Scope Resolution Operator - Ruby

Ruby

In Ruby, scope resolution can be specified using namespaces (such as classes or modules).

module Example Version = 1.0 class << self # We are accessing the Module's singleton class def hello(who = "World") "hello #{who}" end end end #/Example Example::hello # => "hello World" Example.hello "hacker" # => "hello hacker" Example::Version # => 1.0 Example.Version # NoMethodError # This illustrates the difference between the message (.) operator and the scope operator in Ruby (::) # We can use both ::hello and .hello, because hello is a part of Example's scope and because Example # responds to the message hello. # # We can't do the same with ::Version and .Version, because Version is within the scope of Example, but # Example can't respond to the message Version, since there is no method to respond with.