From 77605c6daf54016cf73d156bb99e021d5e18971b Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Daniel=20Gr=C3=B6ber?= <dxld@darkboxed.org>
Date: Thu, 1 May 2014 01:48:49 +0200
Subject: [PATCH] Add `fromInstalledPackageId`

---
 Language/Haskell/GhcMod/GhcPkg.hs | 10 ++++++++++
 ghc-mod.cabal                     |  2 ++
 2 files changed, 12 insertions(+)

diff --git a/Language/Haskell/GhcMod/GhcPkg.hs b/Language/Haskell/GhcMod/GhcPkg.hs
index fa915f6..178afd9 100644
--- a/Language/Haskell/GhcMod/GhcPkg.hs
+++ b/Language/Haskell/GhcMod/GhcPkg.hs
@@ -6,6 +6,7 @@ module Language.Haskell.GhcMod.GhcPkg (
   , ghcPkgDbStackOpts
   , ghcDbStackOpts
   , ghcDbOpt
+  , fromInstalledPackageId
   , getSandboxDb
   , getPackageDbStack
   ) where
@@ -16,7 +17,9 @@ import Control.Exception (SomeException(..))
 import qualified Control.Exception as E
 import Data.Char (isSpace,isAlphaNum)
 import Data.List (isPrefixOf, intercalate)
+import Data.List.Split (splitOn)
 import Data.Maybe (listToMaybe, maybeToList)
+import Distribution.Package (InstalledPackageId(..))
 import Language.Haskell.GhcMod.Types
 import Language.Haskell.GhcMod.Utils
 import System.Exit (ExitCode(..))
@@ -92,6 +95,13 @@ packageLine l =
       Just ((Hidden,p),_) -> Just p
       _ -> Nothing
 
+fromInstalledPackageId :: InstalledPackageId -> Maybe Package
+fromInstalledPackageId pid = let
+    InstalledPackageId pkg = pid
+    in case reverse $ splitOn "-" pkg of
+      i:v:rest -> Just (intercalate "-" (reverse rest), v, i)
+      _ -> Nothing
+
 data PackageState = Normal | Hidden | Broken deriving (Eq,Show)
 
 packageLineP :: ReadP (PackageState, Package)
diff --git a/ghc-mod.cabal b/ghc-mod.cabal
index 293e365..7141c4b 100644
--- a/ghc-mod.cabal
+++ b/ghc-mod.cabal
@@ -88,6 +88,7 @@ Library
                       , syb
                       , time
                       , transformers
+                      , split
   if impl(ghc < 7.7)
     Build-Depends:      convertible
                       , Cabal >= 1.10 && < 1.17
@@ -159,6 +160,7 @@ Test-Suite spec
                       , time
                       , transformers
                       , hspec >= 1.8.2
+                      , split
   if impl(ghc < 7.7)
     Build-Depends:      convertible
                       , Cabal >= 1.10 && < 1.17