in reply to Refer by relative way to regex group (eg. the last one)

You do not say how your code fails, but if you add use strict; to your example you get

$ perl -Mstrict -Mwarnings -e 'my $word; "foobar" =~ /(oo)(bar)(?{$word=${-1}})/'
Can't use string ("-1") as a SCALAR ref while "strict refs" in use at -e line 1.


$ perldoc -v '@-'
$ perldoc -v '@+'

Or, under at least Perl 5.10, you could use named captures.