*"
+doc (DocMonospaced e) = "`" ++ doc e ++ "`"
+doc (DocUnorderedList i) = unlines (map (("* " ++) . doc) i)
+doc (DocOrderedList i) = unlines (zipWith (\j x -> show j ++ ". " ++ doc x) [1 :: Int ..] i)
+doc (DocDefList xs) = unlines (map (\(i,x) -> doc i ++ ". " ++ doc x) xs)
+doc (DocCodeBlock bl) = unlines (map ("    " ++) (lines (doc bl))) ++ "\n"
+doc (DocAName name) = name
+doc (DocExamples exs) = unlines (map formatExample exs)
+
+#if MIN_VERSION_haddock(2,10,0)
+-- The header type is unexported, so this constructor is useless.
+doc (DocIdentifier i) = i
+doc (DocWarning d) = "Warning: " ++ doc d
+#else
+doc (DocPic pic) = pic
+doc (DocIdentifier i) = intercalate "." i
+#endif
+
+#if MIN_VERSION_haddock(2,11,0)
+doc (DocIdentifierUnchecked (mname,occname)) =
+  moduleNameString mname ++ "." ++ occNameString occname
+doc (DocPic pic) = show pic
+#endif
+
+#if MIN_VERSION_haddock(2,13,0)
+doc (DocHyperlink (Hyperlink url label)) = maybe url (\l -> l ++ "[" ++ url ++ "]") label
+doc (DocProperty p) = "Property: " ++ p
+#else
+doc (DocURL url) = url
+#endif
+
+#if MIN_VERSION_haddock(2,14,0)
+doc (DocBold d) = "**" ++ doc d ++ "**"
+doc (DocHeader _) = ""
+#endif
+
+-- * Get documentation of parts of things
+
+-- | Get a mapping from names to doc string of that name from a
+-- Haddock interface.
+interfaceNameMap :: InstalledInterface -> Map String (Doc String)
+#if MIN_VERSION_haddock(2,10,0)
+interfaceNameMap iface =
+  M.fromList (map (second (fmap getOccString) . first getOccString)
+             (M.toList (instDocMap iface)))
+#else
+interfaceNameMap iface =
+  M.fromList (map (second (fmap getOccString . maybe DocEmpty id . fst) . first getOccString)
+             (M.toList (instDocMap iface)))
+#endif
+
+-- | Get a mapping from names to doc string of that name from a
+-- Haddock interface.
+interfaceArgMap :: InstalledInterface -> Map String (Map Int (Doc Name))
+#if MIN_VERSION_haddock(2,10,0)
+interfaceArgMap iface =
+  M.fromList (map (first getOccString) (M.toList (instArgMap iface)))
+#else
+interfaceArgMap iface = M.fromList (map (second (const M.empty) . first getOccString)
+                                        (M.toList (instDocMap iface)))
+#endif
+
+-- | Strip redundant whitespace.
+normalize :: [Char] -> [Char]
+normalize = go where
+  go (' ':' ':cs) = go (' ':cs)
+  go (c:cs)       = c : go cs
+  go []           = []
+
+-- | Trim either side of a string.
+trim :: [Char] -> [Char]
+trim = reverse . dropWhile isSpace . reverse . dropWhile isSpace
+
+-- | Format an example to plain text.
+formatExample :: Example -> String
+formatExample (Example expression result) =
+  "    > " ++ expression ++
+  unlines (map ("    " ++) result)