This is I think a good combination of cheap and simple for use in a more functional style of ruby.
Very simple cases
class AddOne
singleton_class.attr_accessor :to_proc
self.to_proc = ->(x) { x + 1 }
define_singleton_method(:call, to_proc)
end
1.then(&AddOne) #=> 2
AddOne.call(1) #=> 2
More complex cases
Most times you will want to use Object instances as they make refactoring easier.
class AddTwo
singleton_class.attr_accessor :to_proc
self.to_proc = ->(x) { new(x).call }
define_singleton_method(:call, to_proc)
def initialize(x)
@x = x
end
def call
@x + 2
end
end
1.then(&AddTwo) #=> 3
AddTwo.call(1) #=> 3
edit: changed class << self to singleton_class