The problem with this is that the numeric comparison could return false positives. Try doing a comparison of 'aa' == 'bb'. With -w on, this does issue warnings, however it will still return true.
That is why something like Fletcher's looks_like_number from Scalar::Util is needed.
I have not used it myself, so I can not attest to the accuracy of this function, however the code would be like this:
sub equals {
my ($val1,$val2) = @_;
return 1 if !defined $val1 && !defined $val2;
if (looks_like_number($val1) && looks_like_number($val2)) {
return $val1 == $val2;
} else {
return $val1 eq $val2;
}
}