Commit 0505dc66 authored by Robbert Krebbers's avatar Robbert Krebbers
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Type-class based conditional `TCIf P Q R` that does not backtrack on `P`.

parent 680e10eb
......@@ -5,6 +5,21 @@ From iris.base_logic Require Import big_op tactics.
Set Default Proof Using "Type".
Import uPred.
(* FIXME: Move to stdpp *)
(* A conditional at the type class level. Note that [TCIf P Q R] is not the same
as [TCOr (TCAnd P Q) R]: the latter will backtrack to [R] if it fails to
establish [R], i.e. does not have the behavior of a conditional. Furthermore,
note that [TCOr (TCAnd P Q) (TCAnd (TCNot P) R)] would not work; we generally
would not be able to proof the negation of [P]. *)
Inductive TCIf (P Q R : Prop) :=
| TCIf_true : P Q TCIf P Q R
| TCIf_false : R TCIf P Q R.
Existing Class TCIf.
Hint Extern 0 (TCIf _ _ _) =>
first [apply TCIf_true; [apply _|]
|apply TCIf_false] : typeclass_instances.
Section classes.
Context {M : ucmraT}.
Implicit Types P Q R : uPred M.
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