lean4-htt/src/Lean/Elab/Tactic/Cache.lean
Leonardo de Moura 92382ea47b fix: checkpoint
2022-04-01 05:53:18 -07:00

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/-
Copyright (c) 2022 Microsoft Corporation. All rights reserved.
Released under Apache 2.0 license as described in the file LICENSE.
Authors: Leonardo de Moura
-/
import Lean.Elab.Tactic.Basic
namespace Lean.Elab.Tactic
open Meta
private def equivMVarDecl (d₁ d₂ : MetavarDecl) : Bool :=
d₁.type == d₂.type &&
d₁.lctx.decls.size == d₂.lctx.decls.size &&
Id.run do
for i in [:d₁.lctx.decls.size] do
match d₁.lctx.decls[i], d₂.lctx.decls[i] with
| some localDecl₁, some localDecl₂ => if localDecl₁.type != localDecl₂.type then return false
| none, none => pure ()
| _, _ => return false
return true
private def findCache? (cacheRef : IO.Ref Cache) (mvarId : MVarId) (stx : Syntax) : TacticM (Option Snapshot) := do
let some s := (← cacheRef.get).pre.find? mvarId | return none
let mvarDecl ← getMVarDecl mvarId
let some mvarDeclOld := s.meta.mctx.findDecl? mvarId | return none
if equivMVarDecl mvarDecl mvarDeclOld && stx == s.stx then
return some s
else
return none
@[builtinTactic checkpoint] def evalCheckpoint : Tactic := fun stx =>
focus do
let some cacheRef := (← readThe Term.Context).tacticCache? | evalTactic stx[1]
let mvarId ← getMainGoal
match (← findCache? cacheRef mvarId stx[1]) with
| some s =>
cacheRef.modify fun { pre, post } => { pre, post := post.insert mvarId s }
set s.core
set s.meta
set s.term
set s.tactic
| none =>
evalTactic stx[1]
let s := {
stx := stx[1]
core := (← getThe Core.State)
meta := (← getThe Meta.State)
term := (← getThe Term.State)
tactic := (← get)
}
cacheRef.modify fun { pre, post } => { pre, post := post.insert mvarId s }
end Lean.Elab.Tactic