Smalltalk Topics History and Significance of Smalltalk Object-Oriented Programming the Best Way to Predict the Future Is to the Smalltalk Language Invent It
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Preview Objective-C Tutorial (PDF Version)
Objective-C Objective-C About the Tutorial Objective-C is a general-purpose, object-oriented programming language that adds Smalltalk-style messaging to the C programming language. This is the main programming language used by Apple for the OS X and iOS operating systems and their respective APIs, Cocoa and Cocoa Touch. This reference will take you through simple and practical approach while learning Objective-C Programming language. Audience This reference has been prepared for the beginners to help them understand basic to advanced concepts related to Objective-C Programming languages. Prerequisites Before you start doing practice with various types of examples given in this reference, I'm making an assumption that you are already aware about what is a computer program, and what is a computer programming language? Copyright & Disclaimer © Copyright 2015 by Tutorials Point (I) Pvt. Ltd. All the content and graphics published in this e-book are the property of Tutorials Point (I) Pvt. Ltd. The user of this e-book can retain a copy for future reference but commercial use of this data is not allowed. Distribution or republishing any content or a part of the content of this e-book in any manner is also not allowed without written consent of the publisher. We strive to update the contents of our website and tutorials as timely and as precisely as possible, however, the contents may contain inaccuracies or errors. Tutorials Point (I) Pvt. Ltd. provides no guarantee regarding the accuracy, timeliness or completeness of our website or its contents including this tutorial. If you discover any errors on our website or in this tutorial, please notify us at [email protected] ii Objective-C Table of Contents About the Tutorial .................................................................................................................................. -
On Goto Statement in Basic
On Goto Statement In Basic James spores his coeditor arrest lowse, but ribbony Clarence never perambulating so defenselessly. orFingered ferniest and after sold grapy Barry Jimmy sublime countermarches his microclimates so thwart? envelop snigs opinionatively. Is Skylar mismatched Download On Goto Statement In Basic pdf. Download On Goto Statement In Basic doc. Well before withthe statement recursion, basic, and look understandable like as labe not, usage i learned of. Normal to that precedence include support that the content goto basic;is a goto. back Provided them up by statementthe adjectives basic, novel the anddim knowsstatement exactly with be the in below. basic doesMany not and supported the active for on the goto vba. in theSkip evil the comes error asfrom on movesthe specified to go toworkbook go with thename _versionname_ to see the value home does page. not Activeprovided on byone this is withinsurvey? different Outline if ofa trailingbasic withinspace theor responding value if by thisto. Repaired page? Print in favor statement of code along so we with need recursion: to go with many the methods product. becomeThought of goto is startthousands running of intothe code?more readable Slightly moreand in instances vb. Definitely that runnot onprovided basic program, by a more goto explicit that construct,exponentiation, basic i moreinterpreter about? jump Stay to thatadd youthe workbookwhen goto name. basic commandPrediction gotoor go used, on statement we were basicnot, same moves page to the returns slightly isresults a boolean specific in toworkbook the trademarks name to of. the Day date is of.another Exactly if you what forgot you runa stack on in overflow basic does but misusingnot complete it will code isgenerally the window. -
7. Control Flow First?
Copyright (C) R.A. van Engelen, FSU Department of Computer Science, 2000-2004 Ordering Program Execution: What is Done 7. Control Flow First? Overview Categories for specifying ordering in programming languages: Expressions 1. Sequencing: the execution of statements and evaluation of Evaluation order expressions is usually in the order in which they appear in a Assignments program text Structured and unstructured flow constructs 2. Selection (or alternation): a run-time condition determines the Goto's choice among two or more statements or expressions Sequencing 3. Iteration: a statement is repeated a number of times or until a Selection run-time condition is met Iteration and iterators 4. Procedural abstraction: subroutines encapsulate collections of Recursion statements and subroutine calls can be treated as single Nondeterminacy statements 5. Recursion: subroutines which call themselves directly or indirectly to solve a problem, where the problem is typically defined in terms of simpler versions of itself 6. Concurrency: two or more program fragments executed in parallel, either on separate processors or interleaved on a single processor Note: Study Chapter 6 of the textbook except Section 7. Nondeterminacy: the execution order among alternative 6.6.2. constructs is deliberately left unspecified, indicating that any alternative will lead to a correct result Expression Syntax Expression Evaluation Ordering: Precedence An expression consists of and Associativity An atomic object, e.g. number or variable The use of infix, prefix, and postfix notation leads to ambiguity An operator applied to a collection of operands (or as to what is an operand of what arguments) which are expressions Fortran example: a+b*c**d**e/f Common syntactic forms for operators: The choice among alternative evaluation orders depends on Function call notation, e.g. -
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. -
Gnu Smalltalk Library Reference Version 3.2.5 24 November 2017
gnu Smalltalk Library Reference Version 3.2.5 24 November 2017 by Paolo Bonzini Permission is granted to copy, distribute and/or modify this document under the terms of the GNU Free Documentation License, Version 1.2 or any later version published by the Free Software Foundation; with no Invariant Sections, with no Front-Cover Texts, and with no Back-Cover Texts. A copy of the license is included in the section entitled \GNU Free Documentation License". 1 3 1 Base classes 1.1 Tree Classes documented in this manual are boldfaced. Autoload Object Behavior ClassDescription Class Metaclass BlockClosure Boolean False True CObject CAggregate CArray CPtr CString CCallable CCallbackDescriptor CFunctionDescriptor CCompound CStruct CUnion CScalar CChar CDouble CFloat CInt CLong CLongDouble CLongLong CShort CSmalltalk CUChar CByte CBoolean CUInt CULong CULongLong CUShort ContextPart 4 GNU Smalltalk Library Reference BlockContext MethodContext Continuation CType CPtrCType CArrayCType CScalarCType CStringCType Delay Directory DLD DumperProxy AlternativeObjectProxy NullProxy VersionableObjectProxy PluggableProxy SingletonProxy DynamicVariable Exception Error ArithmeticError ZeroDivide MessageNotUnderstood SystemExceptions.InvalidValue SystemExceptions.EmptyCollection SystemExceptions.InvalidArgument SystemExceptions.AlreadyDefined SystemExceptions.ArgumentOutOfRange SystemExceptions.IndexOutOfRange SystemExceptions.InvalidSize SystemExceptions.NotFound SystemExceptions.PackageNotAvailable SystemExceptions.InvalidProcessState SystemExceptions.InvalidState -
The Development of Smalltalk Topic Paper #7
The Development of Smalltalk Topic Paper #7 Alex Laird Max Earn Peer CS-3210-01 Reviewer On Time/Format 1 2/4/09 Survey of Programming Languages Correct 5 Spring 2009 Clear 2 Computer Science, (319) 360-8771 Concise 2 [email protected] Grading Rubric Grading Total 10 pts ABSTRACT Dynamically typed languages are easier on the compiler because This paper describes the development of the Smalltalk it has to make fewer passes and the brunt of checking is done on programming language. the syntax of the code. Compilation of Smalltalk is just-in-time compilation, also known Keywords as dynamic translation. It means that upon compilation, Smalltalk code is translated into byte code that is interpreted upon usage and Development, Smalltalk, Programming, Language at that point the interpreter converts the code to machine language and the code is executed. Dynamic translations work very well 1. INTRODUCTION with dynamic typing. Smalltalk, yet another programming language originally developed for educational purposes and now having a much 5. IMPLEMENTATIONS broader horizon, first appeared publically in the computing Smalltalk has been implemented in numerous ways and has been industry in 1980 as a dynamically-typed object-oriented language the influence of many future languages such as Java, Python, based largely on message-passing in Simula and Lisp. Object-C, and Ruby, just to name a few. Athena is a Smalltalk scripting engine for Java. Little Smalltalk 2. EARLY HISTORY was the first interpreter of the programming language to be used Development for Smalltalk started in 1969, but the language outside of the Xerox PARC. -
Smalltalk's Influence on Modern Programming
1 Smalltalk’s Influence on Modern Programming Smalltalk’s Influence on Modern Programming Matt Savona. February 1 st , 2008. In September 1972 at Xerox PARC, Alan Kay, Ted Kaeher and Dan Ingalls were discussing programming languages in the hallway of their office building. Ted and Dan had begun to consider how large a language had to be to have “great power.” Alan took a different approach, and “asserted that you could define the "most powerful language in the world" in "a page of code."” Ted and Dan replied, “Put up or shut up” (Kay). And with that, the bet to develop the most powerful language was on. Alan arrived at PARC every morning at 4am for two weeks, and devoted his time from 4am to 8am to the development of the language. That language was Smalltalk. Kay had “originally made the boast because McCarthy's self-describing LISP interpreter was written in itself. It was about "a page", and as far as power goes, LISP was the whole nine- yards for functional languages.” He was sure that he could “do the same for object-oriented languages” and still have a reasonable syntax. By the eighth morning, Kay had a version of Smalltalk developed where “symbols were byte-coded and the receiving of return-values from a send was symmetric” (Kay). Several days later, Dan Ingalls had coded Kay’s scheme in BASIC, added a “token scanner”, “list maker” and many other features. “Over the next ten years he made at least 80 major releases of various flavors of Smalltalk” (Kay). -
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. -
A Tour of the Squeak Object Engine
A Tour of the Squeak Object Engine A Tour of the Squeak Object Engine Tim Rowledge, [email protected] Introduction This chapter is intended to explain some basics of how a Virtual Machine (VM) works, why a VM is useful, what it does for the Squeak programmer and user, and how the Squeak VM might develop in the future. What is a Virtual Machine and why do we need one? A Virtual Machine provides us with a pretense of being a machine other than the actual hardware in use. Using one allows systems that behave differently than the host hardware to run as if on hardware designed for them. The term Object Engine is less commonly used but is a useful concept that includes the lowest system areas of the langauge environment running on the VM. Since there is often some flux in the definition of which components are within the actual VM and which are part of the supported environment, Object Engine is useful as a more inclusive term. The term Virtual Machine is used in several ways. When IBM refer to VM/CMS they are referring to a way of making a mainframe behave as if it is many machines, so that programs can assume they have total control even though they do not. Intel provide a somewhat similar facility in the x86 architecture(?), referred to as Virtual Mode. This sort of VM is a complete hardware simulation, often supported at the lowest level by the hardware. Another sort of VM is the emulator - SoftWindows for the Mac, Acorn's !PC, Linux's WINE are good examples - where another machine and/or OS is simulated to allow a Mac user to run Windows programs, an Acorn RiscPC or a Linux machine to run Windows98 programs and so on. -
Cross-Language Interop Poster
Low Cognitive Overhead Bridging "Interoperability isn't just a technical problem, it's also a user interface problem. We have to make it easy to call between languages, so that users can The demo shown at FOSDEM always pick the most appropriate tool for the job at hand." example [ this year showed fully dynamic "This shows how to call a C function from Smalltalk" development spanning C objc_setAssociatedObject: { Objective-C and Smalltalk. The self. 42. developer can inspect the ’fishes’. existing class hierarchy and C enumValue: OBJC_ASSOCIATION_ASSIGN }. the code for any methods "Note how C enumerations can be accessed. When encountering this construct, the Pragmatic Smalltalk compiler will generate exactly the same code as an implemented in Smalltalk. It Objective-C compiler would for this line: is also possible to add, modify, objc_setAssociatedObject(self, 42, @"fishes", OBJC_ASSOCIATION_ASSIGN); or replace methods, add It will get the types for the function by parsing the header and automatically map Smalltalk types to C and Objective-C types. The instance variables and classes Easy Development programmer doesn't need to write any bridging or foreign function interface at run time. Invoking a code." nonexistent class or method (C objc_getAssociatedObject: {self . 42 }) log. ] pops up a dialog asking the user to implement it, all from within a running app. The final version is statically compiled, with no explicit user Cross-Language Interoperability for intervention required. Fast, Easy, and Maintainable Code David Chisnall The World Today: But I wanted to use the But libfoo is C, libbar Frobnicator framework, and it's I have a great idea is C++, and I want to only for Java. -
Smalltalk Language Mapping Specification
Smalltalk Language Mapping Specification New Edition: June 1999 Copyright 1995, 1996 BNR Europe Ltd. Copyright 1998, Borland International Copyright 1991, 1992, 1995, 1996 Digital Equipment Corporation Copyright 1995, 1996 Expersoft Corporation Copyright 1996, 1997 FUJITSU LIMITED Copyright 1996 Genesis Development Corporation Copyright 1989, 1990, 1991, 1992, 1995, 1996 Hewlett-Packard Company Copyright 1991, 1992, 1995, 1996 HyperDesk Corporation Copyright 1998 Inprise Corporation Copyright 1996, 1997 International Business Machines Corporation Copyright 1995, 1996 ICL, plc Copyright 1995, 1996 IONA Technologies, Ltd. Copyright 1996, 1997 Micro Focus Limited Copyright 1991, 1992, 1995, 1996 NCR Corporation Copyright 1995, 1996 Novell USG Copyright 1991,1992, 1995, 1996 by Object Design, Inc. Copyright 1991, 1992, 1995, 1996 Object Management Group, Inc. Copyright 1996 Siemens Nixdorf Informationssysteme AG Copyright 1991, 1992, 1995, 1996 Sun Microsystems, Inc. Copyright 1995, 1996 SunSoft, Inc. Copyright 1996 Sybase, Inc. Copyright 1998 Telefónica Investigación y Desarrollo S.A. Unipersonal Copyright 1996 Visual Edge Software, Ltd. The companies listed above have granted to the Object Management Group, Inc. (OMG) a nonexclusive, royalty-free, paid up, worldwide license to copy and distribute this document and to modify this document and distribute copies of the modified ver- sion. Each of the copyright holders listed above has agreed that no person shall be deemed to have infringed the copyright in the included material of any such copyright holder by reason of having used the specification set forth herein or having con- formed any computer software to the specification. PATENT The attention of adopters is directed to the possibility that compliance with or adoption of OMG specifications may require use of an invention covered by patent rights. -
The Cedar Programming Environment: a Midterm Report and Examination
The Cedar Programming Environment: A Midterm Report and Examination Warren Teitelman The Cedar Programming Environment: A Midterm Report and Examination Warren Teitelman t CSL-83-11 June 1984 [P83-00012] © Copyright 1984 Xerox Corporation. All rights reserved. CR Categories and Subject Descriptors: D.2_6 [Software Engineering]: Programming environments. Additional Keywords and Phrases: integrated programming environment, experimental programming, display oriented user interface, strongly typed programming language environment, personal computing. t The author's present address is: Sun Microsystems, Inc., 2550 Garcia Avenue, Mountain View, Ca. 94043. The work described here was performed while employed by Xerox Corporation. XEROX Xerox Corporation Palo Alto Research Center 3333 Coyote Hill Road Palo Alto, California 94304 1 Abstract: This collection of papers comprises a report on Cedar, a state-of-the-art programming system. Cedar combines in a single integrated environment: high-quality graphics, a sophisticated editor and document preparation facility, and a variety of tools for the programmer to use in the construction and debugging of his programs. The Cedar Programming Language is a strongly-typed, compiler-oriented language of the Pascal family. What is especially interesting about the Ce~ar project is that it is one of the few examples where an interactive, experimental programming environment has been built for this kind of language. In the past, such environments have been confined to dynamically typed languages like Lisp and Smalltalk. The first paper, "The Roots of Cedar," describes the conditions in 1978 in the Xerox Palo Alto Research Center's Computer Science Laboratory that led us to embark on the Cedar project and helped to define its objectives and goals.