11 – Logic Paradigm and Prolog
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From Plain Prolog to Logtalk Objects: Effective Code Encapsulation and Reuse
From Plain Prolog to Logtalk Objects: Effective Code Encapsulation and Reuse Paulo Moura Dep. of Computer Science, Univ. of Beira Interior, Portugal Center for Research in Advanced Computing Systems INESC Porto, Portugal http://logtalk.org/ [email protected] ICLP 2009 Inivited Talk Someone said I need one... 2 Spoilers • Objects in a Prolog world • Logtalk design goals • Logtalk architecture • Logtalk versus Prolog and Prolog modules • Logtalk overview and quick tour • Some demos (if time allows) • Logtalk as a portable Prolog application • Logtalk programming support 3 A warning... • I have a laser and I’m not afraid to use it ... Beware of asking embarrassing questions! • But please feel free to interrupt and ask nice ones that make the speaker shine! 4 A bit of history... • Project started in January 1998 • First version for registered users in July 1998 • First public beta in October 1998 • First stable version in February 1999 5 Logtalk in numbers • Compiler + runtime: ~11000 lines of Prolog code • 37 major releases, 122 including minor ones • Current version: Logtalk 2.37.2 minor release number major release number second generation of Logtalk • ~1500 downloads/month (so many earthlings, so little time) 6 Logtalk distribution • Full sources (compiler/runtime, Prolog config files, libraries) • MacOS X (pkg), Linux (rpm), Debian (deb), and Windows (exe) installers XHTML and PDF User and Reference Manuals • (121 + 144 pages) • +90 programming examples • Support for several text editors and syntax highlighters (text services and code publishing) 7 Objects in Prolog?!? We’re being invaded! 8 Objects have identifiers and dynamic state! • It seems Prolog modules are there first: Identifier! :- module(broadcast, [...]). -
Chapter 5 Names, Bindings, and Scopes
Chapter 5 Names, Bindings, and Scopes 5.1 Introduction 198 5.2 Names 199 5.3 Variables 200 5.4 The Concept of Binding 203 5.5 Scope 211 5.6 Scope and Lifetime 222 5.7 Referencing Environments 223 5.8 Named Constants 224 Summary • Review Questions • Problem Set • Programming Exercises 227 CMPS401 Class Notes (Chap05) Page 1 / 20 Dr. Kuo-pao Yang Chapter 5 Names, Bindings, and Scopes 5.1 Introduction 198 Imperative languages are abstractions of von Neumann architecture – Memory: stores both instructions and data – Processor: provides operations for modifying the contents of memory Variables are characterized by a collection of properties or attributes – The most important of which is type, a fundamental concept in programming languages – To design a type, must consider scope, lifetime, type checking, initialization, and type compatibility 5.2 Names 199 5.2.1 Design issues The following are the primary design issues for names: – Maximum length? – Are names case sensitive? – Are special words reserved words or keywords? 5.2.2 Name Forms A name is a string of characters used to identify some entity in a program. Length – If too short, they cannot be connotative – Language examples: . FORTRAN I: maximum 6 . COBOL: maximum 30 . C99: no limit but only the first 63 are significant; also, external names are limited to a maximum of 31 . C# and Java: no limit, and all characters are significant . C++: no limit, but implementers often impose a length limitation because they do not want the symbol table in which identifiers are stored during compilation to be too large and also to simplify the maintenance of that table. -
A Concurrent PASCAL Compiler for Minicomputers
512 Appendix A DIFFERENCES BETWEEN UCSD'S PASCAL AND STANDARD PASCAL The PASCAL language used in this book contains most of the features described by K. Jensen and N. Wirth in PASCAL User Manual and Report, Springer Verlag, 1975. We refer to the PASCAL defined by Jensen and Wirth as "Standard" PASCAL, because of its widespread acceptance even though no international standard for the language has yet been established. The PASCAL used in this book has been implemented at University of California San Diego (UCSD) in a complete software system for use on a variety of small stand-alone microcomputers. This will be referred to as "UCSD PASCAL", which differs from the standard by a small number of omissions, a very small number of alterations, and several extensions. This appendix provides a very brief summary Of these differences. Only the PASCAL constructs used within this book will be mentioned herein. Documents are available from the author's group at UCSD describing UCSD PASCAL in detail. 1. CASE Statements Jensen & Wirth state that if there is no label equal to the value of the case statement selector, then the result of the case statement is undefined. UCSD PASCAL treats this situation by leaving the case statement normally with no action being taken. 2. Comments In UCSD PASCAL, a comment appears between the delimiting symbols "(*" and "*)". If the opening delimiter is followed immediately by a dollar sign, as in "(*$", then the remainder of the comment is treated as a directive to the compiler. The only compiler directive mentioned in this book is (*$G+*), which tells the compiler to allow the use of GOTO statements. -
ALGORITHMS for ARTIFICIAL INTELLIGENCE in Apl2 By
MAY 1986 REVISED Nov 1986 TR 03·281 ALGORITHMS FOR ARTIFICIAL INTELLIGENCE IN APl2 By DR JAMES A· BROWN ED EUSEBI JANICE COOK lEO H GRONER INTERNATIONAL BUSINESS MACHINES CORPORATION GENERAL PRODUCTS DIVISION SANTA TERESA LABORATORY SAN JOSE~ CALIFORNIA ABSTRACT Many great advances in science and mathematics were preceded by notational improvements. While a g1yen algorithm can be implemented in any general purpose programming language, discovery of algorithms is heavily influenced by the notation used to Lnve s t Lq a t.e them. APL2 c o nce p t.ua Lly applies f unc t Lons in parallel to arrays of data and so is a natural notation in which to investigate' parallel algorithins. No c LaLm is made that APL2 1s an advance in notation that will precede a breakthrough in Artificial Intelligence but it 1s a new notation that allows a new view of the pr-obl.ems in AI and their solutions. APL2 can be used ill problems tractitionally programmed in LISP, and is a possible implementation language for PROLOG-like languages. This paper introduces a subset of the APL2 notation and explores how it can be applied to Artificial Intelligence. 111 CONTENTS Introduction. • • • • • • • • • • 1 Part 1: Artificial Intelligence. • • • 2 Part 2: Logic... · • 8 Part 3: APL2 ..... · 22 Part 4: The Implementations . · .40 Part 5: Going Beyond the Fundamentals .. • 61 Summary. .74 Conclus i ons , . · .75 Acknowledgements. • • 76 References. · 77 Appendix 1 : Implementations of the Algorithms.. 79 Appendix 2 : Glossary. • • • • • • • • • • • • • • • • 89 Appendix 3 : A Summary of Predicate Calculus. · 95 Appendix 4 : Tautologies. · 97 Appendix 5 : The DPY Function. -
Event Management for the Development of Multi-Agent Systems Using Logic Programming
Event Management for the Development of Multi-agent Systems using Logic Programming Natalia L. Weinbachy Alejandro J. Garc´ıa [email protected] [email protected] Laboratorio de Investigacio´n y Desarrollo en Inteligencia Artificial (LIDIA) Departamento de Ciencias e Ingenier´ıa de la Computacio´n Universidad Nacional del Sur Av. Alem 1253, (8000) Bah´ıa Blanca, Argentina Tel: (0291) 459-5135 / Fax: (0291) 459-5136 Abstract In this paper we present an extension of logic programming including events. We will first describe our proposal for specifying events in a logic program, and then we will present an implementation that uses an interesting communication mechanism called \signals & slots". The idea is to provide the application programmer with a mechanism for handling events. In our design we consider how to define an event, how to indicate the occurrence of an event, and how to associate an event with a service predicate or handler. Keywords: Event Management. Event-Driven Programming. Multi-agent Systems. Logic Programming. 1 Introduction An event represents the occurrence of something interesting for a process. Events are useful in those applications where pieces of code can be executed automatically when some condition is true. Therefore, event management is helpful to develop agents that react to certain occurrences produced by changes in the environment or caused by another agents. Our aim is to support event management in logic programming. An event can be emitted as a result of the execution of certain predicates, and will result in the execution of the service predicate or handler. For example, when programming a robot behaviour, an event could be associated with the discovery of an obstacle in its trajectory; when this event occurs (generated by some robot sensor), the robot might be able to react to it executing some kind of evasive algorithm. -
A View of the Fifth Generation and Its Impact
AI Magazine Volume 3 Number 4 (1982) (© AAAI) Techniques and Methodology A View of the Fifth Generation And Its Impact David H. D. Warren SRI International Art$icial Intellagence Center Computer Scaence and Technology Davzsaon Menlo Park, Calafornia 94025 Abstract is partly secondhand. I apologise for any mistakes or misin- terpretations I may therefore have made. In October 1981, .Japan announced a national project to develop highly innovative computer systems for the 199Os, with the title “Fifth Genera- tion Computer Systems ” This paper is a personal view of that project, The fifth generation plan its significance, and reactions to it. In late 1978 the Japanese Ministry of International Trade THIS PAPER PRESENTS a personal view of the <Japanese and Industry (MITI) gave ETL the task of defining a project Fifth Generation Computer Systems project. My main to develop computer syst,ems for the 199Os, wit,h t,he title sources of information were the following: “Filth Generation.” The prqject should avoid competing with IBM head-on. In addition to the commercial aspects, The final proceedings of the Int,ernational Conference it should also enhance Japan’s international prestige. After on Fifth Generat,ion Computer Systems, held in Tokyo in October 1981, and the associated Fifth Generation various committees had deliberated, it was finally decided research reports distributed by the Japan Information to actually go ahead with a “Fifth Generation Computer Processing Development Center (JIPDEC); Systems” project in 1981. The project formally started in April, 1982. Presentations by Koichi Furukawa of Electrotechnical The general technical content of the plan seems to be Laboratory (ETL) at the Prolog Programming Environ- largely due to people at ETL and, in particular, to Kazuhiro ments Workshop, held in Linkoping, Sweden, in March 1982; Fuchi. -
Concise Introduction to C++
i i final3 2012/4/19 page 47 i i Chapter 2 Concise Introduction to C++ C++ seems to be most suitable for many practical applications. Indeed, C++ is sufficiently high-level to allow transparent object-oriented programming and efficient use of human resources, yet is also sufficiently low-level to have types, variables, pointers, arrays, and loops to allow efficient use of computer resources. In this chapter, we give a concise description of C++ and illustrate its power as an object-oriented programming language. In particular, we show how to construct and use abstract mathematical objects such as vectors and matrices. We also explain the notion of a template class, which can be filled with a concrete type later on in compilation time. We also discuss inheritance and illustrate its potential. 2.1 Objects As we have seen above, C is a language based on functions. Every command is also a function that returns a value that can be further used or abandoned, according to the wish of the programmer. Furthermore, programmers can write their own functions, which may also return variables of the type specified just before the function name. When the function is called, a temporary, unnamed variable is created to store the returned value until it has been used. C++, on the other hand, is an object-oriented programming language. In this kind of language, the major concern is not the functions that can be executed but rather the objects upon which they operate. Although C++ supports all the operations and features available in C, its point of view is different. -
CSC384: Intro to Artificial Intelligence Brief Introduction to Prolog
CSC384: Intro to Artificial Intelligence Brief Introduction to Prolog Part 1/2: Basic material Part 2/2 : More advanced material 1 Hojjat Ghaderi and Fahiem Bacchus, University of Toronto CSC384: Intro to Artificial Intelligence Resources Check the course website for several online tutorials and examples. There is also a comprehensive textbook: Prolog Programming for Artificial Intelligence by Ivan Bratko. 2 Hojjat Ghaderi and Fahiem Bacchus, University of Toronto What‟s Prolog? Prolog is a language that is useful for doing symbolic and logic-based computation. It‟s declarative: very different from imperative style programming like Java, C++, Python,… A program is partly like a database but much more powerful since we can also have general rules to infer new facts! A Prolog interpreter can follow these facts/rules and answer queries by sophisticated search. Ready for a quick ride? Buckle up! 3 Hojjat Ghaderi and Fahiem Bacchus, University of Toronto What‟s Prolog? Let‟s do a test drive! Here is a simple Prolog program saved in a file named family.pl male(albert). %a fact stating albert is a male male(edward). female(alice). %a fact stating alice is a female female(victoria). parent(albert,edward). %a fact: albert is parent of edward parent(victoria,edward). father(X,Y) :- %a rule: X is father of Y if X if a male parent of Y parent(X,Y), male(X). %body of above rule, can be on same line. mother(X,Y) :- parent(X,Y), female(X). %a similar rule for X being mother of Y A fact/rule (statement) ends with “.” and white space ignored read :- after rule head as “if”. -
An Architecture for Making Object-Oriented Systems Available from Prolog
An Architecture for Making Object-Oriented Systems Available from Prolog Jan Wielemaker and Anjo Anjewierden Social Science Informatics (SWI), University of Amsterdam, Roetersstraat 15, 1018 WB Amsterdam, The Netherlands, {jan,anjo}@swi.psy.uva.nl August 2, 2002 Abstract It is next to impossible to develop real-life applications in just pure Prolog. With XPCE [5] we realised a mechanism for integrating Prolog with an external object-oriented system that turns this OO system into a natural extension to Prolog. We describe the design and how it can be applied to other external OO systems. 1 Introduction A wealth of functionality is available in object-oriented systems and libraries. This paper addresses the issue of how such libraries can be made available in Prolog, in particular libraries for creating user interfaces. Almost any modern Prolog system can call routines in C and be called from C (or other impera- tive languages). Also, most systems provide ready-to-use libraries to handle network communication. These primitives are used to build bridges between Prolog and external libraries for (graphical) user- interfacing (GUIs), connecting to databases, embedding in (web-)servers, etc. Some, especially most GUI systems, are object-oriented (OO). The rest of this paper concentrates on GUIs, though the argu- ments apply to other systems too. GUIs consist of a large set of entities such as windows and controls that define a large number of operations. These operations often involve destructive state changes and the behaviour of GUI components normally involves handling spontaneous input in the form of events. OO techniques are very well suited to handle this complexity. -
On the Implementation of a Cloud-Based Computing Test Bench Environment for Prolog Systems †
information Article On the Implementation of a Cloud-Based Computing Test Bench Environment for Prolog Systems † Ricardo Gonçalves, Miguel Areias * ID and Ricardo Rocha ID CRACS & INESC TEC and Faculty of Sciences, University of Porto, Rua do Campo Alegre, 1021/1055, 4169-007 Porto, Portugal; [email protected] (R.G.); [email protected] (R.R.) * Correspondence: [email protected] † This paper is an extended version of our paper published in the Symposium on Languages, Applications and Technologies 2017. Received: 13 September 2017; Accepted: 13 October 2017; Published: 19 October 2017 Abstract: Software testing and benchmarking are key components of the software development process. Nowadays, a good practice in large software projects is the continuous integration (CI) software development technique. The key idea of CI is to let developers integrate their work as they produce it, instead of performing the integration at the end of each software module. In this paper, we extend a previous work on a benchmark suite for the YAP Prolog system, and we propose a fully automated test bench environment for Prolog systems, named Yet Another Prolog Test Bench Environment (YAPTBE), aimed to assist developers in the development and CI of Prolog systems. YAPTBE is based on a cloud computing architecture and relies on the Jenkins framework as well as a new Jenkins plugin to manage the underlying infrastructure. We present the key design and implementation aspects of YAPTBE and show its most important features, such as its graphical user interface (GUI) and the automated process that builds and runs Prolog systems and benchmarks. -
Concepts in Programming Languages Practicalities
Concepts in Programming Languages Practicalities I Course web page: Alan Mycroft1 www.cl.cam.ac.uk/teaching/1617/ConceptsPL/ with lecture slides, exercise sheet and reading material. These slides play two roles – both “lecture notes" and “presentation material”; not every slide will be lectured in Computer Laboratory detail. University of Cambridge I There are various code examples (particularly for 2016–2017 (Easter Term) JavaScript and Java applets) on the ‘materials’ tab of the course web page. I One exam question. www.cl.cam.ac.uk/teaching/1617/ConceptsPL/ I The syllabus and course has changed somewhat from that of 2015/16. I would be grateful for comments on any remaining ‘rough edges’, and for views on material which is either over- or under-represented. 1Acknowledgement: various slides are based on Marcelo Fiore’s 2013/14 course. Alan Mycroft Concepts in Programming Languages 1 / 237 Alan Mycroft Concepts in Programming Languages 2 / 237 Main books Context: so many programming languages I J. C. Mitchell. Concepts in programming languages. Cambridge University Press, 2003. Peter J. Landin: “The Next 700 Programming Languages”, I T.W. Pratt and M. V.Zelkowitz. Programming Languages: CACM (published in 1966!). Design and implementation (3RD EDITION). Some programming-language ‘family trees’ (too big for slide): Prentice Hall, 1999. http://www.oreilly.com/go/languageposter http://www.levenez.com/lang/ ? M. L. Scott. Programming language pragmatics http://rigaux.org/language-study/diagram.html (4TH EDITION). http://www.rackspace.com/blog/ Elsevier, 2016. infographic-evolution-of-computer-languages/ I R. Harper. Practical Foundations for Programming Plan of this course: pick out interesting programming-language Languages. -
Java Terms/Concepts You Should Know from OOPDA Glossary Terms
Java Terms/Concepts You Should Know from OOPDA A abstract class A class with the abstract reserved word in its header. Abstract classes are distinguished by the fact that you may not directly construct objects from them using the new operator. An abstract class may have zero or more abstract methods. abstract method A method with the abstract reserved word in its header. An abstract method has no method body. Methods defined in an interface are always abstract. The body of an abstract method must be defined in a sub class of an abstract class, or the body of a class implementing an interface. Abstract Windowing Toolkit The Abstract Windowing Toolkit (AWT) provides a collection of classes that simplify the creation of applications with graphical user interfaces. These are to be found in the java.awt packages. Included are classes for windows, frames, buttons, menus, text areas, and so on. Related to the AWT classes are those for the Swing packages. aggregation A relationship in which an object contains one or more other subordinate objects as part of its state. The subordinate objects typically have no independent existence separate from their containing object. When the containing object has no further useful existence, neither do the subordinate objects. For instance, a gas station object might contain several pump objects. These pumps will only exist as long as the station does. Aggregation is also referred to as the has-a relationship, to distinguish it from the is-a relationship, which refers to inheritance. anonymous class A class created without a class name.