After all of the bugs, updates, and general messiness caused by this question, I started wondering if using split was really the right way to go. It can be done with a regex:

my @tests = ( '', qw(
    2|3|||||
    2
    2|
    2|3
    2|3|
    |
    |2
    |2|
    |2|3
    |2|3|
));


for my $string (@tests) {

    # Splits on '|' and preserves empty fields...
    my @fields = $string =~ m/((?:^|(?<=\|))[^|]*)/g;

    printf "%-10s :", "'$string'";
    print "($_)" for @fields;
    print "\n";
}
__END__
''         :()
'2|3|||||' :(2)(3)()()()()()
'2'        :(2)
'2|'       :(2)()
'2|3'      :(2)(3)
'2|3|'     :(2)(3)()
'|'        :()()
'|2'       :()(2)
'|2|'      :()(2)()
'|2|3'     :()(2)(3)
'|2|3|'    :()(2)(3)()
[download]

However, constructing that regex wasn't particularly easy. I think, had I been faced with this task myself, I would have opted for the method you suggested. That is, append a non-empty field and then pop it off of the array after you split. At first it seems kind of a dirty trick but once you find how difficult it is to do it otherwise,

    my @fields = split /\|/, $string.'|x'; pop @fields;
[download]

starts looking more and more elegant. I imagine it would score well on efficiency too.

-sauoq
"My two cents aren't worth a dime.";