019f8fd211
git-subtree-dir: users/wpcarro git-subtree-mainline:464bbcb15cgit-subtree-split:24f5a642afChange-Id: I6105b3762b79126b3488359c95978cadb3efa789
39 lines
739 B
Haskell
39 lines
739 B
Haskell
module Evaluator where
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data Token
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= TokenInt Integer
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| TokenAdd
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| TokenMultiply
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deriving (Eq, Show)
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newtype AST = AST [Token]
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deriving (Eq, Show)
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tokens :: [Token]
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tokens =
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[ TokenInt 13
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, TokenAdd
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, TokenInt 2
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, TokenMultiply
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, TokenInt 4
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, TokenAdd
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, TokenInt 7
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, TokenAdd
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, TokenInt 3
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, TokenMultiply
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, TokenInt 8
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]
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-- expression -> addition ;
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-- addition -> multiplication ( "+" multiplication )* ;
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-- multiplication -> terminal ( "*" terminal )* ;
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-- terminal -> NUMBER ;
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parseExpression :: [Token] -> ([Token], AST)
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parseExpression tokens = do
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lhs, rest = parseMultiplication tokens
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parseMulitplication :: [Token] -> ([Token], AST)
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main :: IO ()
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main = print $ parse tokens
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