Topic: type inheritance as reuse

topics > computer science > programming > object-oriented programming > Group: type inheritance

inheritance by delegation
inheritance of properties
restricted and extended types
reusable programming
type conversion
type hierarchy


Sub-classes can redefine an inherited attribute. This allows common procedures to move up in the hierarchy despite exceptions and it allows the definition of class templates. (cbb 1/90)

With type inheritance, you can reuse a class's methods and/or properties by extension or refinement. This allows different objects to share methods without copying. (cbb 3/01)

Subtopic: inheritance as reuse up

Quote: object-oriented inheritance allows the extension and refinement of existing code without modifying the code. This is the essence of inheritance [»taivA9_1996]
Quote: inheritance allows the creation of a new class from existing classes; i.e., incremental program development [»taivA9_1996]
Quote: inheritance with late binding, self-reference, and super-reference allows objects to be reused without textual copying or editing; a new way to write programs [»taivA9_1996]
Quote: use inheritance of attributes and constraints to abbreviate descriptions [»borgA1_1985]
Quote: inheritance allows for polymorphic variables to become attached at run-time [»meyeB9_1990]
Quote: complete source listings for Smalltalk is only four inches thick; perhaps due to inheritance [»coxBJ7_1983]

Subtopic: inheritance as sharing up

Quote: inclusion polymorphism--operations on a given type are applicable to all subtypes; via inheritance
Quote: type inheritance describes common features while strong typing erects fire walls between types [»wolfW9_1989]
Quote: inheritance is synonymous with receiving; the parent and descendent share something with each other [»taivA9_1996]
Quote: inheritance allows different objects to share methods without copying them
Quote: Smalltalk class variables are shared by the class and all its instances [»xlrg8_1981]

Subtopic: inheritance of interface up

Quote: with object-orientation, a new observation must be added to each class; inheritance helps

Subtopic: inheritance by subtype up

Quote: Pegasus functions on a given type are defined for all of its subtypes; objects are instances of a type and all of its supertypes
Quote: adding sort to the class OrderedCollection defines sort for all objects in that class or its sub-classes [»ingaDH8_1981a]
Quote: a subtype inherits the properties and facts of its parent type [»kentW1_1984]
Quote: in object-oriented programs, inheritance means that the same compiled code is shared by descendents [»taivA9_1996]
Quote: an Ada derived type defines a new type which inherits all operations and attributes of its base type [»maclBJ_1987]
Quote: a Smalltalk subclass inherits the instance variables and methods of its superclass [»xlrg8_1981]
Quote: object classes organized in a hierarchy with inheritance of constraints [»borgA10_1986]

Subtopic: inheritance as extension up

Quote: object-oriented inheritance is an extension mechanism, not a specialization or classification mechanism [»winkJF8_1992]
Quote: in Simula, can extend a class by appending information [»palmJ5_1973, OK]
QuoteRef: goldA3_1976 ;;18 can append to a class definition
Quote: a declared instance of a class is expanded into the variables recursively specified by the class's memory [»hendP9_1975]
Quote: inheritance is record combination; the record for a new class is like its parent's record, but extended with new properties [»taivA9_1996]

Subtopic: modified inheritancer up

Quote: characterize Eiffel inheritance by "is-plus-but-except"; instance of parent with new, hidden or changed features and changed type signatures [»meyeB9_1990]
Quote: a redefined Eiffel feature must include an equal or weaker precondition and an equal or stronger postcondition; satisfies contract [»meyeB9_1990]
Quote: if redeclare an inherited routine, can weaken its precondition or strengthen its postcondition [»meyeB10_1992]

Related Topics up

Topic: inheritance by delegation (8 items)
Topic: inheritance of properties (24 items)
Topic: restricted and extended types (35 items)
Topic: reusable programming (77 items)
Topic: type conversion (33 items)
Topic: type hierarchy
(18 items)

Updated barberCB 3/05
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Thesa is a trademark of C. Bradford Barber.