Difference between revisions of "Replication"
(→Three cases of non-conforming repeated inheritance) |
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====Three cases of conforming repeated inheritance==== | ====Three cases of conforming repeated inheritance==== | ||
− | Lets look now at different variants of class | + | Lets look now at different variants of class D1. They looks exactly as class D1 except that they inherit conforming from B (twice) and therefore need to solve the conflicts between f1-f2 and g1-g2 by selecting. Let DC1_fx_gx be the variant of D1 that selects fx and gx. |
+ | There are four such variants: DC1_f1_g1, DC1_f1_g2, DC1_f2_g1, DC1_f2_g2. | ||
− | Even though the following examples contain conforming inheritance, we will start by investigating their semantics in the case where static and dynamic type are equal. | + | Even though the following examples contain conforming inheritance, we will start by investigating their semantics in the case where static and dynamic type are equal. When the variants DC1 |
Revision as of 10:45, 25 August 2006
Work in progress!
We start with some very basic examples, for this we consider all the classes not to be inherited by ANY.
Contents
Example set
Basic cases of direct repeated inheritance
The following set of example will base on class B:
class B feature f: INTEGER g do f := f + 1 end end
Three cases of non-conforming repeated inheritance
Lets have look at D1 that repeatedly inherits from B:
class D1 inherit {NONE} B rename f as f1, g as g1 end B rename f as f2, g as g2 end feature end
And an informal description of the semantics: An object of class D1 contains two physical attributes (f1 and f2). A call to feature g1 results in f1 being incremented and a call to g2 increments f2.
Lets do the same for D2:
class D2 inherit {NONE} B rename g as g1 end B rename g as g2 end feature end
An object of class D2 contains one physical attribute (f). A call to either g1 or g2 results in f being incremented.
Class D3 should be rejected by the compiler:
class D3 inherit {NONE} B rename f as f1 end B rename f as f2 end feature end
Since an object of class D3 would have two physical attributes f1 and f2, it is not clear which one g should increment.
Three cases of conforming repeated inheritance
Lets look now at different variants of class D1. They looks exactly as class D1 except that they inherit conforming from B (twice) and therefore need to solve the conflicts between f1-f2 and g1-g2 by selecting. Let DC1_fx_gx be the variant of D1 that selects fx and gx. There are four such variants: DC1_f1_g1, DC1_f1_g2, DC1_f2_g1, DC1_f2_g2.
Even though the following examples contain conforming inheritance, we will start by investigating their semantics in the case where static and dynamic type are equal. When the variants DC1