Added Unlambda parser

1 files changed, 71 insertions, 0 deletions

diff --git a/Unlambda/Parser.hs b/Unlambda/Parser.hs
new file mode 100644
index 0000000..b6afbea
--- /dev/null
+++ b/Unlambda/Parser.hs
@@ -0,0 +1,71 @@
+module Unlambda.Parser (
+    UnlambdaTerm(..),
+
+	parseUnlambda
+    ) where
+
+
+import Control.Applicative( some )
+import Text.ParserCombinators.Parsec
+
+
+
+data UnlambdaTerm = S | K | I | V | R | D | C
+                  | Dot { cha :: Char }
+	              | App { func :: UnlambdaTerm
+                        , arg :: UnlambdaTerm }
+    deriving (Eq, Show)
+
+
+
+
+parseUnlambda :: String -> Either ParseError UnlambdaTerm
+parseUnlambda = parse unlambda "error"
+
+
+
+unlambda = do
+	whiteSpace
+	t <- term
+	eof
+	return t
+
+
+term  =  (try app)
+     <|> (try s)
+     <|> (try k)
+     <|> (try i)
+     <|> (try v)
+     <|> (try r)
+     <|> (try d)
+     <|> (try c)
+     <|> (try dot)
+     <?> "unlambda term"
+
+
+app = do
+	char '`'
+	whiteSpace
+	f <- term
+	x <- term
+	return (App f x)
+
+
+s = char 's' >> whiteSpace >> return S
+k = char 'k' >> whiteSpace >> return K
+i = char 'i' >> whiteSpace >> return I
+v = char 'v' >> whiteSpace >> return V
+r = char 'r' >> whiteSpace >> return R
+d = char 'd' >> whiteSpace >> return D
+c = char 'c' >> whiteSpace >> return C
+
+
+dot = do
+	char '.'
+	c <- noneOf("")
+	whiteSpace
+	return (Dot c)
+
+
+whiteSpace = many (oneOf "\t\n\r ")
+