Question

In Perl regex, how can I break from /ge loop..?

Let’s say the code is:

 s/\G(foo)(bar)(;|$)/{ break if $3 ne ';'; print "$1\n"; '' }/ge;

…break here doesn’t work, but it should illustrate what I mean.

Answer 1

Generally, I would write this as a while statement:

while( s/(foo)(bar)/$1/ ) {
    # my code to determine if I should stop
    if(something) {
        last;
    }
}

The caveat with this method is that your search/replace will start at the beginning each time, which may matter depending on your regex.

If you really wanted to do it in the regex, you could write a function that returns an unmodified string if you reached your end point, such as a count in this case:

my $count=0;

sub myfunc {
    my ($string, $a, $b) = @_;

    $count++;

    if($count > 3) {
        return $string;
    }

    return $a;
}

$mystring = "foobar  foobar, foobar + foobar and foobar";
$mystring =~ s/((foo)(bar))/myfunc($1,$2,$3)/ge;

# result: $mystring => "foo  foo, foo + foobar and foobar"

If I knew your specific case, I could probably provide a more helpful example.