Ruby include and extend

Ruby provides a powerful Inheritance Mechanism, and there are many inheritance methods. The simplest is"

Module Foo def Foo puts 'heyyyyoooo! 'Endclass Bar include fooendbar. New. Foo # heyyyyoooo! Bar. Foo # nomethoderror: Undefined method 'foo' for bar: classclass Baz extend fooendbaz. Foo # heyyyyoooo! Baz. New. Foo # nomethoderror: Undefined method 'foo' for # <0x1e708>

 

We can see that some instance methods are added for the target class through include. On the contrary, the extension adds corresponding class methods to the target class. Although it is a module, different methods will produce different results.