Traversing complex Abstract Syntax Trees (ASTs) typically requires large amounts of tedious boilerplate code. For many operations most of the code simply walks the structure, and only a small portion of the code imple...
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ISBN:
(纸本)9781450336895
Traversing complex Abstract Syntax Trees (ASTs) typically requires large amounts of tedious boilerplate code. For many operations most of the code simply walks the structure, and only a small portion of the code implements the functionality that motivated the traversal in the first place. This paper presents a type-safe Java framework called Shy that removes much of this boilerplate code. In Shy object Algebras are used to describe complex and extensible AST structures. Using Java annotations Shy generates generic boilerplate code for various types of traversals. For a concrete traversal, users of Shy can then inherit from the generated code and override only the interesting cases. Consequently, the amount of code that users need to write is significantly smaller. Moreover, traversals using the Shy framework are also much more structure shy, becoming more adaptive to future changes or extensions to the AST structure. To prove the effectiveness of the approach, we applied Shy in the implementation of a domain-specific questionnaire language. Our results show that for a large number of traversals there was a significant reduction in the amount of user-defined code.
The paper motivates the facilities provided by Description Logics in an object-orientedprogramming scenario. It presents a unification approach of Description Logics and object-orientedprogramming that allows both v...
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ISBN:
(纸本)9780897917889
The paper motivates the facilities provided by Description Logics in an object-orientedprogramming scenario. It presents a unification approach of Description Logics and object-orientedprogramming that allows both views to be conveniently used for different subproblems in a modern software-engineering environment. The main thesis of this paper is that in order to use Description Logics in practical applications, a seamless integration with object-oriented system development methodologies must be realized.
One of the main purposes of object initialisation is to establish invariants such as a field being non-null or an immutable data structure containing specific values. These invariants are then implicitly assumed by th...
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ISBN:
(纸本)9781450309400
One of the main purposes of object initialisation is to establish invariants such as a field being non-null or an immutable data structure containing specific values. These invariants are then implicitly assumed by the rest of the implementation, for instance, to ensure that a field may be safely dereferenced or that immutable data may be accessed concurrently. Consequently, letting an object escape from its constructor is dangerous;the escaping object might not yet satisfy its invariants, leading to errors in code that relies on them. Nevertheless, preventing objects entirely from escaping from their constructors is too restrictive;it is often useful to call auxiliary methods on the object under initialisation or to pass it to another constructor to set up mutually-recursive structures. We present a type system that tracks which objects are fully initialised and which are still under initialisation. The system can be used to prevent objects from escaping, but also to allow safe escaping by making explicit which objects might not yet satisfy their invariants. We designed, formalised and implemented our system as an extension to a non-null type system, but it is not limited to this application. Our system is conceptually simple and requires little annotation overhead;it is sound and sufficiently expressive for many common programming idioms. Therefore, we believe it to be the first such system suitable for mainstream use.
This paper is about reusable, efficient implementations of complex algorithms and their integration into software packages. It seems that this problem is not yet well understood, and that it is not at all clear how ob...
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This paper is about reusable, efficient implementations of complex algorithms and their integration into software packages. It seems that this problem is not yet well understood, and that it is not at all clear how object-oriented and other approaches may contribute to a solution. We analyze the problem and try to reduce it to a few key design goals. Moreover, we discuss various existing approaches in light of these goals, and we briefly report experiences with experimental case studies, in which these goals were rigorously addressed.
Standard object-oriented languages do not provide language support for modeling changing collections of interdependent objects. We propose that R++, an integration of the rule and object-oriented paradigms, provides a...
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Standard object-oriented languages do not provide language support for modeling changing collections of interdependent objects. We propose that R++, an integration of the rule and object-oriented paradigms, provides a mechanism for easily implementing such models. R++ extends C++ by adding a new programming construct called the path-based rule. Such data-driven rules are restricted to follow pointers between objects, and are like ''automatic methods'' that are triggered by changes to monitored objects. Path-based rules encourage a more abstract level of programming, and unlike previous rule integrations, are not at odds with the object-oriented paradigm and offer performance advantages for natural applications.
A new visual notation is proposed for precisely expressing constraints on object-oriented models, as an alternative to mathematical logic notation used in methods such as Syntropy and Catalysis. The notation is potent...
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A new visual notation is proposed for precisely expressing constraints on object-oriented models, as an alternative to mathematical logic notation used in methods such as Syntropy and Catalysis. The notation is potentially intuitive, expressive, integrates well with existing visual notations, and has a clear and unambiguous semantics. It is reminiscent of informal diagrams used by mathematicians for illustrating relations, and borrows much from Venn diagrams. It may be viewed as a generalization of instance diagrams.
This paper explains how patterns can be used to describe the implementation of other patterns. It is demonstrated how certain design patterns can describe their own design. This is a fundamental reflexive relationship...
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This paper explains how patterns can be used to describe the implementation of other patterns. It is demonstrated how certain design patterns can describe their own design. This is a fundamental reflexive relationship in pattern relationships. The process of assembling patterns by other patterns is named pattern tiling. Tiling enables us to interweave simple understood concepts of patterns into their complex real-life implementation. Several pattern tilings for the Interpreter design pattern are illustrated.
作者：
Riehle, DUbilab
Union Bank of Switzerland Zurich Switzerland
Software design patterns are the core abstractions from successful recurring problem solutions in software design. Composite design patterns are the core abstractions from successful recurring frameworks. A composite ...
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Software design patterns are the core abstractions from successful recurring problem solutions in software design. Composite design patterns are the core abstractions from successful recurring frameworks. A composite design pattern is a pattern that is best described as the composition of further patterns the integration of which shows a synergy that makes the composition more than just the sum of its parts. This paper presents examples of composite patterns, discusses a role-based analysis and composition technique, and demonstrates that composite patterns extend the pattern idea from single problem solutions to object-oriented frameworks.
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