The last successful pattern that matched in the current scope. The empty pattern defaults to matching to this. For instance:
if (m/foo/ || m/bar/) {
s//BLAH/;
}
and
if (m/foo/ || m/bar/) {
s/${^LAST_SUCCESSFUL_PATTERN}/BLAH/;
}
are equivalent.
You can use this to debug which pattern matched last, or to match with it again.
Added in Perl 5.37.10.