View source for ObjVlisp

'''ObjVlisp''' is a 1984 object-oriented extension of [[Vlisp]]<ref name="Cointe1987">{{cite journal|last1=Cointe|first1=Pierre|title=Metaclasses are first class: The ObjVlisp Model|journal=ACM SIGPLAN Notices|volume=22|issue=12|year=1987|pages=156–162|issn=0362-1340|doi=10.1145/38807.38822}}</ref>–Vincennes LISP, a LISP dialect developed since 1971 at the [[Paris 8 University|University of Paris VIII – Vincennes]]. It is noteworthy as one of the earliest implementations of the concept of [[metaclass]]es, and in particular explicit (as opposed to implicit) metaclasses. In the ObjVlisp model, "each entity is an instance of a single class. Classes are instances of other classes, called metaclasses. This model allows for extension of the static part of OOL, i.e. the structural aspects of objects considered as implementation of abstract data types"<ref>{{cite book|last1=Ferber|first1=J.|title=Conference proceedings on Object-oriented programming systems, languages and applications - OOPSLA '89|chapter=Computational reflection in class based object-oriented languages|year=1989|pages=317–326|doi=10.1145/74877.74910|isbn=978-0897913331|s2cid=305719}}</ref>

ObjVlisp provided a far more flexible metaclass model than that provided by earlier object-oriented languages, especially [[Smalltalk]]. In Smalltalk-80, whenever a new class is created, a corresponding metaclass is created automatically; it does not have a name independent of that of the metaclass for which it was created–metaclasses are implicit rather than explicit. By contrast, in ObjVlisp, it is possible to define named metaclasses, and when defining a class one must specify which named metaclass it will instantiate.<ref name="BriotCointe1989">{{cite book|last1=Briot|first1=J.-P.|title=Conference proceedings on Object-oriented programming systems, languages and applications - OOPSLA '89|last2=Cointe|first2=P.|chapter=Programming with explicit metaclasses in Smalltalk-80|year=1989|pages=419–431|doi=10.1145/74877.74921|isbn=978-0897913331|s2cid=15529194}}</ref>

The explicit metaclass support in ObjVlisp influenced the provision of the same capability in the [[Common Lisp Object System]].<ref>{{cite book|last1=Graube|first1=Nicolas|title=ECOOP '88 European Conference on Object-Oriented Programming|chapter=Reflexive Architecture: From ObjVLisp to CLOS|volume=322|year=1988|pages=110–127|issn=0302-9743|doi=10.1007/3-540-45910-3_7|series=Lecture Notes in Computer Science|isbn=978-3-540-50053-7}}</ref>

The ObjVlisp object model was later implemented in [[Prolog]] to produce [[ObjVProlog]].<ref name="MalenfantLapalme1991">{{cite journal|last1=Malenfant|first1=J.|last2=Lapalme|first2=G.|last3=Vaucher|first3=J.|title=ObjVProlog-D: a reflexive object-oriented logic language for distributed computing|journal=ACM SIGPLAN OOPS Messenger|volume=2|issue=2|year=1991|pages=78–81|issn=1055-6400|doi=10.1145/127070.127089|doi-access=free}}</ref><ref>"ObjVProlog: Metaclasses in Logic", J. Malenfant, ECOOP '89, Cambridge U Press 1989, pp.&nbsp;257–269</ref> Both [[Python (programming language)|Python]] and Converge implement a meta-class system that is equivalent of that of ObjVLisp.<ref>{{Cite web|url=http://tratt.net/laurie/blog/entries/metacircularity.html|title=Metacircularity|last=Tratt|first=Laurence|date=September 12, 2005|website=tratt.net|access-date=2017-07-21}}</ref><ref>{{Cite book|title=500 Lines or less|last1=DiBernardo|first1=Michael|last2=Brown|first2=Amy|date=2016|publisher=Lulu.com|isbn=9781329871274|location=[S.l.]|chapter=Chapter 14, A Simple Object Model|oclc=986953971|chapter-url=https://www.aosabook.org/en/500L/a-simple-object-model.html}}</ref>

==References==
{{Reflist}}

[[Category:Object-oriented programming languages]]
[[Category:Lisp programming language family]]


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