Quote: design for inheritance or prohibit it; inheritance commits forever design decisions about usage, protected methods, and other aspects of a class' inner workings [»blocJ_2001]

Quote: prefer interfaces over inheritance; unless designed for inheritance, avoid using methods that may be overridden [»blocJ_2001]

Quote: a base class expresses a commonality of representation and calling interface

Quote: Kevo uses family resemblance instead of explicitly sharing object representations [»taivA11_1997]

Quote: Kevo creates objects by copying; it incrementally modifies objects with operations over modules

Quote: classes are a remodeling of records; hierarchical tree structure; members are objects; the prefix of a subclass is the higher level class [»dahlOJ_1967]

Quote: use public derivation (with implicit conversions to a base class) when derivation represents an "isa" relationship of a concept [»stroB_1991]

Quote: the concept-oriented view of inheritance is based on classification in taxonomic systems; models part of the real world [»winkJF8_1992]

Quote: use inheritance ("D is a kind of B") for well-defined relationships and membership ("D has a B") whenever multiple members are possible [»stroB_1991]

Quote: inheritance represents conceptual specialization of a model

Quote: A is a subtype of B if it can be used wherever B is used; A is a subclass of B if it inherits methods and variables [»rodrNR8_1993]

Quote: single inheritance works well if a derived class is more restrictive than the base class; can reuse unrestricted functions [»waldJ2_1992]

Quote: is-a inheritance in object-oriented programming has two very different interpretations [»winkJF8_1992]

Quote: inheritance is important for management of change, especially long-term [»wegnP10_1986]

Quote: use inheritance to isolate users from changes in the implementations of derived classes; e.g., use 'ival_box' to prompt user for an integer value [»koenA12_1995]

Quote: late binding and self-reference allow a programmer to change object behavior without access to its representation

Quote: subsumption is the property that a value of type A is also a value of any supertype B with A<:B [»abadM_1996]

Quote: the product type is a covariant type operator on pairs of types; i.e., A x B <: A' x B' provided that A <: A' and B <: B' [»abadM_1996]

Quote: a function type is a contravariant type operator on pairs of types; i.e., A -> B <: A' -> B' provided that A' <: A and B <: B'; extends to multiple arguments [»abadM_1996]

Quote: methods vary contravariantly from classes to subclasses; despite debate to the contrary

Quote: an update type is an invariant type operator on pairs of types; i.e., if A * B means A and B may be updated, then A * B <: A' * B' provided A=A' and B=B' [»abadM_1996]

Quote: Modula-3 uses a simple, restricted subtype rule, if T <: U, then every value of T is a value of U; arrays and procedures must be basically the same [»cardL_1991]

Quote: allowing the subtype relation to extend to procedures contravariantly interacts badly with subtype rules that require a change of representation [»nelsG_1991]

Quote: Modula-3 does not extend the subtype relation to procedures, arrays, or sets

Quote: the program-oriented view of inheritance is based on extension and substitutability; can replace an object with an object of any subclass [»winkJF8_1992]

Quote: separate inheritance of behavior (behaves-like) from inheritance of representation (subsumes)

Quote: an object is a descendant of a prototype if it satisfies all of the inheritance constraints for fields, methods, and protocols

Quote: a reference value refers to an object belonging to a class or its subclasses; the value 'none' is permissible for any reference [»dahlOJ_1967]

Quote: super-reference allows access to redefined properties without code duplication

Quote: a Smalltalk subclass can override a method in its superclass [»xlrg8_1981]

Quote: use 'super' to access overridden methods of a Smalltalk class [»xlrg8_1981]

Quote: Simula uses ';inner;' to show where subclass actions are embedded [»ichbJD_1972, OK]

Quote: a prefixed procedure embeds its code inside another procedure at 'inner'; like Simula's prefixed classes [»vaucJG10_1975, OK]