From 7900ae557ebe8319e43daf9c4202e8acb886317a Mon Sep 17 00:00:00 2001
From: Jed Barber <jjbarber@y7mail.com>
Date: Thu, 6 Feb 2014 01:56:56 +1100
Subject: Completed Fractran parser

---
 Fractran/Parser.hs | 49 +++++++++++++++++++++++++++++++------------------
 1 file changed, 31 insertions(+), 18 deletions(-)

(limited to 'Fractran')

diff --git a/Fractran/Parser.hs b/Fractran/Parser.hs
index 63564d1..19e619f 100644
--- a/Fractran/Parser.hs
+++ b/Fractran/Parser.hs
@@ -1,11 +1,12 @@
 module Parser (
-	FractranProgram(..),
+    FractranProgram(..),
 
-	parseFractran
-	) where
+    parseFractran
+    ) where
 
 
-import Text.Combinators.Parsec
+import Control.Applicative( some )
+import Text.ParserCombinators.Parsec
 
 
 
@@ -15,6 +16,7 @@ data FractranProgram = FractranProgram { fractions :: [(Int,Int)]
 
 
 
+
 parseFractran :: String -> Either ParseError FractranProgram
 parseFractran = parse fractran "error"
 
@@ -22,31 +24,42 @@ parseFractran = parse fractran "error"
 
 
 fractran = do
-	f <- many intPair
-	v <- initVal
-	eof
-	return (FractranProgram f v)
+    value <- initVal
+    fractionList <- many intPair
+    whiteSpace
+    eof
+    return (FractranProgram fractionList value)
 
 
 intPair = do
-	whiteSpace
-	n <- wholeNumber
-	slash
-	d <- wholeNumber
-	return (n,d)
+    whiteSpace
+    numerator <- wholeNumber
+    slash
+    denominator <- positiveNumber
+    return (numerator,denominator)
 
 
 slash = char '/'
 
 
 initVal = do
-	whiteSpace
-	v <- wholeNumber
-	whiteSpace
-	return v
+    whiteSpace
+    value <- wholeNumber
+    return value
+
+
+wholeNumber = do
+    value <- some digit
+    return (read value)
+
+
+positiveNumber = do
+    firstDigit <- nonZeroDigit
+    rest <- many digit
+    return (read (firstDigit:rest))
 
 
-wholeNumber =
+nonZeroDigit = oneOf "123456789"
 
 
 whiteSpace = many (oneOf "\t\n\r ")
-- 
cgit