"A full package name, that is, a period-separated list of lowercase identifiers.
shared class FullPackageName(components)
        extends Node() {
    "The component names.
     (It is recommended that they contain only characters from the ASCII character set.)"
    shared [PackageName+] components;
    shared actual [PackageName+] children = components;
    shared actual Result transform<out Result>(Transformer<Result> transformer)
            => transformer.transformFullPackageName(this);
    shared actual void visit(Visitor visitor)
            => visitor.visitFullPackageName(this);
    shared actual Boolean equals(Object that) {
        if (is FullPackageName that) {
            return components == that.components;
        } else {
            return false;
    shared actual Integer hash
            => 31 * components.hash;
    shared FullPackageName copy([PackageName+] components = this.components) {
        value ret = FullPackageName(components);
        return ret;