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module Evaluator where
data Token
= TokenInt Integer
| TokenAdd
| TokenMultiply
deriving (Eq, Show)
newtype AST = AST [Token]
deriving (Eq, Show)
tokens :: [Token]
tokens =
[ TokenInt 13
, TokenAdd
, TokenInt 2
, TokenMultiply
, TokenInt 4
, TokenAdd
, TokenInt 7
, TokenAdd
, TokenInt 3
, TokenMultiply
, TokenInt 8
]
-- expression -> addition ;
-- addition -> multiplication ( "+" multiplication )* ;
-- multiplication -> terminal ( "*" terminal )* ;
-- terminal -> NUMBER ;
parseExpression :: [Token] -> ([Token], AST)
parseExpression tokens = do
lhs, rest = parseMultiplication tokens
parseMulitplication :: [Token] -> ([Token], AST)
main :: IO ()
main = print $ parse tokens
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