Ruby + =重载(Ruby += overloading)

Ruby + =重载(Ruby += overloading)

这有什么问题？

class Vec2 attr_accessor :x, :y # ... def += (v) @x += v.x @y += v.y return self end # ... end

我一直无法在网上找到很多。 有人说这是因为+ =在ruby中完成了调用+然后=，他在开玩笑吧？

在有趣的情况下，他是对的，是否有一些解决方法（除了定义一个名为“add”的方法）？

What is wrong with this?

class Vec2 attr_accessor :x, :y # ... def += (v) @x += v.x @y += v.y return self end # ... end

I've not been able to find much online. Someone said it is because += in ruby is done calling + and then =, he was kidding right?

In the amusing case he was right, is there some workaround (aside from defining a method called "add")?

最满意答案

有人说这是因为+ =在ruby中完成了调用+然后=，他在开玩笑吧？

不，他是对的（除了“calling =”有点不准确，因为=不是方法）。

有没有一些解决方法（除了定义一个名为“add”的方法）？

你的意思不是定义+而是以+=会改变变量而不是对象为由的事实？

你可以改变+来改变对象，然后返回self ，在这种情况下， v1 += v2将与v1 + v2相同，并会改变对象。 然而，我强烈建议反对，因为没有人会期望+变异（类似地，大多数有红宝书意识的人会希望+=重新分配变量而不改变对象，所以试图改变它可能完全不可取）。

除此之外，不，没有办法解决这个问题。

Someone said it is because += in ruby is done calling + and then =, he was kidding right?

No, he is right (except that "calling =" is a bit inaccurate as = is not a method).

is there some workaround (aside from defining a method called "add")?

You mean other than defining + and living with the fact that += will change the variable and not the object?

You could change + to mutate the object and then return self, in which case v1 += v2 would be the same as v1 + v2 and would mutate the object. However I'd strongly advise against that as no one would expect + to be mutating (similarly most ruby-literate people would expect += to reassign the variable and not mutate the object, so trying to change that might just be inadvisable altogether).

Other than that, no, there's no way to work around this.