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A comment on Alan Kay on the Meaning of “Object-Oriented Programming” (2003). Parent comment

Re:Alan Kay on the Meaning of “Object-Oriented Programming” ... by thewarrior on Sunday November 30, 2014 @11:35PM (#8679515)
How would you design something like :

Person --> Full Time Employee --> Manager

Person --> Contract Employee

Without inheritance assuming that salary calculation is the only thing which differentiates them.

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Re:Alan Kay on the Meaning of “Object-Oriented Programming” ... by derefr on Sunday November 30, 2014 @11:48PM (#8679549)
Something like...

   Person HAS A IEmploymentRelationship
   ContractEmployment IMPLEMENTS IEmploymentRelationship
   FullTimeEmployment IMPLEMENTS IEmploymentRelationship
   FullTimeEmployment HAS A IDirectReport
   Manager HAS A Person
   Manager IMPLEMENTS IDirectReport
And then salary() is a polymorphic function declared by the IEmploymentRelationship interface, where FullTimeEmployment instances use the manager somehow, and ContractEmployment doesn't.

You can even put some sugar on that by having a salary() function on Person that calls the salary() function on its IEmploymentRelationship—but I wouldn't, for the same reason I wouldn't denormalize a relational database.

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Re:Alan Kay on the Meaning of “Object-Oriented Programming” ... by thewarrior on Monday December 01, 2014 @12:04AM (#8679592)
Got it. Thank you.
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