Record manipulation in prolog

Prolog is a relatively new programming language that has proved excellent for symbolic computation. However, Prolog was not specifically designed for industrial scale work and it lacks some standard features that are useful for reading, maintaining and debugging large programs. In particular, Prolog has no record mechanism, and programs often require major changes when data structures are modified. The record is a standard data abstraction concept that improves the robustness of programs. The main advantage in using records is that data structures can be modified and extended with minimal repercussion to program code. Furthermore, the use of significant names to access data fields means that the intent of code is generally clearer. We present a set of primitive operators that support a readable and robust programming style for the manipulation of record data structures in standard Prolog. The proposal covers both simple and imbricated record types and handles selective modification of records cleanly. We also treat property lists and records in a uniform way. These benefits are achieved with minimal overhead while retaining the traditional Prolog non-deterministic style.     

The Implementation Technology of the Mercury Debugger

Every programming language needs a debugger. Mercury now has three debuggers: a simple procedural debugger similar to the tracing systems of Prolog implementations, a prototype declarative debugger, and a debugger based on the idea of automatic trace analysis. In this paper, we present the shared infrastructure that underlies the three debuggers, and describe the implementation of the procedural debugger. We give our reasons for each of our main design decisions, and show how several of these decisions are rooted in our experience with the debugging of large programs working with large data structures.     

How should Prolog computation Be represented for practical use?

We propose a visual computation model called theBox and Plane Model (BPM), which visually clarifies the semantics of backtracking, the cut operator, and side-effects, thus allowing the procedural features of Prolog to be grasped. On the bases of the BPM, we developed a visual debugger for Prolog, PROEDIT2, which has proved that this kind of pragmatic computation model for Prolog increases the efficiency of the debugging work.     

P#: a concurrent Prolog for the .NET framework

We discuss P#, our implementation of a tool that allows interoperation between a concurrent superset of the Prolog programming language and C#. This enables Prolog to be used as a native implementation language for Microsoft's .NET platform. P# compiles a linear logic extension of Prolog to C# source code. We can thus create C# objects from Prolog and use C#'s graphical, networking and other libraries. We add language constructs on the Prolog side that allow concurrent Prolog code to be written. A primitive predicate is provided that evaluates a Prolog structure on a newly forked thread. Communication between threads is based on the unification of variables contained in such a structure. It is also possible for threads to communicate through a globally accessible table. All of the new features are available to the programmer through new built-in Prolog predicates. We discuss two software engineering tools implemented using P#. Copyright © 2004 John Wiley & Sons, Ltd.     

Prolog/Rex-a way to extend Prolog for better knowledgerepresentation

Prolog/Rex represents a powerful amalgamation of the latest techniques for knowledge representation and processing, rich in semantic features that ease the difficult task of encoding heterogeneous knowledge of real-world applications. The Prolog/Rex concept mechanism lets a user represent domain entities in terms of their structural and behavioral properties, including multiple inheritance, arbitrary user-defined relations among entities, annotated values (demons), incomplete knowledge, etc. A flexible rule language helps the knowledge engineer capture human expertise and provide flexible control of the reasoning process. Additional Prolog/Rex strength that cannot be found in any other hybrid language made on top of Prolog is language level support for keeping many potentially contradictory solutions to a problem, allowing possible solutions and their implications to be automatically generated and completely explored before they are committed. The same mechanism is used to model time-states, which are useful in planning and scheduling applications of Prolog/Rex     

Full prolog and scheduling or-parallelism in muse

Muse is a simple and efficient approach to Or-parallel implementation of the full Prolog language. It is based on havingmultiplesequential Prolog engines, each with its local address space, and some shared memory space. It is currently implemented on a number of bus-based and switch-based multiprocessors. The sequential SICStus Prolog system has been adapted to Or-parallel implementation with very low extra overhead in comparison with other approaches. The Muse performanhce results are very encouraging in absolute and relative terms.The Muse execution model and its performance results on two different multiprocessor machines for a parallel version of Prolog, named Commit Prolog, have been presented in previous papers. This paper discusses supporting the full Prolog language and describes mechanisms being developed for scheduling Or-parallelism in Muse. It also presents performance results of the Muse implementation on Sequent Symmetry after supporting full Prolog. The results show that the extra overhead associated with supporting the full Prolog language is negligible.     

UCB策略在Prolog中的应用

Prolog(Programming in Logic)程序语言是一种逻辑程序设计语言.它是在逻辑学理论基础上建立起来的并广泛应用在人工智能研究中.这几十年已经出现了各具特色的Prolog编译器,而且各种编译器也都很成功.虽然在现阶段已经出现了各种版本Prolog编译器,但是Prolog编译器的发展空间还是很大.本文先通过现代Prolog编译器的不足,介绍了新Prolog编译器的特点,然后简单叙述了Prolog编译器词法分析和语法分析的过程,最后介绍了UCB策略.     

QD-Janus: A sequential implementation of Janus in Prolog

Janus is a language designed for distributed constraint programming. This paper describes QD-Janus, a sequential implementation of Janus in Prolog. The compiler uses a number of novel analyses and optimizations to improve the performance of the system. The choice of Prolog as the target language for a compiler, although unusual, is motivated by the following: (i) the semantic gap between Janus and Prolog is much smaller than that between Janus and, say, C or machine language—this simplifies the compilation process significantly, and makes it possible to develop a system with reasonable performance fairly quickly; (ii) recent progress in Prolog implementation techniques, and the development of Prolog systems whose speeds are comparable to those of imperative languages, indicates that the translation to Prolog need not entail a significant performance loss compared to native code compilers; and (iii) compilation to Prolog can benefit immediately from a significant body of work on, and implementations of, parallel Prolog systems. Our experience indicates that translation of logic programming languages to Prolog, accompanied by the development of good program analysis and optimization tools, is an effective way to quickly develop flexible and portable implementations with good performance and low cost.     

Translational Semantics for a Conceptual Level Query Language

A conceptual level database language for the entity relationship (ER) model implicitly contains integrities basic to ER concepts and special retrieval semantics for inheritances of attributes and relationships.Prolog,which belongs to the logical and physical level,cannot be used as a foundation to directly define the database language.It is shown how Prolog can be enhanced to understand the concepts of entities,relationships,attributes and is-a relationships.The enhanced Prolog is then used as a foundation to define the semantics of a database query language for the ER model.The three basic functions of model specification,updates and retrievals are defined.     

高阶函数式语言到逻辑式语言的转换

本文给出高阶函数式语言到Ｐｒｏｌｏｇ语言的一种转换技术．其中主要用到抽象闭包分析、Ｌａｍｂｄａ提升、顺序化以及Ｐｒｏｌｏｇ中的Ｃａｌ技术．本文的研究重点在于高阶性的处理上.     

Logic programming and compiler writing

The concept of ‘logic programming’, and its practical application in the programming language Prolog, are explained from first principles. The ideas are illustrated by describing in detail one sizable Prolog program which implements a simple compiler. The advantages and practicability of using Prolog for ‘real’ compiler implementation are discussed.     

A logical approach to program analysis

This paper describesMicroScope, a framework for developing analysis tools for Lisp programs. MicroScope uses a knowledge-intensive approach for program representation and analysis. The analysis tools share a common object oriented program database, and a common Prolog inference engine. The use of Prolog and a declarative representation for programs permits sharing of information, and provides high bandwidth communication between diverse analysis tools. It also supports program specification and debugging activities in the same framework. Extensions to Prolog to support analysis are described, and two tools, theCritic and theExpector, are presented.This work supported in part by Hewlett-Packard Company, the National Science foundation Under Grant Number MCS81-21750 and the Defense Advanced Research Projects Agency under contract number DAAK11-84-K-0017.     

Critical factors in the evolution of logic programming and Prolog

Logic programming has received much critical attention over the past two decades from both a language perspective and as a methodology for practical problem solving. This paper presents a historical foundation of the approach and examines the development of Prolog since its first implementation. An analysis of the use of Prolog in commercial, research and teaching environments shows that there is an established base of users and that, after a period of rapid growth, the language currently enjoys continuing activity. The key to its success so far is due to its continuing evolution by including features that were not seen as being within the original concept as a pure logic language. Significant features which have contributed to the success of Prolog include integration with other languages, object oriented extensions, constraint representation, parallel execution as well as improved speed and robustness. Applications databases are analysed with respect to type of application, system status, type of developer, hardware platform, country of origin and the Prolog implementation used. Factors contributing to the success of Prolog are identified and likely future developments are explored.     

Natural language processing: a prolog perspective

Natural language processing (NLP) is a vibrant field of interdisciplinary Computer Science research. Ultimately, NLP seeks to build intelligence into software so that software will be able to process a natural language as skillfully and artfully as humans. Prolog, a general purpose logic programming language, has been used extensively to develop NLP applications or components thereof. This report is concerned with introducing the interested reader to the broad field of NLP with respect to NLP applications that are built in Prolog or from Prolog components.     

An Operator Precedence Parser for Standard Prolog Text

Prolog is a language with a dynamic grammar which is the result of embedded operator declarations. The parsing of such a language cannot be done easily by means of standard tools. Most often, an existing parsing technique for a static grammar is adapted to deal with the dynamic constructs. This paper uses the syntax definition as defined by the ISO standard for the Prolog language. It starts with a brief discussion of the standard, highlighting some aspects that are important for the parser, such as the restrictions on the use of operators as imposed by the standard in order to make the parsing deterministic. Some possible problem areas are also indicated. As output is closely related to input in Prolog, both are treated in this paper. Some parsing techniques are compared and an operator precedence parser is chosen to be modified to deal with the dynamic operator declarations. The necessary modifications are discussed and an implementation in C is presented. Performance data are collected and compared with a public domain Prolog parser written in Prolog. It is the first efficient public domain parser for Standard Prolog that actually works and deals with all the details of the syntax.     

PARLOG and its applications

The key concepts of the parallel logic programming language PARLOG are introduced by comparing the language with Prolog. Some familiarity with Prolog and with the concepts of logic programming is assumed. Two major application areas of PARLOG, systems programming and object-oriented programming, are illustrated. Other applications are briefly surveyed     

An overview of JML tools and applications

The Java Modeling Language (JML) can be used to specify the detailed design of Java classes and interfaces by adding annotations to Java source files. The aim of JML is to provide a specification language that is easy to use for Java programmers and that is supported by a wide range of tools for specification typechecking, runtime debugging, static analysis, and verification.This paper gives an overview of the main ideas behind JML, details about JML’s wide range of tools, and a glimpse into existing applications of JML.     

对语义网查询语言的逻辑推理优化

为了在SeRQL RDF查询语言的语境中对查询进行的转换和优化,提出了使用Prolog语言来处理推理策略原型的RDF图的方法,以及将SeRQL查询转化为优化Prolog目标的算法,实现了对语义网语言的结构化变换,并验证了Prolog模块的性能。     

String pattern-matching in Prolog

A pattern-matching feature for the Prolog language is described. Through the use of patterns, introduced as Prolog predicates, the feature favors the specification of string handling algorithms in a declarative style. A number of convenient pre-defined patterns, adapted from SNOBOL 4, are included. The use of two-level grammars as a paradigm for developing Prolog programs incorporating the pattern-matching feature is also discussed.