undo some instructions
Major Section: PROOF-CHECKER-COMMANDS
Examples: (undo 7) undoNote: To remove the effect of an
(undo n) -- Undo the last n instructions. The argument n should be a positive integer.
undo -- Same as (undo 1).
restore. See the documentation for details.
Note: If the argument
n is greater than the total number of
interactive instructions in the current session, then
(undo n) will
simply take you back to the start of the session.
undo meta command always ``succeeds''; it returns
(mv nil t state) unless its optional argument is supplied and of
the wrong type (i.e. not a positive integer) or there are no
instructions to undo.