28 lines
721 B
Text
28 lines
721 B
Text
inductive Expr
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| Val : Int → Expr
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| Var : String → Expr
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| Add : Expr → Expr → Expr
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| Mul : Expr → Expr → Expr
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open Expr
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def Expr.toString : Expr → String
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| (Val n) := toString n
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| (Var x) := x
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| (Add f g) := "(" ++ Expr.toString f ++ " + " ++ Expr.toString g ++ ")"
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| (Mul f g) := "(" ++ Expr.toString f ++ " * " ++ Expr.toString g ++ ")"
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instance : HasToString Expr :=
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⟨Expr.toString⟩
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partial def addAux : Expr → Expr → Expr
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| f (Add (Val n) g) := addAux (Val n) (addAux f g)
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| f g := Add f g
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def add (a b : Expr) : Expr :=
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addAux a b
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def main (xs : List String) : IO UInt32 :=
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do let x := Var "x";
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IO.println (add (Val 1) (Add (Mul (Val 2) x) x));
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pure 0
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