Oberon-2
programming language

Oberon-2 is an extension of the original Oberon programming language that adds limited reflective programming (reflection) and object-oriented programming facilities, open arrays as pointer base types, read-only field export, and reintroduces the FOR loop from Modula-2.
It was developed in 1991 at ETH Zurich by Niklaus Wirth and Hanspeter Mössenböck, who is now at Institut für Systemsoftware (SSW) of the University of Linz, Austria. Oberon-2 is a superset of Oberon, is fully compatible with it, and was a redesign of Object Oberon.
Oberon-2 inherited limited reflection and single inheritance ("type extension") without the interfaces or mixins from Oberon, but added efficient virtual methods ("type bound procedures"). Method calls were resolved at runtime using C++-style virtual method tables.
Compared to fully object-oriented languages like Smalltalk, in Oberon-2, basic data types and classes are not objects, many operations are not methods, there is no message passing (it can be emulated somewhat by reflection and through message extension, as demonstrated in ETH Oberon), and polymorphism is limited to subclasses of a common class (no duck typing as in Python, and it's not possible to define interfaces as in Java). Oberon-2 does not support encapsulation at object or class level, but modules can be used for this purpose.
Reflection in Oberon-2 does not use metaobjects, but simply reads from type descriptors compiled into the executable binaries, and exposed in the modules that define the types and/or procedures. If the format of these structures are exposed at the language level (as is the case for ETH Oberon, for example), reflection could be implemented at the library level. It could thus be implemented almost entirely at library level, without changing the language code.
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This entry incorporates text from “Oberon-2” on English Wikipedia. Contributors are listed in the page history. Text is available under the Creative Commons Attribution-ShareAlike 4.0 License. Selected authority identifiers and statements are retrieved from Wikidata under CC0; their references and qualifiers remain part of the verification path.