remove the effect of an UNDO command
Major Section: PROOF-CHECKER-COMMANDS
Example and General Form: restore
Restore
removes the effect of an undo
command. This always works as
expected if restore
is invoked immediately after undo
, without
intervening instructions. However, other commands may also interact
with restore
, notably ``sequencing'' commands such as do-all
,
do-strict
, protect
, and more generally, sequence
.
Note: Another way to control the saving of proof-checker state is
with the save
command; see the documentation for save
.
The restore
command always ``succeeds''; it returns
(mv nil t state)
.