Parser and co-parser for Data.URI.Scheme

[Lucu.git] / Data / URI / Internal / Scheme.hs

diff --git a/Data/URI/Internal/Scheme.hs b/Data/URI/Internal/Scheme.hs
index d77fdb5f184ea333d1aab8049f64ea56c37fa985..2e3ba24efa7ac59a9e2c999910e7275f5713aaf1 100644 (file)
--- a/Data/URI/Internal/Scheme.hs
+++ b/Data/URI/Internal/Scheme.hs
@@ -1,19 +1,30 @@
 {-# LANGUAGE
     DeriveDataTypeable
+  , FlexibleInstances
   , GeneralizedNewtypeDeriving
+  , MultiParamTypeClasses
   , StandaloneDeriving
+  , TemplateHaskell
+  , TypeSynonymInstances
   , UnicodeSyntax
   #-}
 module Data.URI.Internal.Scheme
     ( Scheme
-    , unsafeCreateScheme
     )
     where
 import Data.Ascii (CIAscii)
+import qualified Data.Ascii as A
+import Data.Attoparsec.Char8
+import qualified Data.ByteString.Char8 as BS
 import Data.CaseInsensitive
+import Data.Convertible.Base
+import Data.Default
 import Data.Hashable
 import Data.String
+import Data.URI.Internal
 import Data.Typeable
+import Prelude hiding (takeWhile)
+import Prelude.Unicode
 
 -- |'Scheme' names consist of a non-empty sequence of characters
 -- beginning with a letter and followed by any combination of letters,
@@ -27,14 +38,37 @@ newtype Scheme = Scheme CIAscii
              , Show
              , Typeable
              )
--- scheme = ALPHA *( ALPHA / DIGIT / "+" / "-" / "." )
 
 -- |'isString' is a fast but unsafe way to create 'Scheme' such that
 -- no validation on the string is performed.
 deriving instance IsString Scheme
 
--- |Converts a 'CIAscii' to 'Scheme' without any validation on the
--- string.
-unsafeCreateScheme ∷ CIAscii → Scheme
-{-# INLINE CONLIKE unsafeCreateScheme #-}
-unsafeCreateScheme = Scheme
+instance Default (Parser Scheme) where
+    {-# INLINEABLE def #-}
+    def = do x  ← satisfy first
+             xs ← takeWhile nonFirst
+             return ∘ fromBS $ x `BS.cons` xs
+          <?>
+          "scheme"
+        where
+          {-# INLINE first #-}
+          first = isAlpha_ascii
+          {-# INLINE nonFirst #-}
+          nonFirst c
+              = isAlpha_ascii c ∨
+                c ≡ '+'         ∨
+                c ≡ '-'         ∨
+                c ≡ '.'
+          {-# INLINE fromBS #-}
+          fromBS = Scheme ∘ A.toCIAscii ∘ A.unsafeFromByteString
+
+instance ConvertSuccess Scheme CIAscii where
+    {-# INLINE convertSuccess #-}
+    convertSuccess (Scheme s) = s
+
+instance ConvertAttempt CIAscii Scheme where
+    {-# INLINE convertAttempt #-}
+    convertAttempt = parseAttempt' def ∘ A.fromCIAscii
+
+deriveAttempts [ ([t| Scheme |], [t| CIAscii |])
+               ]