Interesting question! I'd say that unless all of your return statements take some form of return $one, $two, $three;, that's something you could only do at runtime instead of by looking at the source, as it gets less clear how many values will actually be returned in situations like return @foo; or return bar();.

How about something like Hook::LexWrap (see also http://www.perladvent.org/2003/3rd/)? I haven't really used it before but it seems like it should be possible to implement a check like you want:

use Hook::LexWrap 'wrap';
sub my_func { return ("foo") x shift }
wrap my_func =>
    post => sub {
        my $cnt = @{$_[-1]}; # assumes list context!
        print "Returning $cnt values\n";
    };
print my_func(1), "\n";
print my_func(2), "\n";
print my_func(3), "\n";
__END__
Returning 1 values
foo
Returning 2 values
foofoo
Returning 3 values
foofoofoo

[download]

It may also be worth taking a step back: How many returns do you have per sub? What's the largest number of values per return you have? If you've got a lot of returns per sub, then perhaps your logic is getting a little too complex? And if you have a large number of values per return, then perhaps you could look into returning complex data structures instead, like arrayrefs, hashrefs, or objects?

In reply to Re: Checking number of values returned by Anonymous Monk
in thread Checking number of values returned by jfrm

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