From a45bfb97b94a046a9bd83cab6b03910af83a496c Mon Sep 17 00:00:00 2001
From: Alan Zimmerman <alan.zimm@gmail.com>
Date: Sat, 24 Aug 2013 19:17:33 +0200
Subject: [PATCH] Exposing lower level API using GhcMonad

---
 Language/Haskell/GhcMod/GHCApi.hs    | 16 +++++------
 Language/Haskell/GhcMod/GHCChoice.hs |  3 ++
 Language/Haskell/GhcModLowLevel.hs   | 41 ++++++++++++++++++++++++++++
 ghc-mod.cabal                        |  1 +
 4 files changed, 53 insertions(+), 8 deletions(-)
 create mode 100644 Language/Haskell/GhcModLowLevel.hs

diff --git a/Language/Haskell/GhcMod/GHCApi.hs b/Language/Haskell/GhcMod/GHCApi.hs
index a96c2d6..0cd27e7 100644
--- a/Language/Haskell/GhcMod/GHCApi.hs
+++ b/Language/Haskell/GhcMod/GHCApi.hs
@@ -57,9 +57,9 @@ importDirs = [".","..","../..","../../..","../../../..","../../../../.."]
 
 data Build = CabalPkg | SingleFile deriving Eq
 
-initializeFlagsWithCradle :: Options -> Cradle -> [GHCOption] -> Bool -> Ghc LogReader
+initializeFlagsWithCradle :: GhcMonad m =>  Options -> Cradle -> [GHCOption] -> Bool -> m LogReader
 initializeFlagsWithCradle opt cradle ghcOptions logging
-  | cabal     = withCabal ||> withoutCabal
+  | cabal     = withCabal |||> withoutCabal
   | otherwise = withoutCabal
   where
     cabal = isJust $ cradleCabalFile cradle
@@ -71,13 +71,13 @@ initializeFlagsWithCradle opt cradle ghcOptions logging
 
 ----------------------------------------------------------------
 
-initSession :: Build
+initSession :: GhcMonad m => Build
             -> Options
             -> [GHCOption]
             -> [IncludeDir]
             -> Maybe [Package]
             -> Bool
-            -> Ghc LogReader
+            -> m LogReader
 initSession build opt cmdOpts idirs mDepPkgs logging = do
     dflags0 <- getSessionDynFlags
     (dflags1,readLog) <- setupDynamicFlags dflags0
@@ -92,7 +92,7 @@ initSession build opt cmdOpts idirs mDepPkgs logging = do
 
 ----------------------------------------------------------------
 
-initializeFlags :: Options -> Ghc ()
+initializeFlags :: GhcMonad m => Options -> m ()
 initializeFlags opt = do
     dflags0 <- getSessionDynFlags
     dflags1 <- modifyFlagsWithOpts dflags0 $ ghcOpts opt
@@ -127,7 +127,7 @@ setFastOrNot dflags Fast = dflags {
   , hscTarget = HscNothing
   }
 
-setSlowDynFlags :: Ghc ()
+setSlowDynFlags :: GhcMonad m => m ()
 setSlowDynFlags = (flip setFastOrNot Slow <$> getSessionDynFlags)
                   >>= void . setSessionDynFlags
 
@@ -135,14 +135,14 @@ setSlowDynFlags = (flip setFastOrNot Slow <$> getSessionDynFlags)
 -- "load" sets a session module graph using "depanal".
 -- But we have to set "-fno-code" to DynFlags before "load".
 -- So, this is necessary redundancy.
-checkSlowAndSet :: Ghc ()
+checkSlowAndSet :: GhcMonad m => m ()
 checkSlowAndSet = do
     fast <- canCheckFast <$> depanal [] False
     unless fast setSlowDynFlags
 
 ----------------------------------------------------------------
 
-modifyFlagsWithOpts :: DynFlags -> [String] -> Ghc DynFlags
+modifyFlagsWithOpts :: GhcMonad m => DynFlags -> [String] -> m DynFlags
 modifyFlagsWithOpts dflags cmdOpts =
     tfst <$> parseDynamicFlags dflags (map noLoc cmdOpts)
   where
diff --git a/Language/Haskell/GhcMod/GHCChoice.hs b/Language/Haskell/GhcMod/GHCChoice.hs
index 0345a7e..4bad3f0 100644
--- a/Language/Haskell/GhcMod/GHCChoice.hs
+++ b/Language/Haskell/GhcMod/GHCChoice.hs
@@ -12,6 +12,9 @@ import GHC
 (||>) :: Ghc a -> Ghc a -> Ghc a
 x ||> y = x `gcatch` (\(_ :: IOException) -> y)
 
+(|||>) :: GhcMonad m => m a -> m a -> m a
+x |||> y = x `gcatch` (\(_ :: IOException) -> y)
+
 ----------------------------------------------------------------
 
 {-| Go to the next 'Ghc' monad by throwing 'AltGhcgoNext'.
diff --git a/Language/Haskell/GhcModLowLevel.hs b/Language/Haskell/GhcModLowLevel.hs
new file mode 100644
index 0000000..5950a1e
--- /dev/null
+++ b/Language/Haskell/GhcModLowLevel.hs
@@ -0,0 +1,41 @@
+-- | Low level access to the ghc-mod library.
+
+module Language.Haskell.GhcModLowLevel (
+  -- * Cradle
+    Cradle(..)
+  , findCradle
+  -- * GHC version
+  , GHCVersion
+  , getGHCVersion
+  -- * Options
+  , Options(..)
+  , OutputStyle(..)
+  , defaultOptions
+  -- * Types
+  , ModuleString
+  , Expression
+  -- * Converting the 'Ghc' monad to the 'IO' monad
+  , withGHC
+  , withGHCDummyFile
+  -- * Low level access
+  , LogReader
+  , GHCOption
+  , initializeFlagsWithCradle
+  , setTargetFile
+  , checkSlowAndSet
+  , getDynamicFlags
+  ) where
+
+import Language.Haskell.GhcMod.Browse
+import Language.Haskell.GhcMod.Check
+import Language.Haskell.GhcMod.Cradle
+import Language.Haskell.GhcMod.Debug
+import Language.Haskell.GhcMod.ErrMsg
+import Language.Haskell.GhcMod.Flag
+import Language.Haskell.GhcMod.GHCApi
+import Language.Haskell.GhcMod.Info
+import Language.Haskell.GhcMod.Lang
+import Language.Haskell.GhcMod.Lint
+import Language.Haskell.GhcMod.List
+import Language.Haskell.GhcMod.Types
+import Language.Haskell.GhcMod.CabalApi
diff --git a/ghc-mod.cabal b/ghc-mod.cabal
index d38cda4..f27bbd4 100644
--- a/ghc-mod.cabal
+++ b/ghc-mod.cabal
@@ -40,6 +40,7 @@ Library
   Default-Language:     Haskell2010
   GHC-Options:          -Wall
   Exposed-Modules:      Language.Haskell.GhcMod
+                        Language.Haskell.GhcModLowLevel
   Other-Modules:        Language.Haskell.GhcMod.Browse
                         Language.Haskell.GhcMod.CabalApi
                         Language.Haskell.GhcMod.Check