ast_new
AstNode* ast_new(AstNode *parent, int index, const char *prefix, void *ptr, void (*expand)(AstNode*));
AstNode *child = ast_new(parent, parent->childnodes->len,
AstNode *child = ast_new(parent, parent->childnodes->len, text, NULL, NULL);
root = ast_new(NULL, 0, "", ptr, inspect_symbol_list);