Type extension and efficient AST manipulation

Oberon-2 is an object-oriented language with a class structure based on type extension. The runtime structure of Oberon-2 is described and the low-level mechanism for dynamic type checking explained. It is shown that the superior type-safety of the language, when used for programming styles based on heterogeneous, pointer-linked data structures, has an entirely negligible cost in runtime performance.

Type Test Elimination using Typeflow Analysis

Programs written in languages of the Oberon family usually contain runtime tests on the dynamic type of variables. In some cases it may be desirable to reduce the number of such tests. Typeflow analysis is a static method of determining bounds on the types that objects may possess at runtime. We show that this analysis is able to reduce the number of tests in certain plausible circumstances. Furthermore, the same analysis is able to detect certain program errors at compile time, which would normally only be detected at program execution. This paper introduces the concepts of typeflow analysis and details its use in the reduction of runtime overhead in Oberon-2.

Evaluating the Java Virtual Machine as a Target for Languages Other Than Java

The portability and runtime safety of programs which are executed on the Java Virtual Machine (JVM) makes the JVM an attractive target for compilers of languages other than Java. Unfortunately, the JVM was designed with language Java in mind, and lacks many of the primitives required for a straighforward implementation of other languages. Here, we discuss how the JVM may be used to implement other object-oriented languages. As a practical example of the possibilities, we report on a comprehensive case study. The open source Gardens Point Component Pascal compiler compiles the entire Component Pascal language, a dialect of Oberon-2, to JVM bytecodes. This compiler achieves runtime efficiencies which are comparable to native-code implementations of procedural languages.

Implementing languages other than Java on the Java Virtual Machine

The portability and runtime safety of programs which are executed on the Java Virtual Machine (JVM) makes the JVM an attractive target for compilers of languages other than Java. Unfortunately, the JVM was designed with language Java in mind, and lacks many of the primitives required for a straight forward implementation of other languages. Here, we discuss how the JVM may be used to implement other object oriented languages. As a practical example of the possibilities, we report on a comprehensive case study. The open source Gardens Point Component Pascal compiler compiles the entire Component Pascal language, a dialect of Oberon 2, to JVM bytecodes. This compiler achieves runtime efficiencies which are comparable to native code implementations of procedural languages.

Karl Gentner als Oberon, Rollenbild, Brustbild, in: Carl Maria von Weber: Oberon

Signatur des Originals: S 36/F03865

Karl Gentner als Oberon, Rollenbild, Brustbild, in: Carl Maria von Weber: Oberon

Signatur des Originals: S 36/F03895

Paul Kalisch als Hüon von Bordeaux, Rollenbild, in: Carl Maria von Weber: Oberon

Signatur des Originals: S 36/F04854

Heinrich Sauer als Oberon, Annemarie Rothe als Titania, Szenenfoto, in: William Shakespeare: Ein Sommernachtstraum

Signatur des Originals: S 36/F06162

Ada Westhofen-Robinson, Rollenbild, in: Carl Maria von Weber: Oberon

Signatur des Originals: S 36/F06033

Alma Wendorf-Weintraub, Rollenbild, in: Carl Maria von Weber: Oberon, Frankfurt a. M., 1882

Signatur des Originals: S 36/F10246

Inez Fabbri-Mulder als Rezia, Rollenbild, in: Carl Maria von Weber: Oberon or The Elf Kings̀ Oath

Signatur des Originals: S 36/F11515

Inez Fabbri-Mulder als Rezia, Rollenbild, Profil, in: Carl Maria von Weber: Oberon or The Elf Kings̀ Oath

Signatur des Originals: S 36/F11525

Maria Müller als Rezia, Rollenbild, in: Carl Maria von Weber: Oberon or The Elf King's Oath

Signatur des Originals: S 36/F11675

Maria Müller als Rezia, Rollenbild, Brustbild, in: Carl Maria von Weber: Oberon or The Elf King's Oath

Signatur des Originals: S 36/F11678

Oberon : Huon: Allmächtiger Himmel! Ich bin betrogen!

Signatur des Originals: S 36/G00176