- *
- * See the comments in S_clear_yystack() for more
- * details on the following three flags:
- *
- * op_latefree tell op_free() to clear this op (and free any kids)
- * but not yet deallocate the struct. This means that
- * the op may be safely op_free()d multiple times
- * op_latefreed an op_latefree op has been op_free()d
- * op_attached this op (sub)tree has been attached to a CV