埃菲爾鐵塔（Eiffel）：附加到check語句中的未知標識符

Question

    require
        valid_item: attached item as l_i and then l_i.valid_for_insert or l_i.valid_for_update

為什么我的l_i有一個未知的標識符？

Answer 1

試試看

valid_item: attached item as l_i and then (l_i.valid_for_insert or l_i.valid_for_update)

請注意，您也可以

item_set: attached item as l_i 
valid_item: l_i.valid_for_insert or l_i.valid_for_update

您可以從先前的前提中重用對象測試局部變量l_i 。