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.

Suggestions:

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

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

In reply to Re: Refer by relative way to regex group (eg. the last one) by Anonymous Monk
in thread Refer by relative way to regex group (eg. the last one) by Anonymous Monk

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