in reply to printing LAST_MATCH_START/@- LAST_MATCH_END/@+ array where regex match begin/end

Move the match with /g into a condition of a while loop.

As there are no capture groups in the regex (i.e. no parentheses), using any other index than 0 makes no sense. Under warnings, you'd even get lots of Use of uninitialized value in print.

Moreover, when there's no match, the @- and @+ arrays are empty, there's no -1 (that's what index does). You have to handle that case yourself.

This should work directly as shown and output the expected output:

#!/usr/bin/perl use strict; use warnings; my $string = << "__EOS__"; foo bar baz foo bar foo\tbaz ccc ddd foo bar foo\tbaz ccc ddd\tfoo\tbar\tbaz foo bar foo\t\tbaz ccc ddd\t\t\tfoo __EOS__ open my $F0, '<', \$string or die $!; while (<$F0>) { my $match; while (/\t+/g) { $match = 1; print $-[0], ' ', $+[0], ' '; } print '-1 -1' unless $match; print "\n"; }

map{substr$_->[0],$_->[1]||0,1}[\*||{},3],[[]],[ref qr-1,-,-1],[{}],[sub{}^*ARGV,3]