is there one-liner shortcut for `class << self def isogram? # code here end end` in ruby

Yes, there is a one-liner shortcut for defining class methods in Ruby using the class << self syntax. Here's the equivalent one-liner shortcut for your code:

main.rb
def self.isogram?; end
23 chars
2 lines

This one-liner defines the class method isogram? on the current class.

Here's an example of how you can use it:

main.rb
class MyClass
  def self.isogram?
    # code here
  end
end
60 chars
6 lines

The above example can be rewritten using the one-liner syntax:

main.rb
class MyClass
  def self.isogram?; end
end
43 chars
4 lines

Note that the one-liner syntax is generally used for defining simple class methods without any implementation code. If you need to add implementation code to the method, it's recommended to use the multiline class << self syntax for better readability.