#!/usr/bin/perl -wl
use strict;

sub msplit {
    my ($delim, $str) = @_;
    my $pat = '';
    $pat = "(?>(.*?)$_$pat)?" for reverse @$delim;
    grep defined, $str =~ /^$pat(.+)/;
}

print for map "'$_'", msplit [qw(: :: \s+)], "a:b::c  d";
__END__
'a'
'b'
'c'
'd'