Add type synonyms for lazy and strict text flavours

closes haskell#317

src/Data/Text.hs

@@ -53,6 +53,7 @@ module Data.Text
 
     -- * Types
       Text
+    , StrictText
 
     -- * Creation and elimination
     , pack
@@ -238,7 +239,7 @@ import qualified Data.Text.Internal.Fusion.Common as S
 import Data.Text.Encoding (decodeUtf8', encodeUtf8)
 import Data.Text.Internal.Fusion (stream, reverseStream, unstream)
 import Data.Text.Internal.Private (span_)
-import Data.Text.Internal (Text(..), empty, firstf, mul, safe, text, append, pack)
+import Data.Text.Internal (Text(..), StrictText, empty, firstf, mul, safe, text, append, pack)
 import Data.Text.Internal.Unsafe.Char (unsafeWrite, unsafeChr8)
 import Data.Text.Show (singleton, unpack, unpackCString#, unpackCStringAscii#)
 import qualified Prelude as P

src/Data/Text/Internal.hs

@@ -29,6 +29,7 @@ module Data.Text.Internal
     -- * Types
     -- $internals
       Text(..)
+    , StrictText
     -- * Construction
     , text
     , textP
@@ -68,6 +69,9 @@ data Text = Text
     {-# UNPACK #-} !Int     -- ^ length in bytes (not in Char!), pointing to an end of UTF-8 sequence
     deriving (Typeable)
 
+-- | Type synonym for the strict flavour of 'Text'.
+type StrictText = Text
+
 -- | Smart constructor.
 text_ ::
 #if defined(ASSERTS)

src/Data/Text/Internal/Lazy.hs

@@ -21,6 +21,7 @@
 module Data.Text.Internal.Lazy
     (
       Text(..)
+    , LazyText
     , chunk
     , empty
     , foldrChunks
@@ -51,6 +52,9 @@ data Text = Empty
           | Chunk {-# UNPACK #-} !T.Text Text
             deriving (Typeable)
 
+-- | Type synonym for the lazy flavour of 'Text'.
+type LazyText = Text
+
 -- $invariant
 --
 -- The data type invariant for lazy 'Text': Every 'Text' is either 'Empty' or