smalltalk - subclassResponsibility sender selector stuck -

subclassResponsibility The sender selector is still stuck when the subclasses method is applied.

I think logic may be the reason but what is this?

And nobody can tell us why?

In the abstract class, we get it from

  string: string "inst string with" ^ self subclassResponsibility   
 and I run it I'm having:  
  unit: = (a new unit by string: aString)   
 Then the error occurs.  
 The current approach of Travis Griggs can still remove the error  
 Is there bilateral example creation method?   
 
 
 There shy on details, but it seems that it is doing precisely what you have Told.  
 Expression  Units new  returned a new  unit  and then you sent the string from  to: . Which you have implemented to return the result of sending  subclassResponsibility .  
 If the  units  is actually a  abstract element  class, I will not expect to instantiate it (unless you have  new < / Code> are not messed up with you until you send  new  to abstract classes).  
 That is why I would expect you to do something like this:  
  unit: = (string with your realshobs new: aString)   
 And that is a real implementation of  YourRealSubclass  from  to string: