What does this Ruby syntax mean: if self < Class::Name?

Question

I came across this strange syntax I have never seen before:

if self < Example::Class::Name
  # do something
else
  # do something else
end

What does this check?

score 4 · Accepted Answer · answered Jan 10 '14 at 00:31

4

It checks if self is a subclass of Example::Class::Name

Check out the Module docs :)

answered Jan 10 '14 at 00:31

Ju Liu

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18

score 2 · Answer 2 · edited May 23 '17 at 12:21

Superclass / Sub-class check.

This is checking if Example::Class::Name is the superclass of self by this sort of declaration:

class DemonstrationClass < Example::Class::Name
  #de body of sub-class

  def cascade *parameters
     #de ...do work
     super #de passes all parameters to the same method name of the super-class.
           #de this even works on an initialize method declaration!
  end
end

Instances of DemonstrationClass are sub-classes of the Example::Class::Name super class.

Sub-classes have the special feature of being able do things like what I showed in the cascade method, and many more things.

Related questions with more sample code, and examples of associated concepts involved:

What does this Ruby syntax mean: if self < Class::Name?

2 Answers2

Superclass / Sub-class check.