Pharo by Example
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Traits: Experience with a Language Feature
7UDLWV([SHULHQFHZLWKD/DQJXDJH)HDWXUH (PHUVRQ50XUSK\+LOO $QGUHZ3%ODFN 7KH(YHUJUHHQ6WDWH&ROOHJH 2*,6FKRRORI6FLHQFH1(QJLQHHULQJ$ (YHUJUHHQ3DUNZD\1: 2UHJRQ+HDOWKDQG6FLHQFH8QLYHUVLW\ 2O\PSLD$:$ 1::DONHU5G PXUHPH#HYHUJUHHQHGX %HDYHUWRQ$25 EODFN#FVHRJLHGX ABSTRACT the desired semantics of that method changes, or if a bug is This paper reports our experiences using traits, collections of found, the programmer must track down and fix every copy. By pure methods designed to promote reuse and understandability reusing a method, behavior can be defined and maintained in in object-oriented programs. Traits had previously been used to one place. refactor the Smalltalk collection hierarchy, but only by the crea- tors of traits themselves. This experience report represents the In object-oriented programming, inheritance is the normal way first independent test of these language features. Murphy-Hill of reusing methods—classes inherit methods from other classes. implemented a substantial multi-class data structure called ropes Single inheritance is the most basic and most widespread type of that makes significant use of traits. We found that traits im- inheritance. It allows methods to be shared among classes in an proved understandability and reduced the number of methods elegant and efficient way, but does not always allow for maxi- that needed to be written by 46%. mum reuse. Consider a small example. In Squeak [7], a dialect of Smalltalk, Categories and Subject Descriptors the class &ROOHFWLRQ is the superclass of all the classes that $UUD\ +HDS D.2.3 [Programming Languages]: Coding Tools and Tech- implement collection data structures, including , , 6HW niques - object-oriented programming and . The property of being empty is common to many ob- jects—it simply requires that the object have a size method, and D.3.3 [Programming Languages]: Language Constructs and that the method returns zero. -
Liste Von Programmiersprachen
www.sf-ag.com Liste von Programmiersprachen A (1) A (21) AMOS BASIC (2) A# (22) AMPL (3) A+ (23) Angel Script (4) ABAP (24) ANSYS Parametric Design Language (5) Action (25) APL (6) Action Script (26) App Inventor (7) Action Oberon (27) Applied Type System (8) ACUCOBOL (28) Apple Script (9) Ada (29) Arden-Syntax (10) ADbasic (30) ARLA (11) Adenine (31) ASIC (12) Agilent VEE (32) Atlas Transformatikon Language (13) AIMMS (33) Autocoder (14) Aldor (34) Auto Hotkey (15) Alef (35) Autolt (16) Aleph (36) AutoLISP (17) ALGOL (ALGOL 60, ALGOL W, ALGOL 68) (37) Automatically Programmed Tools (APT) (18) Alice (38) Avenue (19) AML (39) awk (awk, gawk, mawk, nawk) (20) Amiga BASIC B (1) B (9) Bean Shell (2) B-0 (10) Befunge (3) BANCStar (11) Beta (Programmiersprache) (4) BASIC, siehe auch Liste der BASIC-Dialekte (12) BLISS (Programmiersprache) (5) Basic Calculator (13) Blitz Basic (6) Batch (14) Boo (7) Bash (15) Brainfuck, Branfuck2D (8) Basic Combined Programming Language (BCPL) Stichworte: Hochsprachenliste Letzte Änderung: 27.07.2016 / TS C:\Users\Goose\Downloads\Softwareentwicklung\Hochsprachenliste.doc Seite 1 von 7 www.sf-ag.com C (1) C (20) Cluster (2) C++ (21) Co-array Fortran (3) C-- (22) COBOL (4) C# (23) Cobra (5) C/AL (24) Coffee Script (6) Caml, siehe Objective CAML (25) COMAL (7) Ceylon (26) Cω (8) C for graphics (27) COMIT (9) Chef (28) Common Lisp (10) CHILL (29) Component Pascal (11) Chuck (Programmiersprache) (30) Comskee (12) CL (31) CONZEPT 16 (13) Clarion (32) CPL (14) Clean (33) CURL (15) Clipper (34) Curry (16) CLIPS (35) -
Basic Structures: Sets, Functions, Sequences, and Sums 2-2
CHAPTER Basic Structures: Sets, Functions, 2 Sequences, and Sums 2.1 Sets uch of discrete mathematics is devoted to the study of discrete structures, used to represent discrete objects. Many important discrete structures are built using sets, which 2.2 Set Operations M are collections of objects. Among the discrete structures built from sets are combinations, 2.3 Functions unordered collections of objects used extensively in counting; relations, sets of ordered pairs that represent relationships between objects; graphs, sets of vertices and edges that connect 2.4 Sequences and vertices; and finite state machines, used to model computing machines. These are some of the Summations topics we will study in later chapters. The concept of a function is extremely important in discrete mathematics. A function assigns to each element of a set exactly one element of a set. Functions play important roles throughout discrete mathematics. They are used to represent the computational complexity of algorithms, to study the size of sets, to count objects, and in a myriad of other ways. Useful structures such as sequences and strings are special types of functions. In this chapter, we will introduce the notion of a sequence, which represents ordered lists of elements. We will introduce some important types of sequences, and we will address the problem of identifying a pattern for the terms of a sequence from its first few terms. Using the notion of a sequence, we will define what it means for a set to be countable, namely, that we can list all the elements of the set in a sequence. -
The Future: the Story of Squeak, a Practical Smalltalk Written in Itself
Back to the future: the story of Squeak, a practical Smalltalk written in itself Dan Ingalls, Ted Kaehler, John Maloney, Scott Wallace, and Alan Kay [Also published in OOPSLA ’97: Proc. of the 12th ACM SIGPLAN Conference on Object-oriented Programming, 1997, pp. 318-326.] VPRI Technical Report TR-1997-001 Viewpoints Research Institute, 1209 Grand Central Avenue, Glendale, CA 91201 t: (818) 332-3001 f: (818) 244-9761 Back to the Future The Story of Squeak, A Practical Smalltalk Written in Itself by Dan Ingalls Ted Kaehler John Maloney Scott Wallace Alan Kay at Apple Computer while doing this work, now at Walt Disney Imagineering 1401 Flower Street P.O. Box 25020 Glendale, CA 91221 [email protected] Abstract Squeak is an open, highly-portable Smalltalk implementation whose virtual machine is written entirely in Smalltalk, making it easy to debug, analyze, and change. To achieve practical performance, a translator produces an equivalent C program whose performance is comparable to commercial Smalltalks. Other noteworthy aspects of Squeak include: a compact object format that typically requires only a single word of overhead per object; a simple yet efficient incremental garbage collector for 32-bit direct pointers; efficient bulk- mutation of objects; extensions of BitBlt to handle color of any depth and anti-aliased image rotation and scaling; and real-time sound and music synthesis written entirely in Smalltalk. Overview Squeak is a modern implementation of Smalltalk-80 that is available for free via the Internet, at http://www.research.apple.com/research/proj/learning_concepts/squeak/ and other sites. It includes platform-independent support for color, sound, and image processing. -
Introduction
Introduction A need shared by many applications is the ability to authenticate a user and then bind a set of permissions to the user which indicate what actions the user is permitted to perform (i.e. authorization). A LocalSystem may have implemented it's own authentication and authorization and now wishes to utilize a federated Identity Provider (IdP). Typically the IdP provides an assertion with information describing the authenticated user. The goal is to transform the IdP assertion into a LocalSystem token. In it's simplest terms this is a data transformation which might include: • renaming of data items • conversion to a different format • deletion of data • addition of data • reorganization of data There are many ways such a transformation could be implemented: 1. Custom site specific code 2. Scripts written in a scripting language 3. XSLT 4. Rule based transforms We also desire these goals for the transformation. 1. Site administrator configurable 2. Secure 3. Simple 4. Extensible 5. Efficient Implementation choice 1, custom written code fails goals 1, 3 and 4, an admin cannot adapt it, it's not simple, and it's likely to be difficult to extend. Implementation choice 2, script based transformations have a lot of appeal. Because one has at their disposal the full power of an actual programming language there are virtually no limitations. If it's a popular scripting language an administrator is likely to already know the language and might be able to program a new transformation or at a minimum tweak an existing script. Forking out to a script interpreter is inefficient, but it's now possible to embed script interpreters in the existing application. -
Type Feedback for Bytecode Interpreters Position Paper ICOOOLPS 2007
Type Feedback for Bytecode Interpreters Position Paper ICOOOLPS 2007 Michael Haupt1, Robert Hirschfeld1, and Marcus Denker2 1 Software Architecture Group Hasso-Plattner-Institut University of Potsdam, Germany 2 Software Composition Group Institute of Computer Science and Applied Mathematics University of Berne, Switzerland michael.haupt,hirschfeld @hpi.uni-potsdam.de, [email protected] { } Abstract. This position paper proposes the exploitation of type feed- back mechanisms, or more precisely, polymorphic inline caches, for purely interpreting implementations of object-oriented programming languages. Using Squeak’s virtual machine as an example, polymorphic inline caches are discussed as an alternative to global caching. An implementation proposal for polymorphic inline caches in the Squeak virtual machine is presented, and possible future applications for online optimization are outlined. 1 Introduction Bytecode interpreters are small in size and comparatively easy to implement, but generally execute programs much less efficiently than just-in-time (JIT) compilers. Techniques like threaded interpretation [9, 11, 2] focus on speeding up bytecode interpretation itself, and caching [4, 5, 1] improves the performance of message sends—the most common operation in object-oriented software [7]. It is interesting to observe that, while threading mechanisms are used natu- rally to a varying degree in bytecode interpreter implementations, such systems usually employ only global caching to speed up dynamic method dispatch. A global cache is clearly beneficial with respect to overall performance. Still, it does not provide optimal support for polymorphic message send sites, and it does not allow for exploiting type information (we provide details on these issues in the following section). In our opinion, the employment of polymorphic inline caches (PICs) [5] instead can provide means for achieving significant speedups in bytecode interpreters while exhibiting only a moderate increase in memory footprint and implementation complexity. -
Graphical Interface
Appendix: How to program in Croquet Author: S.M. Wolff Project: Cell-Forum Project Table of Contents Table of Contents .............................................................................................................. 2 Graphical Interface ........................................................................................................... 6 Control structures .............................................................................................................. 9 Testing variables ............................................................................................................... 9 If then else ........................................................................................................................ 10 Switch ............................................................................................................................ 10 While .............................................................................................................................. 10 For .................................................................................................................................. 11 Data structures ............................................................................................................ 12 Ordered Collection ...................................................................................................... 12 Classes, Methods and Shared Variables .................................................................... 13 Packages ..................................................................................................................... -
Sindarin: a Versatile Scripting API for the Pharo Debugger
Sindarin: A Versatile Scripting API for the Pharo Debugger Thomas Dupriez Guillermo Polito Steven Costiou Univ. Lille, CNRS, Centrale Lille, CNRS - UMR 9189 - CRIStAL, Univ. Inria, Univ. Lille, CNRS, Centrale Inria, UMR 9189 - CRIStAL Lille, Centrale Lille, Inria Lille, UMR 9189 - CRIStAL France France France [email protected] [email protected] [email protected] Vincent Aranega Stéphane Ducasse Univ. Lille, CNRS, Centrale Lille, Inria, Univ. Lille, CNRS, Centrale Inria, UMR 9189 - CRIStAL Lille, UMR 9189 - CRIStAL France France [email protected] [email protected] Abstract Studies and work on debugging acknowledge that main- Debugging is one of the most important and time consuming stream debuggers are not well adapted to several debugging activities in software maintenance, yet mainstream debuggers scenarios [3, 27, 31]. This has led to the appearance of new de- are not well-adapted to several debugging scenarios. This bugging techniques proposing to augment traditional interac- has led to the research of new techniques covering specific tive debuggers with, e.g., stateful breakpoints [4], control-flow families of complex bugs. Notably, recent research proposes aware breakpoints [5], object-centric breakpoints [10, 34], the to empower developers with scripting DSLs, plugin-based and automatic insertion of breakpoints based on dynamic execu- moldable debuggers. However, these solutions are tailored to tions [45], or declarative statements from the developer [21]. specific use-cases, or too costly for one-time-use scenarios. A line of research has also started to study scripting APIs to In this paper we argue that exposing a debugging scripting empower developers to implement debugging scripts adapted interface in mainstream debuggers helps in solving many chal- to their needs. -
2008 Chevrolet Cobalt Owner Manual M
2008 Chevrolet Cobalt Owner Manual M Seats and Restraint Systems ........................... 1-1 Driving Your Vehicle ....................................... 4-1 Front Seats ............................................... 1-2 Your Driving, the Road, and Your Vehicle ..... 4-2 Rear Seats ............................................... 1-9 Towing ................................................... 4-32 Safety Belts ............................................. 1-10 Service and Appearance Care .......................... 5-1 Child Restraints ....................................... 1-30 Service ..................................................... 5-3 Airbag System ......................................... 1-53 Fuel ......................................................... 5-5 Restraint System Check ............................ 1-68 Checking Things Under the Hood ............... 5-10 Features and Controls ..................................... 2-1 Headlamp Aiming ..................................... 5-39 Keys ........................................................ 2-3 Bulb Replacement .................................... 5-42 Doors and Locks ...................................... 2-10 Windshield Wiper Blade Replacement ......... 5-48 Windows ................................................. 2-15 Tires ...................................................... 5-49 Theft-Deterrent Systems ............................ 2-18 Appearance Care ..................................... 5-95 Starting and Operating Your Vehicle ........... 2-21 Vehicle Identification -
MVC Revival on the Web
MVC Revival on the Web Janko Mivšek [email protected] @mivsek @aidaweb ESUG 2013 Motivation 30 years of Smalltalk, 30 years of MVC 34 years exa!tly, sin!e "#$# %ot in JavaScri&t MVC frameworks 'or Sin(le)*age and +ealtime web a&&s ,e Smalltalkers s-ould respe!t and revive our &earls better Contents MVC e &lained %istory /sa(e in !.rrent JavaScri&t frameworks /sa(e in Smalltalk C.rrent and f.t.re MVC in 0ida/Web MVC Explained events Ar!hite!tural desi(n &attern - Model for domain s&e!ifi! data and logi! View updates Controller ) View for &resentation to t-e .ser ) Controller for intera!tions wit- t-e .ser UI and .&datin( domain model Domain changes Main benefit: actions observing ) se&aration of !on!erns Model MVC based on Observer pattern subscribe ) 3bserver looks at observee Observer changed - 3bservee is not aware of t-at s u 4e&enden!y me!-anism2 B t n - 3bserver is de&endent on 3bservee state e observing v - 3bservee m.st re&ort state !-an(es to 3bserver E b - *.b/S.b Event 6.s de!ou&les 3bservee from u S / 3bserver to &reserve its .nawarnes of observation b u changed P Observee Main benefit: (Observable) ) se&aration of !on!erns Multiple observers subscribe - M.lti&le observers of t-e same 3bservee Observer changed - 7n MVC an 3bservee is View and 3bservee is domain Model, t-erefore2 s u B t - many views of t-e same model n e observing v - many a&&s E b - many .sers u S / - mix of all t-ree !ases b u Observee changed P (Observable) Example: Counter demo in Aida/Web M.lti.ser realtime web !ounter exam&le -ttp://demo.aidaweb.si – !li!k Realtime on t-e left – !li!k De!rease or In!rease to c-an(e counter – !ounter is c-an(ed on all ot-er8s browsers History of MVC (1) 7nvented by 9rygve +eenska.g w-en -e worked in "#$:1$# wit- Alan ;ay's group on <ero *arc on Smalltalk and Dynabook – 'inal term Model)View)Controller !oined 10. -
Pharo by Example
Pharo by Example Andrew P. Black Stéphane Ducasse Oscar Nierstrasz Damien Pollet with Damien Cassou and Marcus Denker Version of 2009-10-11 ii This book is available as a free download from http://PharoByExample.org. Copyright © 2007, 2008, 2009 by Andrew P. Black, Stéphane Ducasse, Oscar Nierstrasz and Damien Pollet. The contents of this book are protected under Creative Commons Attribution-ShareAlike 3.0 Unported license. You are free: to Share — to copy, distribute and transmit the work to Remix — to adapt the work Under the following conditions: Attribution. You must attribute the work in the manner specified by the author or licensor (but not in any way that suggests that they endorse you or your use of the work). Share Alike. If you alter, transform, or build upon this work, you may distribute the resulting work only under the same, similar or a compatible license. • For any reuse or distribution, you must make clear to others the license terms of this work. The best way to do this is with a link to this web page: creativecommons.org/licenses/by-sa/3.0/ • Any of the above conditions can be waived if you get permission from the copyright holder. • Nothing in this license impairs or restricts the author’s moral rights. Your fair dealing and other rights are in no way affected by the above. This is a human-readable summary of the Legal Code (the full license): creativecommons.org/licenses/by-sa/3.0/legalcode Published by Square Bracket Associates, Switzerland. http://SquareBracketAssociates.org ISBN 978-3-9523341-4-0 First Edition, October, 2009. -
Dynamic Object-Oriented Programming with Smalltalk
Dynamic Object-Oriented Programming with Smalltalk 1. Introduction Prof. O. Nierstrasz Autumn Semester 2009 LECTURE TITLE What is surprising about Smalltalk > Everything is an object > Everything happens by sending messages > All the source code is there all the time > You can't lose code > You can change everything > You can change things without restarting the system > The Debugger is your Friend © Oscar Nierstrasz 2 ST — Introduction Why Smalltalk? > Pure object-oriented language and environment — “Everything is an object” > Origin of many innovations in OO development — RDD, IDE, MVC, XUnit … > Improves on many of its successors — Fully interactive and dynamic © Oscar Nierstrasz 1.3 ST — Introduction What is Smalltalk? > Pure OO language — Single inheritance — Dynamically typed > Language and environment — Guiding principle: “Everything is an Object” — Class browser, debugger, inspector, … — Mature class library and tools > Virtual machine — Objects exist in a persistent image [+ changes] — Incremental compilation © Oscar Nierstrasz 1.4 ST — Introduction Smalltalk vs. C++ vs. Java Smalltalk C++ Java Object model Pure Hybrid Hybrid Garbage collection Automatic Manual Automatic Inheritance Single Multiple Single Types Dynamic Static Static Reflection Fully reflective Introspection Introspection Semaphores, Some libraries Monitors Concurrency Monitors Categories, Namespaces Packages Modules namespaces © Oscar Nierstrasz 1.5 ST — Introduction Smalltalk: a State of Mind > Small and uniform language — Syntax fits on one sheet of paper >