init.p6

# initialize a new allegro-pascal project

my $projectname = "newproject"; 
my $allegropas-src = "allegro.pas-5.2.a3-src-pas/lib";

if $projectname.IO.e {
	say "project $projectname already exists";
} else {
	mkdir $projectname or die "$!";
	try {
		CATCH {
			rmdir $projectname;
			die "$_!";
		}
		my @filelist = dir $allegropas-src;
		for @filelist {
			my $relpath = $_.relative($allegropas-src);
			copy $_, $projectname.IO.add($relpath);
		}
		say "created project $projectname";
	}
}

There is no need for or die "$!" as that is what happens when mkdir is in sink context.