Add stringCI

LICENSE

@@ -1,4 +1,4 @@
-Copyright (c) 2011 Simon Hengel <sol@typeful.net>
+Copyright (c) 2011, 2012 Simon Hengel <sol@typeful.net>
 
 Permission is hereby granted, free of charge, to any person obtaining a copy
 of this software and associated documentation files (the "Software"), to deal

attoparsec-parsec.cabal

@@ -3,7 +3,7 @@ version:          3.1.2.0
 synopsis:         An Attoparsec compatibility layer for Parsec
 license:          MIT
 license-file:     LICENSE
-copyright:        (c) 2011 Simon Hengel
+copyright:        (c) 2011, 2012 Simon Hengel
 author:           Simon Hengel
 maintainer:       Simon Hengel <sol@typeful.net>
 build-type:       Simple

src/Data/Attoparsec/Text/Parsec.hs

@@ -39,7 +39,7 @@ module Data.Attoparsec.Text.Parsec (
 
 -- * Efficient string handling
 , string
--- , stringCI
+, stringCI
 , skipSpace
 , skipWhile
 -- , I.scan
@@ -72,6 +72,7 @@ module Data.Attoparsec.Text.Parsec (
 ) where
 
 import           Prelude hiding (take, takeWhile)
+import           Data.Char (toLower, toUpper)
 import           Data.Text   (Text)
 import qualified Data.Text as Text
 import qualified Data.Text.Lazy as L
@@ -145,6 +146,21 @@ space = Parsec.space
 string :: String -> Parser Text
 string s = Text.pack <$> Parsec.string s
 
+-- | Satisfy a literal string, ignoring case.
+--
+-- NOTE: No proper case folding is done, yet.  Currently @stringCI s@ is just
+--
+-- > char (toLower c) <|> char (toUpper c)
+--
+-- for each character of @s@.  The implementation from @Data.Attoparsec.Text@
+-- tries to do proper case folding, but is actually buggy (see
+-- <https://github.com/bos/attoparsec/issues/6>).  As long as you deal with
+-- characters from the ASCII range, both implementations should be fine.
+stringCI :: Text -> Parser Text
+stringCI = fmap Text.pack . sequence . map f . Text.unpack
+  where
+    f c = char (toLower c) <|> char (toUpper c)
+
 -- | Skip over white space.
 skipSpace :: Parser ()
 skipSpace = Parsec.spaces

test/Spec.hs

@@ -36,3 +36,10 @@ spec = do
 
     it "consumes nothing, if n is negative" $ do
       parseOnly ((,) <$> take (-3) <*> takeText) "foobar" `shouldBe` Right ("", "foobar")
+
+  describe "stringCI" $ do
+    it "ignores case" $ do
+      parseOnly (stringCI "fooBAR") "FOObar" `shouldBe` Right "FOObar"
+
+    it "does proper case folding" $ (const . pending) "ignored" $ do
+      parseOnly (stringCI "dass") "da\223" `shouldBe` Right "da\223"