Refactor ModuleName to L.H.S.Module.Name

ModuleName used to live in GHC.Unit.Module.Name. In this commit, the
definition of ModuleName and its associated functions are moved to
Language.Haskell.Syntax.Module.Name according to the current plan
towards making the AST GHC-independent.

The instances for ModuleName for Outputable, Uniquable and Binary were
moved to the module in which the class is defined because these instances
depend on GHC.

The instance of Eq for ModuleName is slightly changed to no longer
depend on unique explicitly and instead uses FastString's instance of
Eq.

1 files changed, 60 insertions, 0 deletions

diff --git a/compiler/Language/Haskell/Syntax/Module/Name.hs b/compiler/Language/Haskell/Syntax/Module/Name.hs
new file mode 100644
index 0000000000..65e64d8700
--- /dev/null
+++ b/compiler/Language/Haskell/Syntax/Module/Name.hs
@@ -0,0 +1,60 @@
+module Language.Haskell.Syntax.Module.Name where
+
+import Prelude
+
+import Data.Data
+import Data.Char (isAlphaNum)
+import Control.DeepSeq
+import qualified Text.ParserCombinators.ReadP as Parse
+import System.FilePath
+
+import GHC.Utils.Misc (abstractConstr)
+import GHC.Data.FastString
+
+-- | A ModuleName is essentially a simple string, e.g. @Data.List@.
+newtype ModuleName = ModuleName FastString deriving (Show, Eq)
+
+instance Ord ModuleName where
+  nm1 `compare` nm2 = stableModuleNameCmp nm1 nm2
+
+instance Data ModuleName where
+  -- don't traverse?
+  toConstr _   = abstractConstr "ModuleName"
+  gunfold _ _  = error "gunfold"
+  dataTypeOf _ = mkNoRepType "ModuleName"
+
+instance NFData ModuleName where
+  rnf x = x `seq` ()
+
+stableModuleNameCmp :: ModuleName -> ModuleName -> Ordering
+-- ^ Compares module names lexically, rather than by their 'Unique's
+stableModuleNameCmp n1 n2 = moduleNameFS n1 `lexicalCompareFS` moduleNameFS n2
+
+moduleNameFS :: ModuleName -> FastString
+moduleNameFS (ModuleName mod) = mod
+
+moduleNameString :: ModuleName -> String
+moduleNameString (ModuleName mod) = unpackFS mod
+
+mkModuleName :: String -> ModuleName
+mkModuleName s = ModuleName (mkFastString s)
+
+mkModuleNameFS :: FastString -> ModuleName
+mkModuleNameFS s = ModuleName s
+
+-- |Returns the string version of the module name, with dots replaced by slashes.
+--
+moduleNameSlashes :: ModuleName -> String
+moduleNameSlashes = dots_to_slashes . moduleNameString
+  where dots_to_slashes = map (\c -> if c == '.' then pathSeparator else c)
+
+-- |Returns the string version of the module name, with dots replaced by colons.
+--
+moduleNameColons :: ModuleName -> String
+moduleNameColons = dots_to_colons . moduleNameString
+  where dots_to_colons = map (\c -> if c == '.' then ':' else c)
+
+parseModuleName :: Parse.ReadP ModuleName
+parseModuleName = fmap mkModuleName
+                $ Parse.munch1 (\c -> isAlphaNum c || c `elem` "_.")
+