Adventures in Ignorance: when both Perl and the Developer are too smart for their own good.

So, split returns the number of fields it would have split into when called in scalar context, but it also throws a warning in Perl 5.10: "Use of implicit split to @_ is deprecated". In an attempt to placate the warning I wrote

my $count =()= split $delim, $string;

but was surprised to find that every string returned 1. This is due to a nice little optimization that split does for you:

When assigning to a list, if LIMIT is omitted, or zero, Perl
supplies a LIMIT one larger than the number of variables in the
list, to avoid unnecessary work. For the list above LIMIT
would have been 4 by default. In time critical applications it
behooves you not to split into more fields than you really
need.

To get around this you must specify your own limit of -1:

my $count =()= split $delim, $string, -1;

Of course, -1 doesn't have the same behavior as no limit or a limit of 0 (a limit of -1 preserves empty trailing fields), so this is not necessarily what you want. This leaves us with the last line of defense, turning off warnings (and it isn't pretty):

my $count = do {
        no warnings "deprecated";
        split $delim, $second;
};