Endless Method Definition in Ruby

A new method definition was introduced in Ruby 3.0, the endless definition.

You're probably familiar with:

def do_something(number)
  number * 2
end

Of course, we can express this as a one-liner previously as:

def do_something(number); number * 2; end

Now you have the option to write it like this:

def do_something(number) = number * 2

Or another example:

def thing(x) = @thing = x

If you'd like to know more, here is where the spec was discussed