74 lines
2.2 KiB
Text
74 lines
2.2 KiB
Text
/-
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Copyright (c) 2020 Microsoft Corporation. All rights reserved.
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Released under Apache 2.0 license as described in the file LICENSE.
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Authors: Leonardo de Moura
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-/
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prelude
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import Lean.Expr
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namespace Lean
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namespace CollectLevelParams
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structure State where
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visitedLevel : LevelSet := {}
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visitedExpr : ExprSet := {}
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params : Array Name := #[]
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instance : Inhabited State := ⟨{}⟩
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abbrev Visitor := State → State
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mutual
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partial def visitLevel (u : Level) : Visitor := fun s =>
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if !u.hasParam || s.visitedLevel.contains u then s
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else collect u { s with visitedLevel := s.visitedLevel.insert u }
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partial def collect : Level → Visitor
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| .succ v => visitLevel v
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| .max u v => visitLevel v ∘ visitLevel u
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| .imax u v => visitLevel v ∘ visitLevel u
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| .param n => fun s => { s with params := s.params.push n }
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| _ => id
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end
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def visitLevels (us : List Level) : Visitor :=
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fun s => us.foldl (fun s u => visitLevel u s) s
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mutual
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partial def visitExpr (e : Expr) : Visitor := fun s =>
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if !e.hasLevelParam then s
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else if s.visitedExpr.contains e then s
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else main e { s with visitedExpr := s.visitedExpr.insert e }
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partial def main : Expr → Visitor
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| .proj _ _ s => visitExpr s
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| .forallE _ d b _ => visitExpr b ∘ visitExpr d
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| .lam _ d b _ => visitExpr b ∘ visitExpr d
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| .letE _ t v b _ => visitExpr b ∘ visitExpr v ∘ visitExpr t
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| .app f a => visitExpr a ∘ visitExpr f
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| .mdata _ b => visitExpr b
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| .const _ us => visitLevels us
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| .sort u => visitLevel u
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| _ => id
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end
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partial def State.getUnusedLevelParam (s : CollectLevelParams.State) (pre : Name := `v) : Level :=
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let v := mkLevelParam pre;
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if s.visitedLevel.contains v then
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let rec loop (i : Nat) :=
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let v := mkLevelParam (pre.appendIndexAfter i);
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if s.visitedLevel.contains v then loop (i+1) else v
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loop 1
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else
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v
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end CollectLevelParams
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def collectLevelParams (s : CollectLevelParams.State) (e : Expr) : CollectLevelParams.State :=
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CollectLevelParams.main e s
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def CollectLevelParams.State.collect (s : CollectLevelParams.State) (e : Expr) : CollectLevelParams.State :=
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collectLevelParams s e
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end Lean
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