class Object

Stringish.new.acts_like?(:string) # => true

Then client code can query for duck-type-safeness this way:

end
end
def acts_like_string?
class Stringish

This class may define:

==== Example: A class that provides the same interface as String

value are irrelevant.
Note that the marker method is only expected to exist. It isn't called, so its body or return

method to interoperate.
and classes that are able to act like Time can also define an acts_like_time?
x.acts_like?(:time) and x.acts_like?(:date) to test duck-type compatibility,
and extends Time to define acts_like_time?. As a result, developers can call
For example, Active Support extends Date to define an acts_like_date? method,

acts_like?(:some_class).
acts_like_some_class? to signal its compatibility to callers of
A class that provides the same interface as SomeClass may define a marker method named

an appropriately-named marker method.
Provides a way to check whether some class acts like some other class based on the existence of

def acts_like?(duck)
  case duck
  when :time
    respond_to? :acts_like_time?
  when :date
    respond_to? :acts_like_date?
  when :string
    respond_to? :acts_like_string?
  else
    respond_to? :"acts_like_#{duck}?"
  end
end