38 lines
1.1 KiB
Text
38 lines
1.1 KiB
Text
import Lean
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open Lean
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def mkTower : Nat → Expr
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| 0 => mkConst `a
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| n+1 => mkApp2 (mkConst `f) (mkTower n) (mkTower n)
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partial def depth : Expr → MonadCacheT Expr Nat CoreM Nat
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| e =>
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checkCache e fun e =>
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match e with
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| Expr.const c [] _ => pure 1
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| Expr.app f a _ => do d₁ ← depth f; d₂ ← depth a; pure $ Nat.max d₁ d₂ + 1
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| _ => pure 0
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#eval (depth (mkTower 100)).run
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partial def visit : Expr → MonadCacheT Expr Expr CoreM Expr
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| e =>
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checkCache e fun e =>
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match e with
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| Expr.const `a [] _ => pure $ mkConst `b
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| Expr.app f a _ => e.updateApp! <$> visit f <*> visit a
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| _ => pure e
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#eval (visit (mkTower 4)).run
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#eval do e ← (visit (mkTower 100)).run; (depth e).run
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partial def visitNoCache : Expr → CoreM Expr
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| e =>
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match e with
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| Expr.const `a [] _ => pure $ mkConst `b
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| Expr.app f a _ => e.updateApp! <$> visitNoCache f <*> visitNoCache a
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| _ => pure e
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-- The following is super slow
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-- #eval do e ← visitNoCache (mkTower 30); (depth e).run
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