Assistance in understanding syntax

Question

I am having trouble understanding the following:

@on_fallback = on_fallback || (->(_,  _){})

Could anybody please assist me in understanding the code that executes after the disjunciton operator?

Answer 1

It is a lambda that takes two block arguments and returns nil when executed.

When _ is used in an argument position of a method definition, lambda, or block, it indicates an argument that is not to be used in its scope. Unlike other argument names, _ can appear multiple times in a scope.