Ruby dynamic append class definition

Ruby is a dynamic language that allows you to change the class definition at any time. For example, if a class already exists when we define it, the definition at this time is to append the previous class, rather than re-define it.

 

Class Apple
Def show
Puts " One apple "
End
End
A = Apple. New ()
A. Show

ClassApple
# Append a test method to the Apple class
Def Test
Puts"Good taste"
End
End

A=Apple.New()
A. Show
A. Test

 

Use special classes to define append methods and variables for a certain object.

 

Class   < A
Def name
Puts " Fuji "
End
End

A. Show
A. Name

 

 

After a name method is appended to the special class defined as object A, A can call the name method, but other Apple instances still do not have the name method.