What does -@ operator do in Ruby?

Question

I've found the -@ operator redefinition in Rails/ActiveSupport:

https://github.com/rails/rails/blob/master/activesupport/lib/active_support/duration.rb#L33

Can you tell me what does it mean?

Answer 1

-@ and +@ are simply the method names for unary - and +. If you want to redefine them, invoke them as methods, etc., that's how you need to refer to them to distinguish them from binary - and +.

Answer 2

I think it defines what happens when the object is negated, for example:

x = -y

The y object needs to have a -@ operator defined.