lean4-htt/src/Lean/Meta/Tactic/Simp/BuiltinSimprocs/Util.lean
2024-02-18 14:55:17 -08:00

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/-
Copyright (c) 2024 Amazon.com, Inc. or its affiliates. All Rights Reserved.
Released under Apache 2.0 license as described in the file LICENSE.
Authors: Leonardo de Moura
-/
prelude
import Lean.Meta.Tactic.Simp.Simproc
namespace Lean.Meta.Simp
/--
Let `result` be the result of evaluating proposition `p`, return a `.done` step where
the resulting expression is `True`(`False`) if `result is `true`(`false`), and the
proof is uses `Decidable p` and the auxiliary theorems `eq_true_of_decide`/`eq_false_of_decide`.
-/
def evalPropStep (p : Expr) (result : Bool) : SimpM Step := do
let d ← mkDecide p
if result then
return .done { expr := mkConst ``True, proof? := mkAppN (mkConst ``eq_true_of_decide) #[p, d.appArg!, (← mkEqRefl (mkConst ``true))] }
else
return .done { expr := mkConst ``False, proof? := mkAppN (mkConst ``eq_false_of_decide) #[p, d.appArg!, (← mkEqRefl (mkConst ``false))] }
end Lean.Meta.Simp