How to call a function that mutates a variable in Ruby?

Question

The standard method would be something like

foo = bar(foo)

But I'd like some kind of way to simply write

bar(foo)

That would change the value of foo like the first line. In C++ I could do this with pointers, but with Ruby I don't know how to.

Answer 1

This is not possible in Ruby. You'll have to write foo = bar(foo).

Another option would be to let foo be a mutable object. Then bar could call methods on it to mutate it. For example, if foo is a String, Hash, or Array, bar could call foo.replace to modify the object that foo refers to.

Answer 2

这是不可能的。您正在寻找的是某种形式的传递参考。但是，Ruby是严格按值传递的。