Getopt::Long has a configration option called 'gnu_compat' which I thought might work, but...
gnu_compat
gnu_compat controls whether --opt= is allowed, and what it should do. Without gnu_compat, --opt= gives an error. With gnu_compat, --opt= will give option opt and empty value. This is the way GNU getopt_long() does it.
Note that --opt value is still accepted, even though GNU getopt_long() doesn't.
Your problem is that note at the end. You do not want "--opt value" to be accepted, you want it to behave like "--opt= nextarg".
In the source for Getopt::Long there is this code to handle gnu_compat:
# Check if there is an option argument available.
if ( $gnu_compat ) {
my $optargtype = 0; # none, 1 = empty, 2 = nonempty, 3 = aux
--cut--
elsif ( defined $rest || @$argv > 0 ) {
# GNU getopt_long() does not accept the (optional)
# argument to be passed to the option without = sign.
# We do, since not doing so breaks existing scripts.
$optargtype = 3;
}
--cut--
return (1, $opt, $ctl, $type eq 's' ? '' : 0)
if $optargtype == 1; # --foo= -> return nothing
}
I think if you set '$optargtype' to 1 here it would work.
Maybe Getopt::Long could add a configuration option called 'gnu_compat_strict' so you could have:
elsif ( defined $rest || @$argv > 0 ) {
$optargtype = $gnu_compat_strict ? 1 : 3;
}