R. Ducournau and Michel Habib. On some algorithms for multiple inheritance in objectoriented programming. In J. B ezivin, J-M. Hullot, P. Cointe, and H. Lieberman, editors, Proceedings ECOOP '87, volume 276 of LNCS, pages 243--252, Paris, France, June 15-17 1987. Springer-Verlag.  Home/Search   Document Not in Database   Summary   Related Articles   Check

....with the source code, making the code fragile with respect to changes in the architecture of the class hierarchy. Explicit class references are avoided in languages such as CLOS [40] that impose a linear order on the superclasses. However, such a linearization often leads to unexpected behaviour [15, 16] and violates encapsulation, because it may change the parent child relationships among classes in the inheritance hierarchy [38, 39] Factoring out generic wrappers. Multiple inheritance enables a class to reuse features from multiple base classes, but it does not allow one to write a reusable ....

R. Ducournau and Michel Habib. On some algorithms for multiple inheritance in objectoriented programming. In J. B ezivin, J-M. Hullot, P. Cointe, and H. Lieberman, editors, Proceedings ECOOP '87, volume 276 of LNCS, pages 243--252, Paris, France, June 15-17 1987. Springer-Verlag.

....superclass name was added to Eiffel in 1997 [Mey97] In earlier versions of Eiffel, access to original methods required repeated inheritance of the same class [Mey92] as CLOS [Ste90] that impose a linear order on the superclasses. However, such a linearization often leads to unexpected behaviour [DH87] DHHM92] and violates encapsulation, because it may change the parent child relationships among classes in the inheritance hierarchy [Sny86] Sny87] Limited compositional power. Multiple inheritance allows a class to reuse features from multiple base classes. But unlike mixin inheritance, it ....

R. Ducournau and Michel Habib. On some algorithms for multiple inheritance in object-oriented programming. In J. B ezivin, J-M. Hullot, P. Cointe, and H. Lieberman, editors, Proceedings ECOOP'87, volume 276 of LNCS, pages 243--252, Paris, France, June 15-17 1987. Springer-Verlag.

....queries are on more complicated directed structures. Examples of such combinatorial problems include preprocessing arbitrarily (unrooted) directed trees [NU94] computing the LCA on lattices (used to represent inheritance graphs) AKBLN89] and nding modular coverings in inheritance graphs [DH87, HHS95]. In this paper we introduce a natural extension to all of these LCA problems. We develop algorithms for eciently answering least common ancestor queries on directed acyclic graphs (DAGs) An LCA w of nodes u and v in a DAG is an ancestor of both u and v where w has no descendants that are ....

....the objects are de ned. The idea of formalizing object inheritance in lattice theoretic terms has been proposed by [AKBLN89, Fal90, Fal95, GR80, HN96, McA86, Par87] and others. There has even been considerable interest in further decomposing inheritance graphs into modules that are ecient to query [DH87, HHS95]. The LCA operation is central to such object inheritance formalizations, because it is the natural method to resolve object dependence. Analysis of Genealogical Data Algorithms for nding the LCA are useful for nding ancestral distances in the eld of genealogy. In this eld we are ....

[Article contains additional citation context not shown here]

R. Ducournau and Michel Habib. On some algorithms for multiple inheritance in object-oriented programming. In Jean Bezivin, Jean-Marie Hullot, Pierre Cointe, and Henry Lieberman, editors, ECOOP'87 European Conference on ObjectOriented Programming, volume 276 of Lecture Notes in Computer Science, pages 243-252, Paris, France, 15-17 June 1987. Springer.

....the ancestor queries are on more complicated directed structures. Examples of such combinatorial problems include preprocessing arbitrarily (unrooted) directed trees [31] computing the LCA on lattices (used to represent inheritance graphs) 1] and nding modular coverings in inheritance graphs [17, 24]. In this paper we introduce a natural extension to all of these LCA problems. We develop algorithms for eciently answering least common ancestor queries in DAGs. An LCA w of nodes u and v in a DAG is an ancestor of both u and v where w has no descendants that are ancestors of u and v. We present ....

....order in which the objects are de ned. The idea of formalizing object inheritance in lattice theoretic terms has been proposed by [1, 18, 19, 23, 25, 29, 32] and others. There has even been considerable interest in further decomposing inheritance graphs into modules that are ecient to query [17, 24]. The LCA operation is central to such object inheritance formalizations because it is the natural method to resolve object dependence. Analysis of Genealogical Data Algorithms for nding the LCA are useful for nding ancestral distances in the eld of genealogy. In this eld we are ....

[Article contains additional citation context not shown here]

R. Ducournau and M. Habib. On some algorithms for multiple inheritance in object-oriented programming. In J. Bezivin, J.-M. Hullot, P. Cointe, and H. Lieberman, editors, ECOOP'87 European Conference on Object-Oriented Programming, volume 276 of Lecture Notes in Computer Science, pages 243-252, Paris, France, 15-17 June 1987. Springer.

....of C. Then b would no longer be ambiguous in H since the only reachable definition would be in hH;Fi. 6 Related Work The problem of combining multiple hierarchies has been dealt with in many ways. Snyder[32] divides these into linear and graph oriented approaches. Linear approaches, such as [1, 23, 12, 13, 14], do not model subobject integrity. Graph oriented approaches, all of which are capable of supporting subobject integrity in some way, include extended Smalltalk[2] Trellis Owl[29] CommonObjects[31] ROME[7] and the Krogdahl Stroustrup model discussed here. Some formal models of graph oriented ....

DUCOURNAU, R., AND HABIB, M. On some algorithms for multiple inheritance in object oriented programming. In Proceedings ECOOP '87 (1987), LNCS 276, Springer-Verlag, pp. 243--252.

.... when one considers the corresponding conflicts in the set x multimethod) It is well known that there exist two different solutions to this second problem: the first one consists in resolving conflicts by assigning a priority to classes (this is the solution used by CLOS and formally studied in [DH87] the second one consists in avoiding conflicts by forcing redefinition of ambiguous methods (this is the solution adopted by Eiffel) For the conversion functions we use the second solution since, besides being the one adopted in l , it is, in our opinion, semantically clearer. Thus, we force ....

R. Ducournau and M. Habib. On some algorithms for multiple inheritance in object-oriented programming. In B ezivin, Hullot, Cointe, and Lieberman, editors, Proc. of ECOOP '87 European Conference on ObjectOriented Programming, number 276 in Lecture Notes in Computer Science, pages 243--252. Springer, June 1987.

....of B class. This problem is addressed in section 3.3. Class A template Class B template Class C template Figure 2.2: Data inheritance Several other issues can be raised during the inheriting process, namely handling inherited variables or methods having the same name. As discussed in [Horn 88, Ducournau 87] this is not a trivial job in a multiple inheritance graph. Fortunately, it must be solved semantically, and thus is out of the scope of this work. 2.1.1.2 Changing the class definition In reactive and interactive systems as Smalltalk, it is possible to change the definition of a class ( for ....

R. Ducournau and M. Habib. On Some Algorithms for Multiple Inheritance in Object Oriented Programming. In ECOOP '87, pages 244--252, Paris, France, June 1987.

....mixins are available as a result of two factors: dynamic typing and the notion of linearization. In CLOS, all classes that contribute to an object s behavior are ordered linearly in a class precedence list. The ordering is determined by a linearization algorithm. Various algorithms may be used [22], but they all produce a linear ordering that preserves the partial ordering inherent in the original graph. Each contributing class occurs only once in the resulting precedence list. Linearization serves to disambiguate name clashes in multiple inheritance, but has serious negative consequences. ....

Ducournau, R., and Habib, M. On some algorithms for multiple inheritance in object-oriented programming. In European Conference on ObjectOriented Programming (1987), pp. 243--252.

....to its parent using super just as a Beta prefix refers to its subpatterns using inner. In the Common Lisp Object System (CLOS) and its predecessor, Flavors [13] multiple parent classes may be merged during inheritance. A class s ancestor graph is linearized so that each ancestor occurs only once [7]. With standard method combination for primary methods, the function call next method is used to invoke the next method in the inheritance chain. CLOS supports mixins as a useful technique for building systems out of mixable attributes. A mixin is an abstract subclass; i.e. a subclass definition ....

Ducournau, R., and Habib, M. On some algorithms for multiple inheritance in object-oriented programming. In European Conference on ObjectOriented Programming (1987), pp. 243--252.

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