#!/usr/bin/perl
use strict;
use warnings;

my $RefLine = "(a) This is first line(once all 4 was one line). (b) This is second line; (
print "original -----\n";
print "$RefLine\n";
print "original -----\n\n";

print "\n## without 'end of line or' condtion. last line fails\n";
while( $RefLine =~ /(\([a-z]\).*?)(?=\([a-z]\))/g ){
    my $p=pos $RefLine;
    print "$-[0], $p,matched=$&\n";
    print "---\n";
}

print "\n## without lookahead assertion... \n";
while( $RefLine =~ /(\([a-z]\).*?)($|\([a-z]\))/g ){
    my $p=pos $RefLine;
    print "$-[0], $p,matched=$&\n";
    print "---\n";
}

print "\n## with 'end of line or' condtion and zero width place holder\n";
while( $RefLine =~ /(\([a-z]\).*?)(?=$|\([a-z]\))/g ){
    my $p=pos $RefLine;
    print "$-[0], $p,matched=$&\n";
    print "---\n";
}