lean4-htt/src/Lean/Meta/KAbstract.lean
2020-06-25 11:21:17 -07:00

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/-
Copyright (c) 2020 Microsoft Corporation. All rights reserved.
Released under Apache 2.0 license as described in the file LICENSE.
Author: Leonardo de Moura
-/
import Lean.Data.Occurrences
import Lean.HeadIndex
import Lean.Meta.ExprDefEq
namespace Lean
namespace Meta
private partial def kabstractAux (occs : Occurrences) (p : Expr) (pHeadIdx : HeadIndex) (pNumArgs : Nat) : Expr → Nat → StateT Nat MetaM Expr
| e, offset =>
let visitChildren : Unit → StateT Nat MetaM Expr := fun _ =>
match e with
| Expr.app f a _ => do f ← kabstractAux f offset; a ← kabstractAux a offset; pure $ e.updateApp! f a
| Expr.mdata _ b _ => do b ← kabstractAux b offset; pure $ e.updateMData! b
| Expr.proj _ _ b _ => do b ← kabstractAux b offset; pure $ e.updateProj! b
| Expr.letE _ t v b _ => do t ← kabstractAux t offset; v ← kabstractAux v offset; b ← kabstractAux b (offset+1); pure $ e.updateLet! t v b
| Expr.lam _ d b _ => do d ← kabstractAux d offset; b ← kabstractAux b (offset+1); pure $ e.updateLambdaE! d b
| Expr.forallE _ d b _ => do d ← kabstractAux d offset; b ← kabstractAux b (offset+1); pure $ e.updateForallE! d b
| e => pure e;
if e.hasLooseBVars then visitChildren ()
else if e.toHeadIndex == pHeadIdx && e.headNumArgs == pNumArgs then
condM (liftM $ isDefEq e p)
(do i ← get;
set (i+1);
if occs.contains i then
pure (mkBVar offset)
else
visitChildren ())
(visitChildren ())
else
visitChildren ()
def kabstract (e : Expr) (p : Expr) (occs : Occurrences := Occurrences.all) : MetaM Expr :=
(kabstractAux occs p p.toHeadIndex p.headNumArgs e 0).run' 1
end Meta
end Lean