eval.c:1361
int
ruby_exec()
{
    int state;
    volatile NODE *tmp;

    Init_stack((void*)&tmp);
    PUSH_TAG(PROT_NONE);
    PUSH_ITER(ITER_NOT);
    /* default visibility is private at toplevel */
    SCOPE_SET(SCOPE_PRIVATE);
    if ((state = EXEC_TAG()) == 0) {
	eval_node(ruby_top_self, ruby_eval_tree);
    }
    POP_ITER();
    POP_TAG();
    return state;
}
