51 lines
2.2 KiB
Haskell
51 lines
2.2 KiB
Haskell
module BC.Eval (eval) where
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import BC.Types
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eval :: [Value] -> Value
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eval [x@(BInt _)] = x
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eval [x@(BFloat _)] = x
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eval [x@(BErr _)] = x
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eval [(BOp x)] = BErr ("operation " ++ x ++ " requires arguments")
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eval [] = BOp ""
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eval l = treeEval l [] []
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treeEval :: [Value] -> [Value] -> [Value] -> Value
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treeEval [] [] (num:_) = num
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treeEval [] ops nums = handleOp [] ops nums
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treeEval (x@(BInt _):xy) ops nums = treeEval xy ops (x:nums)
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treeEval (x@(BFloat _):xy) ops nums = treeEval xy ops (x:nums)
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treeEval expr@(x@(BOp _):xy) ops@(op:_) nums =
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if precedence x > precedence op
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then treeEval xy (x:ops) nums
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else handleOp expr ops nums
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treeEval (x@(BOp _):xy) [] nums = treeEval xy [x] nums
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handleOp :: [Value] -> [Value] -> [Value] -> Value
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handleOp expr (op:ops) (op2:(op1:nums)) =
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treeEval expr ops ((evalOp op op1 op2):nums)
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handleOp expr ((BOp op):ops) _ = BErr ("Not enough arguments to operation " ++ op)
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evalOp :: Value -> Value -> Value -> Value
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evalOp (BOp "*") (BInt x) (BInt y) = BInt $ x * y
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evalOp (BOp "/") (BInt x) (BInt y) = BInt $ quot x y
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evalOp (BOp "+") (BInt x) (BInt y) = BInt $ x + y
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evalOp (BOp "-") (BInt x) (BInt y) = BInt $ x - y
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evalOp (BOp "^") (BInt x) (BInt y) = BInt $ x ^ y
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evalOp (BOp "*") (BFloat x) (BInt y) = BFloat $ x * fromIntegral y
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evalOp (BOp "/") (BFloat x) (BInt y) = BFloat $ x / fromIntegral y
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evalOp (BOp "+") (BFloat x) (BInt y) = BFloat $ x + fromIntegral y
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evalOp (BOp "-") (BFloat x) (BInt y) = BFloat $ x - fromIntegral y
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evalOp (BOp "^") (BFloat x) (BInt y) = BFloat $ x ** fromIntegral y
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evalOp (BOp "*") (BInt x) (BFloat y) = BFloat $ fromIntegral x * y
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evalOp (BOp "/") (BInt x) (BFloat y) = BFloat $ fromIntegral x / y
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evalOp (BOp "+") (BInt x) (BFloat y) = BFloat $ fromIntegral x + y
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evalOp (BOp "-") (BInt x) (BFloat y) = BFloat $ fromIntegral x - y
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evalOp (BOp "^") (BInt x) (BFloat y) = BFloat $ fromIntegral x ** y
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evalOp (BOp "*") (BFloat x) (BFloat y) = BFloat $ x * y
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evalOp (BOp "/") (BFloat x) (BFloat y) = BFloat $ x / y
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evalOp (BOp "+") (BFloat x) (BFloat y) = BFloat $ x + y
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evalOp (BOp "-") (BFloat x) (BFloat y) = BFloat $ x - y
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evalOp (BOp "^") (BFloat x) (BFloat y) = BFloat $ x ** y
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evalOp _ _ _ = BInt 0
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