+ readPrec = choice [ parseParens
+ , parseNum
+ , parseVar
+ , parseCall
+ , parseIf
+ , parseBinOp "+" Add
+ , parseBinOp "-" Sub
+ , parseBinOp "*" Mul
+ , parseBinOp ">" (Cmp GT)
+ , parseBinOp "<" (Cmp LT)
+ , parseBinOp "==" (Cmp EQ)
+ ]
+ where parseParens = step $ lift $
+ between (char '(') (char ')') (readS_to_P reads)
+ parseNum = Num <$> readPrec
+ parseVar = Var <$> lift (munch1 isAlpha)
+ parseCall = do
+ func <- lift (munch1 isAlpha)
+ params <- lift $ between (char '(') (char ')') $
+ sepBy (readS_to_P reads)
+ (skipSpaces >> char ',' >> skipSpaces)
+ return (Call func params)
+ parseBinOp s typ = step $ do