Merge pull request #6 from purescript-contrib/additions

Additions

Author: garyb

src/Text/Parsing/StringParser/Combinators.purs

@@ -1,11 +1,13 @@
 module Text.Parsing.StringParser.Combinators where
 
+import Control.Alt ((<|>))
+import Control.Apply ((*>))
 import Data.Maybe (Maybe(..))
-
-import Control.Alt
-
 import Text.Parsing.StringParser
 
+lookAhead :: forall a. Parser a -> Parser a
+lookAhead p = Parser \ps fc sc -> unParser p ps fc (\s _ -> sc s ps)
+
 many :: forall a. Parser a -> Parser [a]
 many p = many1 p <|> return []
 
@@ -100,3 +102,10 @@ choice :: forall a. [Parser a] -> Parser a
 choice []   = fail "Nothing to parse"
 choice [x]  = x
 choice (x:xs) = x <|> choice xs
+
+manyTill :: forall a end. Parser a -> Parser end -> Parser [a]
+manyTill p end = scan
+  where
+  scan = (end *> return []) <|> do x <- p
+                                   xs <- scan
+                                   return (x:xs)

src/Text/Parsing/StringParser/String.purs

@@ -1,8 +1,14 @@
-module Text.Parsing.StringParser.String where
+module Text.Parsing.StringParser.String
+  ( eof
+  , anyChar
+  , anyDigit
+  , string
+  ) where
 
-import Data.Maybe
-import Data.String (charAt, fromChar, length, take, indexOf')
+import Data.Maybe (Maybe(..))
+import Data.String (charAt, fromChar, length, indexOf')
 import Text.Parsing.StringParser
+import qualified Data.String.Regex as Rx
 
 eof :: Parser Unit
 eof = Parser (\s fc sc -> case s of
@@ -15,6 +21,18 @@ anyChar = Parser (\s fc sc -> case s of
     Just chr -> sc (fromChar chr) { str: str, pos: i + 1 }
     Nothing -> fc i (ParseError "Unexpected EOF"))
 
+anyDigit :: Parser String
+anyDigit = Parser \{ str: str, pos: i } fc sc -> case charAt i str of
+  Just chr ->
+    let chrS = fromChar chr
+    in if Rx.test rxDigit chrS
+       then sc chrS { str: str, pos: i + 1 }
+       else fc i (ParseError "Expected digit")
+  Nothing -> fc i (ParseError "Unexpected EOF")
+  where
+  rxDigit :: Rx.Regex
+  rxDigit = Rx.regex "^[0-9]" Rx.noFlags
+
 string :: String -> Parser String
 string nt = Parser (\s fc sc -> case s of
   { str = str, pos = i } | indexOf' nt i str == i -> sc nt { str: str, pos: i + length nt }