use warnings;
use strict;
use feature 'say';
for my $m (map {"File::Spec::$_"} qw/Unix Win32 Mac OS2
        VMS Cygwin Epoc/) {
    say "##### $m #####";
    eval qq{ use $m; 1 } or warn "Skipping $m because: $@" and next;
    say "        catdir: ", $m->catdir("foo","bar");
    #say "  catdir undef: ", $m->catdir("foo","bar",undef); # warns
    say "  catdir blank: ", $m->catdir("foo","bar","");
    say " catdir curdir: ", $m->catdir("foo","bar",$m->curdir);
    #say " catfile undef: ", $m->catfile("foo","bar",undef); # warns
    say " catfile blank: ", $m->catfile("foo","bar","");
    say "catfile curdir: ", $m->catfile("foo","bar",$m->curdir);
    say " catpath undef: ", $m->catpath(undef,"foo",undef);
    say " catpath blank: ", $m->catpath(undef,"foo","");
    say "catpath curdir: ", $m->catpath(undef,"foo",$m->curdir);
}
__END__
##### File::Spec::Unix #####
        catdir: foo/bar
  catdir blank: foo/bar
 catdir curdir: foo/bar
 catfile blank: foo/bar/
catfile curdir: foo/bar/.
 catpath undef: foo
 catpath blank: foo
catpath curdir: foo/.
##### File::Spec::Win32 #####
        catdir: foo\bar
  catdir blank: foo\bar
 catdir curdir: foo\bar
 catfile blank: foo\bar
catfile curdir: foo\bar
 catpath undef: foo
 catpath blank: foo
catpath curdir: foo\.
##### File::Spec::Mac #####
        catdir: :foo:bar:
  catdir blank: :foo:bar:
 catdir curdir: :foo:bar:
 catfile blank: :foo:bar:
catfile curdir: :foo:bar:
 catpath undef: :foo:
 catpath blank: :foo:
catpath curdir: :foo:
##### File::Spec::OS2 #####
        catdir: foo/bar
  catdir blank: foo/bar
 catdir curdir: foo/bar
 catfile blank: foo/bar/
catfile curdir: foo/bar/.
 catpath undef: foo
 catpath blank: foo
catpath curdir: foo/.
##### File::Spec::VMS #####
Skipping File::Spec::VMS because: Can't locate VMS/Filespec.pm in @INC
##### File::Spec::Cygwin #####
        catdir: foo/bar
  catdir blank: foo/bar
 catdir curdir: foo/bar
 catfile blank: foo/bar/
catfile curdir: foo/bar/.
 catpath undef: foo
 catpath blank: foo
catpath curdir: foo/.
##### File::Spec::Epoc #####
        catdir: foo/bar
  catdir blank: foo/bar
 catdir curdir: foo/bar
 catfile blank: foo/bar/
catfile curdir: foo/bar/.
 catpath undef: foo
 catpath blank: foo
catpath curdir: foo/.