public static IEnumerable <PartialNode> Child(PartialNode tree) => tree.Yield();
public static IEnumerable <PartialNode> Children(PartialNode head, IEnumerable <PartialNode> tail) => head.Yield().Concat(tail);
public static SyntaxNode New(PartialNode tree) { var context = new SyntaxNodeContext(); return(tree.Instantiate(context, 0)); }