Object-Oriented and Concurrent Program Design Issues in Ada 95
Total Page:16
File Type:pdf, Size:1020Kb
Load more
Recommended publications
-
Introduction Code Reuse
The Sather Language: Efficient, Interactive, Object-Oriented Programming Stephen Omohundro Dr. Dobbs Journal Introduction Sather is an object oriented language which aims to be simple, efficient, interactive, safe, and non-proprietary. One way of placing it in the "space of languages" is to say that it aims to be as efficient as C, C++, or Fortran, as elegant and safe as Eiffel or CLU, and to support interactive programming and higher-order functions as well as Common Lisp, Scheme, or Smalltalk. Sather has parameterized classes, object-oriented dispatch, statically-checked strong typing, separate implementation and type inheritance, multiple inheritance, garbage collection, iteration abstraction, higher-order routines and iters, exception handling, constructors for arbitrary data structures, and assertions, preconditions, postconditions, and class invariants. This article describes the first few of these features. The development environment integrates an interpreter, a debugger, and a compiler. Sather programs can be compiled into portable C code and can efficiently link with C object files. Sather has a very unrestrictive license which allows its use in proprietary projects but encourages contribution to the public library. The original 0.2 version of the Sather compiler and tools was made available in June 1991. This article describes version 1.0. By the time the article appears, the combined 1.0 compiler/interpreter/debugger should be available on "ftp.icsi.berkeley.edu" and the newsgroup "comp.lang.sather" should be activated for discussion. Code Reuse The primary benefit promised by object-oriented languages is reuse of code. Sather programs consist of collections of modules called "classes" which encapsulate well-defined abstractions. -
CLOS, Eiffel, and Sather: a Comparison
CLOS, Eiffel, and Sather: A Comparison Heinz W. Schmidt-, Stephen M. Omohundrot " September, 1991 li ____________T_R_._91_-0_47____________~ INTERNATIONAL COMPUTER SCIENCE INSTITUTE 1947 Center Street, Suite 600 Berkeley, California 94704-1105 CLOS, Eiffel, and Sather: A Comparison Heinz W. Schmidt-, Stephen M. Omohundrot September, 1991 Abstract The Common Lisp Object System defines a powerful and flexible type system that builds on more than fifteen years of experience with object-oriented programming. Most current implementations include a comfortable suite of Lisp support tools in cluding an Emacs Lisp editor, an interpreter, an incremental compiler, a debugger, and an inspector that together promote rapid prototyping and design. What else might one want from a system? We argue that static typing yields earlier error detec tion, greater robustness, and higher efficiency and that greater simplicity and more orthogonality in the language constructs leads to a shorter learning curve and more in tuitive programming. These elements can be found in Eiffel and a new object-oriented language, Sather, that we are developing at leS!. Language simplicity and static typ ing are not for free,·though. Programmers have to pay with loss of polymorphism and flexibility in prototyping. We give a short comparison of CLOS, Eiffel and Sather, addressing both language and environment issues. The different approaches taken by the languages described in this paper have evolved to fulfill different needs. While we have only touched on the essential differ ences, we hope that this discussion will be helpful in understanding the advantages and disadvantages of each language. -ICSI, on leave from: Inst. f. Systemtechnik, GMD, Germany tICSI 1 Introduction Common Lisp [25] was developed to consolidate the best ideas from a long line of Lisp systems and has become an important standard. -
Iterable Abstract Pattern Matching for Java
JMatch: Iterable Abstract Pattern Matching for Java Jed Liu and Andrew C. Myers Computer Science Department Cornell University, Ithaca, New York Abstract. The JMatch language extends Java with iterable abstract pattern match- ing, pattern matching that is compatible with the data abstraction features of Java and makes iteration abstractions convenient. JMatch has ML-style deep pattern matching, but patterns can be abstract; they are not tied to algebraic data con- structors. A single JMatch method may be used in several modes; modes may share a single implementation as a boolean formula. Modal abstraction simplifies specification and implementation of abstract data types. This paper describes the JMatch language and its implementation. 1 Introduction Object-oriented languages have become a dominant programming paradigm, yet they still lack features considered useful in other languages. Functional languages offer expressive pattern matching. Logic programming languages provide powerful mech- anisms for iteration and backtracking. However, these useful features interact poorly with the data abstraction mechanisms central to object-oriented languages. Thus, ex- pressing some computations is awkward in object-oriented languages. In this paper we present the design and implementation of JMatch, a new object- oriented language that extends Java [GJS96] with support for iterable abstract pattern matching—a mechanism for pattern matching that is compatible with the data abstrac- tion features of Java and that makes iteration abstractions more convenient. -
Concepts in Programming Languages
Concepts in Programming Languages Alan Mycrofta Computer Laboratory University of Cambridge 2014–2015 (Easter Term) http://www.cl.cam.ac.uk/teaching/1415/ConceptsPL/ aNotes largely due to Marcelo Fiore—but errors are my responsibility. 1 Practicalities Course web page: www.cl.cam.ac.uk/teaching/1415/ConceptsPL/ with lecture slides, exercise sheet, and reading material. One exam question. 2 Main books J. C. Mitchell. Concepts in programming languages. Cambridge University Press, 2003. T.W. Pratt and M. V.Zelkowitz. Programming Languages: Design and implementation (3RD EDITION). Prentice Hall, 1999. ⋆ M. L. Scott. Programming language pragmatics (2ND EDITION). Elsevier, 2006. R. Harper. Practical Foundations for Programming Languages. Cambridge University Press, 2013. 3 Context : so many programming languages Peter J. Landin: “The Next 700 Programming Languages”, CACM >>>>1966<<<<. Some programming-language ‘family trees’ (too big for slide): http://www.oreilly.com/go/languageposter http://www.levenez.com/lang/ http://rigaux.org/language-study/diagram.html http://www.rackspace.com/blog/ infographic-evolution-of-computer-languages/ Plan of this course: pick out interesting programming- language concepts and major evolutionary trends. 4 Topics I. Introduction and motivation. II. The first procedural language: FORTRAN (1954–58). III. The first declarative language: LISP (1958–62). IV. Block-structured procedural languages: Algol (1958–68), Pascal (1970). V. Object-oriented languages — Concepts and origins: Simula (1964–67), Smalltalk (1971–80). VI. Languages for concurrency and parallelism. VII. Types in programming languages: ML (1973–1978). VIII. Data abstraction and modularity: SML Modules (1984–97). IX. A modern language design: Scala (2007) X. Miscellaneous concepts 5 Topic I Introduction and motivation References: g g Chapter 1 of Concepts in programming languages by J. -
The Australian National University Object Test Coverage Using Finite
The Australian National University TR-CS-95-06 Object Test Coverage Using Finite State Machines Oscar Bosman and Heinz W. Schmidt September 1995 Joint Computer Science Technical Report Series Department of Computer Science Faculty of Engineering and Information Technology Computer Sciences Laboratory Research School of Information Sciences and Engineering This technical report series is published jointly by the Department of Computer Science, Faculty of Engineering and Information Technology, and the Computer Sciences Laboratory, Research School of Information Sciences and Engineering, The Australian National University. Please direct correspondence regarding this series to: Technical Reports Department of Computer Science Faculty of Engineering and Information Technology The Australian National University Canberra ACT 0200 Australia or send email to: [email protected] A list of technical reports, including some abstracts and copies of some full reports may be found at: http://cs.anu.edu.au/techreports/ Recent reports in this series: TR-CS-95-05 Jeffrey X. Yu, Kian-Lee Tan, and Xun Qu. On balancing workload in a highly mobile environment. August 1995. TR-CS-95-04 Department of Computer Science. Annual report 1994. August 1995. TR-CS-95-03 Douglas R. Sweet and Richard P. Brent. Error analysis of a partial pivoting method for structured matrices. June 1995. TR-CS-95-02 Jeffrey X. Yu and Kian-Lee Tan. Scheduling issues in partitioned temporal join. May 1995. TR-CS-95-01 Craig Eldershaw and Richard P. Brent. Factorization of large integers on some vector and parallel computers. January 1995. TR-CS-94-10 John N. Zigman and Peiyi Tang. -
Sather 1.0 Tutorial
INTERNATIONAL COMPUTER SCIENCE INSTITUTE Center St Suite BerkeleyCalifornia FAX I Sather Tutorial Michael Philippsen phlipp icsib erkeleyedu TR Version Decemb er Abstract This do cumentprovides basic information on how to obtain your copy of the Sather system and gives several p ointers to articles discussing Sather in more detail We thoroughly describ e the implementation of a basic chess program By carefully reading this do cument and the discussed example program you will learn enough ab out Sather to start programming in Sather yourself This do cumentis intended for programmers familiar with ob ject oriented languages such as Eiel or C General information on ob ject oriented programming can b e found in The main features of Sather are explained in detail wecover the dierence between subtyping and implementation inheritance and explain the implementation and usage of iters Moreover the example program intro duces all the class elements constants shared and ob ject attributes routines and iters are intro duced Most statements and most expressions are also discussed Where appropriate the usage of some basic features which are provided by the Sather libraries are demonstrated The Tutorial is completed by showing how an external class can b e used to interface to a C program On leave from Department of Computer Science University of Karlsruhe Germany Contents Ab out Sather Where can I nd Sather Where can I read ab out Sather Related Work SatherK Planned Changes to this Tutorial -
Programming with Assertions: a Prospectus
Assertions can help improve software quality. To use them effectively, it’s important to determine when they are valid. Brian A. Malloy and Jeffrey M. Voas SOFTWARE DEVELOPMENT Programming with Assertions: A Prospectus recent report states that after five Tech., May 2002). With all these hurdles, it’s no decades of software development, wonder why practitioners are looking for alterna- defective software is the norm, high- tives to testing. quality software the exception (“50 AYears of Software: Key Principles for Quality,” ONE ALTERNATIVE: ASSERTIONS J.A. Whittaker and J.M. Voas, IT Professional, An alternative to testing that has increasing pop- Nov.-Dec. 2002, pp. 28-35).This is a disappointing ularity and usage entails the use of assertions to observation in view of the many advances that monitor the data attributes of functions or classes. software development has realized, including the Assertions are formal constraints on the behavior emergence of software process improvement and of a software application; Alan Turing originally the adoption of object technology, including a advocated their use in 1950 (“The Emperor’s Old Unified Modeling Language (UML). Clothes,” C. Hoare, Comm.ACM, Feb. 1981): All these advances facilitate the design of object- oriented systems and the development of compo- An early advocate of using assertions in pro- nent-based software.Clearly,to address the quality gramming was none other than Alan Turing him- problem for software, developers need a technol- self. On 24 June 1950 at a conference in ogy that specializes in producing robust software. Cambridge, he gave a short talk entitled One widely used process that supports the con- “Checking a Large Routine” which explains the struction of quality software is testing, which exe- idea with great clarity. -
Revisiting Coroutines
6 Revisiting Coroutines ANA LUCIA´ DE MOURA and ROBERTO IERUSALIMSCHY Catholic University of Rio de Janeiro (PUC–Rio) This article advocates the revival of coroutines as a convenient general control abstraction. After proposing a new classification of coroutines, we introduce the concept of full asymmetric coroutines and provide a precise definition for it through an operational semantics. We then demonstrate that full coroutines have an expressive power equivalent to one-shot continuations and one-shot delimited continuations. We also show that full asymmetric coroutines and one-shot delimited continuations have many similarities, and therefore present comparable benefits. Nevertheless, coroutines are easier implemented and understood, especially in the realm of procedural languages. Categories and Subject Descriptors: D.3.3 [Programming Languages]: Language Constructs and Features—Control structures, coroutines General Terms: Design, Languages Additional Key Words and Phrases: Continuations, generators, multitasking ACM Reference Format: de Moura, A. L. and Ierusalimschy, R. 2009. Revisiting coroutines. ACM Trans. Program. Lang. Syst. 31, 2, Article 6 (February 2009), 31 pages. DOI = 10.1145/1462166.1462167 http:// doi.acm.org/10.1145/1462166.1462167 1. INTRODUCTION The concept of coroutines was introduced in the early 1960’s and constitutes one of the oldest proposals of a general control abstraction. It is attributed to Conway, who described coroutines as “subroutines who act as the master pro- gram,” and implemented this construct to -
The Cecil Language Specification and Rationale Version 3.2
The Cecil Language Specification and Rationale Version 3.2 Craig Chambers and the Cecil Group Department of Computer Science and Engineering University of Washington Box 352350, Seattle, Washington 98195-2350 USA February, 2004 Abstract Cecil is a purely object-oriented language intended to support rapid construction of high-quality, extensible software. Cecil combines multi-methods with a simple classless object model, a kind of dynamic inheritance, modules, and optional static type checking. Instance variables in Cecil are accessed solely through messages, allowing instance variables to be replaced or overridden by methods and vice versa. Cecil’s predicate objects mechanism allows an object to be classified automatically based on its run-time (mutable) state. Cecil’s static type system distinguishes between subtyping and code inheritance, but Cecil enables these two graphs to be described with a single set of declarations, streamlining the common case where the two graphs are parallel. Cecil includes a fairly flexible form of parameterization, including explicitly parameterized objects, types, and methods, as well as implicitly parameterized methods related to the polymorphic functions commonly found in functional languages. By making type declarations optional, Cecil aims to allow mixing of and migration between exploratory and production programming styles. Cecil supports a module mechanism that enables independently-developed subsystems to be encapsulated, allowing them to be type-checked and reasoned about in isolation despite the presence of multi-methods and subclassing. Objects can be extended externally with additional methods and instance variables, often encapsulated in separate modules, supporting a kind of role- based or subject-oriented programming style. This document mixes the specification of the language with discussions of design issues and explanations of the reasoning that led to various design decisions. -
Engineering a Programming Language
.. 209 Engineering a Programming Language: The language design process has been intimately coupled with the design The Type and Class System of Sather ad Implementation of libraries and applications. A particularly demanding ap lllieation is the extensible ICSI connectionist network simulator: ICSIM [24J. examples in this paper are taken from the actual code and structure of Clemens Szyperski, Stephen Omohundro, and Stephan Muter Sather libraries and applications to make them realistic. The design effort continually a balance between the needs of applications and constraints on International Computer Science Institute JIIIguage design, such as simplicity and orthogonality. 1947 Center St, Suite 600 ., One of the most fundamental aspects of the Sather 1.0 design is its type Berkeley, CA 94704 ""em. Earlier versions of the language were strongly typed, but it was not Email: {szyperski, om, murer)@icsLberkeley.edu ,J'088ible to statically check a system for type correctness. Eiffel has tbe same Fax: +1 510643-7684 (5), and attempts to solve it by introducing system-level type-checking This is a conservative system-wide global check. A system which satisfies ebeck will be type safe but many legal programs are rejected. Adding new Abstract. Sather 1.0 is a programming language whose design hill! re to a system can cause previously correct code to become incorrect. sulted from the interplay of many criteria. It attempts to support a , Sather 1.0 solved this and other problems by completely redesigning the powerful object-oriented paradigm without sacrificing either the com putational performance of traditional procedural languages or support t)'pe and class system. -
NIC) NIC Series Volume 27
Publication Series of the John von Neumann Institute for Computing (NIC) NIC Series Volume 27 John von Neumann Institute for Computing (NIC) Jorg¨ Striegnitz and Kei Davis (Eds.) Joint proceedings of the Workshops on Multiparadigm Programming with Object-Oriented Languages (MPOOL’03) Declarative Programming in the Context of Object-Oriented Languages (DP-COOL’03) organized by John von Neumann Institute for Computing in cooperation with the Los Alamos National Laboratory, New Mexico, USA NIC Series Volume 27 ISBN 3-00-016005-1 Die Deutsche Bibliothek – CIP-Cataloguing-in-Publication-Data A catalogue record for this publication is available from Die Deutsche Bibliothek. Publisher: NIC-Directors Distributor: NIC-Secretariat Research Centre J¨ulich 52425 J¨ulich Germany Internet: www.fz-juelich.de/nic Printer: Graphische Betriebe, Forschungszentrum J¨ulich c 2005 by John von Neumann Institute for Computing Permission to make digital or hard copies of portions of this work for personal or classroom use is granted provided that the copies are not made or distributed for profit or commercial advantage and that copies bear this notice and the full citation on the first page. To copy otherwise requires prior specific permission by the publisher mentioned above. NIC Series Volume 27 ISBN 3-00-016005-1 Table of Contents A Static C++ Object-Oriented Programming (SCOOP) Paradigm Mixing Benefits of Traditional OOP and Generic Programming .................... 1 Nicolas Burrus, Alexandre Duret-Lutz, Thierry Geraud,´ David Lesage, Raphael¨ Poss Object-Model Independence via Code Implants........................... 35 Michał Cierniak, Neal Glew, Spyridon Triantafyllis, Marsha Eng, Brian Lewis, James Stichnoth The ConS/* Programming Languages .................................. 49 Matthias M. -
Dynamic Dispatch in Object-Oriented Languages
Dynamic Dispatch in Ob ject-Oriented Languages y Scott Milton and Heinz W. Schmidt TR-CS-94-02 [email protected], [email protected] January 1994 Abstract Dynamic binding in ob ject-oriented languages is p erhaps the most imp ortant semantic asp ect of these languages. At the same time it can contribute to ineciency and lackof robustness b ecause it incurs lo okup overheads on function calls and hinders the compiler determining the exact typ e of ob jects held in variables or returned by functions. This may, for instance, preclude inlining of small functions or attribute o set computation at compile time. Yet attribute accesses are the most frequently executed op erations. As a result, to regain lost p erformance, OO programmers are tempted to break the encapsulation of classes or want explicit control over dynamic dispatch, trading o extensibility. In the implementation of parallel ob ject-oriented languages the additional complication arises that ob ject accesses may require more exp ensive remote memory accesses. Lo okup at the call may b e inappropriate if the co de has to b e executed on a di erent pro cessor and there p erhaps has a di erent address. This pap er summarizes dispatching as addressed in several mo dern ob ject-oriented languages. We then describ e and b enchmark fast and exible dispatchschemes that we are currently implementing on SPARC based workstations and multi-pro cessors. These involve elements of C++ virtual function tables and Ei el's and Sather's ability to rede ne abstract functions as attributes.