1 files changed, 68 insertions, 0 deletions
diff --git a/src/Fractran/Parser.hs b/src/Fractran/Parser.hs
new file mode 100644
index 0000000..95aa954
--- /dev/null
+++ b/src/Fractran/Parser.hs
@@ -0,0 +1,68 @@
+module Fractran.Parser (
+    FractranProgram(..),
+
+    parseFractran
+    ) where
+
+
+import Control.Applicative( some )
+import Text.ParserCombinators.Parsec
+
+
+
+data FractranProgram = FractranProgram { fractions :: [(Int,Int)]
+                                       , initialValue :: Int }
+    deriving (Show, Eq)
+
+
+
+
+parseFractran :: String -> Either ParseError FractranProgram
+parseFractran = parse fractran "error"
+
+
+
+
+fractran = do
+    whiteSpace
+    value <- initVal
+    fractionList <- many intPair
+    eof
+    return (FractranProgram fractionList value)
+
+
+intPair = do
+    numerator <- wholeNumber
+    slash
+    denominator <- positiveNumber
+    whiteSpace
+    return (numerator,denominator)
+
+
+slash  =  char '/'
+      <?> "slash character"
+
+
+initVal = do
+    value <- wholeNumber
+    whiteSpace
+    return value
+
+
+wholeNumber = do
+    value <- some digit
+    return (read value)
+
+
+positiveNumber = do
+    firstDigit <- nonZeroDigit
+    rest <- many digit
+    return (read (firstDigit:rest))
+
+
+nonZeroDigit  =  oneOf "123456789"
+             <?> "non-zero digit"
+
+
+whiteSpace = many (oneOf "\t\n\r ")
+