class 继承了相同 class 的两个不同的泛型派生

Question

通过继承确定可迭代类型的正确方法是什么。

不允许继承 FOO[如 babar]

FOO

class FOO

inherit
    ITERABLE[detachable ANY] -- I know garbage but for DB_RESULT its the case


feature -- Access

    new_cursor: ITERATION_CURSOR[like items.item]
        do
            Result := items.new_cursor
        end

    items: ARRAY[detachable ANY]


end -- class FOO

酒吧

class BAR

inherit
    FOO -- I know garbage but for DB_RESULT its the case

    ITERABLE[STRING] -- I know garbage but for DB_RESULT its the case


feature -- Access

    new_cursor: ITERATION_CURSOR[like items.item]
        do
            Result := items.new_cursor
        end

    items: ARRAY[STRING]


end -- class FOO

Answer 1

我建议在 class FOO:

中使用正式的泛型参数

class FOO [G]
inherit
    ITERABLE [G]

然后，class BAR 将提供一个合适的实际泛型参数：

class BAR
inherit
    FOO [STRING]

class 继承了相同 class 的两个不同的泛型派生

The class inherits two different generic derivations of the same class

generics

polymorphism

eiffel

generic-collections

FOO

酒吧