static public AST_Tree NewInterimChild(this AST_Tree self) { var c = new AST_Interim(); self.AddChild(c); return(c); }
static public void AddChildren(this AST_Tree self, IAST b) { if (b is AST_Tree c) { for (int i = 0; i < c.children.Count; ++i) { self.AddChild(c.children[i]); } } }