26 lines
597 B
Text
26 lines
597 B
Text
import Lean
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open Lean
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def mkBig : Nat → Expr
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| 0 => mkConst `a
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| (n+1) => mkApp2 (mkConst `f []) (mkBig n) (mkBig n)
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def replaceTest (e : Expr) : Expr :=
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e.replace $ fun e => match e with
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| Expr.const c _ _ => if c == `f then mkConst `g else none
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| _ => none
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#eval replaceTest $ mkBig 4
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#eval (replaceTest $ mkBig 128).getAppFn
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def findTest (e : Expr) : Option Expr :=
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e.find? $ fun e => match e with
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| Expr.const c _ _ => c == `g
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| _ => false
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#eval findTest $ mkBig 4
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#eval findTest $ replaceTest $ mkBig 4
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#eval findTest $ mkBig 128
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#eval findTest $ (replaceTest $ mkBig 128)
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