Bindings, Initialization, Scope, and Lifetime
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CS 403/503: Programming Languages
BNF for <expression> <expression> → identifier | number | CS 403 -<expression> | (<expression>) | <expression><operator><expression> Organization of Programming Languages <operator> → + | - | * | / Class 3 - August 30, 2001 Topics For Today Parse Tree Review of BNF (Chapter 2.1) Derivations and parse trees (Chapter 2.1) Binding time (Chapter 3.1) Object lifetime and storage slope * x + intercept management (Chapter 3.2) BNF Concept Review Another Parse Tree Terminal symbols: Actual items that are part of the language (0,1,+,-,*,/,etc.) Non-Terminal symbols: <expr>, <op>, etc. Rule/production: A single line of BNF Alternatives: Expressed with | Also: slope * x + intercept *: 0 or more occurrences +:1 or more occurrences 1 Binding Lifetimes • Binding lifetime: The period of time Def: A binding is an association, such between the creation and destruction of a as between an attribute and an entity, name-to-object binding • Object lifetime: The period of time or between an operation and a between the creation and destruction of symbol. an object • These don’t necessarily coincide Def: Binding time is the time at which a • EX. Reference parameters binding takes place. Possible binding times Object Lifetimes… 1. Language design time--e.g., bind operator …correspond to one of three principal symbols to operations 2. Language implementation time--e.g., bind fl. pt. storage allocation mechanisms: type to a representation Static objects: Object lifetime = program 3. Compile time--e.g., bind a variable to a type in C execution. Object bound to one storage or Java location from load time on. 4. Load time--e.g., bind a FORTRAN 77 variable to a memory cell (or a C static variable) Stack objects: Object lifetime = subroutine 5. -
Constrained Polymorphic Types for a Calculus with Name Variables∗
Constrained Polymorphic Types for a Calculus with Name Variables∗ Davide Ancona1, Paola Giannini†2, and Elena Zucca3 1 DIBRIS, Università di Genova, via Dodecaneso 35, Genova, Italy [email protected] 2 DISIT, Università del Piemonte Orientale, via Teresa Michel 11, Alessandria, Italy [email protected] 3 DIBRIS, Università di Genova, via Dodecaneso 35, Genova, Italy [email protected] Abstract We extend the simply-typed lambda-calculus with a mechanism for dynamic rebinding of code based on parametric nominal interfaces. That is, we introduce values which represent single fragments, or families of named fragments, of open code, where free variables are associated with names which do not obey α-equivalence. In this way, code fragments can be passed as function arguments and manipulated, through their nominal interface, by operators such as rebinding, overriding and renaming. Moreover, by using name variables, it is possible to write terms which are parametric in their nominal interface and/or in the way it is adapted, greatly enhancing expressivity. However, in order to prevent conflicts when instantiating name variables, the name- polymorphic types of such terms need to be equipped with simple inequality constraints. We show soundness of the type system. 1998 ACM Subject Classification D.3.1 Programming Languages: Formal Definitions and The- ory, D.3.3 Programming Languages: Language Constructs and Features Keywords and phrases open code, incremental rebinding, name polymorphism, metaprogram- ming Digital Object Identifier 10.4230/LIPIcs.TYPES.2015.4 1 Introduction We propose an extension of the simply-typed lambda-calculus with a mechanism for dynamic and incremental rebinding of code based on parametric nominal interfaces. -
C++/CLI Language Specification
Ecma/TC39-TG5/2004/25 C++/CLI Language Specification Working Draft 1.5, Jun, 2004 Public Review Document Text highlighted like this indicates a placeholder for some future action. It might be a note from the editor to himself, or an indication of the actual or expected direction of some as-yet open issue. Note: In the spirit of the "Working Draft, Standard for Programming Language C++", this is an early draft. It’s known to be incomplet and incorrekt, and it has lots of bad formatting. Publication Time: 6/17/2004 11:44 PM Table of Contents Table of Contents Introduction....................................................................................................................................................xi 1. Scope............................................................................................................................................................. 1 2. Conformance ............................................................................................................................................... 2 3. Normative references .................................................................................................................................. 3 4. Definitions .................................................................................................................................................... 4 5. Notational conventions................................................................................................................................ 7 6. Acronyms and abbreviations -
4500/6500 Programming Languages Name, Binding and Scope Binding
Name, Binding and Scope !! A name is exactly what you think it is CSCI: 4500/6500 Programming »! Most names are identifiers Languages »! symbols (like '+') can also be names !! A binding is an association between two things, such as a name and the thing it names Names, Scopes (review) and Binding »! Example: the association of Reflecting on the Concepts –! values with identifiers !! The scope of a binding is the part of the program (textually) in which the binding is active 1 Maria Hybinette, UGA Maria Hybinette, UGA 2 Binding Time Bind Time: Language System View !! When the “binding” is created or, more !! language design time generally, the point at which any »! bind operator symbols (e.g., * + …) to operations implementation decision is made (multiplication, addition, …) »! Set of primitive types »! language design time »! language implementation time !! language implementation time »! bind data type, such as int in C to the range of »! program writing time possible values (determined by number of bits and »! compile time affect the precision) »! link time –! Considerations: arithmetic overflow, precision of fundamental type, coupling of I/O to the OS’ notion of »! load time files »! run time Maria Hybinette, UGA 3 Maria Hybinette, UGA 4 Bind Time: User View Bind Time: User View !! program writing time !! run time (dynamically) »! Programmers choose algorithms, data structures »! value/variable bindings, sizes of strings and names. »! subsumes !! compile time –! program start-up time »! plan for data layout (bind a variable to a data type in –! module entry time Java or C) –! elaboration time (point a which a declaration is first "seen") !! link time –! procedure entry time »! layout of whole program in memory (names of –! block entry time separate modules (libraries) are finalized. -
Naming Service Specification
Naming Service Specification Version 1.0 New edition - April 2000 Copyright 1996, AT&T/Lucent Technologies, Inc. Copyright 1995, 1996 AT&T/NCR Copyright 1995, 1996 BNR Europe Limited Copyright 1996, Cooperative Research Centre for Distributed Systems Technology (DSTC Pty Ltd). Copyright 1995, 1996 Digital Equipment Corporation Copyright 1996, Gradient Technologies, Inc. Copyright 1995, 1996 Groupe Bull Copyright 1995, 1996 Hewlett-Packard Company Copyright 1995, 1996 HyperDesk Corporation Copyright 1995, 1996 ICL plc Copyright 1995, 1996 Ing. C. Olivetti & C.Sp Copyright 1995, 1996 International Business Machines Corporation Copyright 1996, International Computers Limited Copyright 1995, 1996 Iona Technologies Ltd. Copyright 1995, 1996 Itasca Systems, Inc. Copyright 1996, Nortel Limited Copyright 1995, 1996 Novell, Inc. Copyright 1995, 1996 02 Technologies Copyright 1995, 1996 Object Design, Inc. Copyright 1999, Object Management Group, Inc. Copyright 1995, 1996 Objectivity, Inc. Copyright 1995, 1996 Ontos, Inc. Copyright 1995, 1996 Oracle Corporation Copyright 1995, 1996 Persistence Software Copyright 1995, 1996 Servio, Corp. Copyright 1995, 1996 Siemens Nixdorf Informationssysteme AG Copyright 1995, 1996 Sun Microsystems, Inc. Copyright 1995, 1996 SunSoft, Inc. Copyright 1996, Sybase, Inc. Copyright 1996, Taligent, Inc. Copyright 1995, 1996 Tandem Computers, Inc. Copyright 1995, 1996 Teknekron Software Systems, Inc. Copyright 1995, 1996 Tivoli Systems, Inc. Copyright 1995, 1996 Transarc Corporation Copyright 1995, 1996 Versant Object -
A Language Generic Solution for Name Binding Preservation in Refactorings
A Language Generic Solution for Name Binding Preservation in Refactorings Maartje de Jonge Eelco Visser Delft University of Technology Delft University of Technology Delft, Netherlands Delft, Netherlands [email protected] [email protected] ABSTRACT particular problem, since these languages are often devel- The implementation of refactorings for new languages re- oped with fewer resources than general purpose languages. quires considerable effort from the language developer. We Language workbenches aim at reducing that effort by fa- aim at reducing that effort by using language generic tech- cilitating efficient development of IDE support for software niques. This paper focuses on behavior preservation, in languages [18]. Notable examples include MontiCore [27], particular the preservation of static name bindings. To de- EMFText [22], MPS [25], TMF [7], Xtext [14], and our own tect name binding violations, we implement a technique that Spoofax [26]. The Spoofax language workbench generates reuses the name analysis defined in the compiler front end. a complete implementation of an editor plugin with com- Some languages offer the possibility to access variables us- mon syntactic services based on the syntax definition of a ing qualified names. As a refinement to violation detection, language in SDF [35]. Services that require semantic analy- we show that name analysis can be defined as a reusable sis and/or transformation are implemented in the Stratego traversal strategy that can be applied to restore name bind- transformation language [12]. Especially challenging is the ings by creating qualified names. These techniques offer an implementation of refactorings, which are transformations efficient and reliable solution; the semantics of the language that improve the internal structure of a program while pre- is implemented only once, with the compiler being the single serving its behavior. -
C# Programming in Depth Lecture 4: Garbage Collection & Exception
Chair of Software Engineering C# Programming in Depth Prof. Dr. Bertrand Meyer March 2007 – May 2007 Lecture 4: Garbage Collection & Exception Handling Lisa (Ling) Liu Overview Scope and lifetime Garbage collection mechanism Exception handling C# programming lecture 4: Garbage Collection & Exception Handling 2 Scope and lifetime Scope of a variable is portion of program text within which it is declared ¾ Need not be contiguous ¾ In C#, is static: independent of data Lifetime or extent of storage is portion of program execution during which it exists ¾ Always contiguous ¾ Generally dynamic: dependent on data Class of lifetime ¾ Static: entire duration of program ¾ Local or automatic: duration of call or block execution (local variable) ¾ Dynamic: From time of allocation statement (new) to deallocation, if any. C# programming lecture 4: Garbage Collection & Exception Handling 3 Object lifetime in C# Memory allocation for an object should be made using the “new” keyword Objects are allocated onto the managed heap, where they are automatically deallocated by the runtime at “some time in the future” Garbage collection is automated in C# Rule: Allocate an object onto the managed heap using the new keyword and forget about it C# programming lecture 4: Garbage Collection & Exception Handling 4 Object creation When a call to new is made, it creates a CIL “newobj” instruction to the code module public static int Main (string[] args) { Car c = new Car(“Viper”, 200, 100); } IL_000c: newobj instance void CilNew.Car::.ctor (string, int32, -
Generating Object Lifetime Traces with Merlin
Generating Object Lifetime Traces with Merlin MATTHEW HERTZ University of Massachusetts, Amherst STEPHEN M BLACKBURN Australian National University J ELIOT B MOSS University of Massachusetts, Amherst KATHRYN S McKINLEY University of Texas at Austin and DARKO STEFANOVIC´ University of New Mexico ÈÖÓÖÑÑÖ× Ö ÛÖØÒ ÖÔÐÝ ÖÓÛÒ ÒÙÑ Ö Ó ÔÖÓÖÑ× Ò Ó Ø ÐÒÙ׸ × ÂÚ Ò ¸ ØØ ÖÕÙÖ Ö Ö Ò ×ÑÙÐØÓÒ ×Ô ÜÔÐÓÖØÓÒ ÙÔ Ý ÒÐÒ Ô Ö ÙÒÖרÒÒ× Ó Ó ÐØÑ ÚÓÖ Ò Ò ×Ò Ó ÒÛ Ö ÐÓÖØÑ׺ ÏÒ ÒÖØÒ Ô Ø ÖÙØ¹ÓÖ ÑØÓ Ó Ó ÐØÑ× ÖÕÙÖ× ÛÓÐ¹Ô Ö Ø ÚÖÝ Ô ÓØÒØÐ Ô ÓÒØ Ò Ø ÔÖÓÖѺ Ø× ÔÖÓ × ÔÖÓØÚÐÝ ÜÔ Ò×Ú¸ Ö× ÓØÒ ÒÙÐØ Ý ÓÒÐÝ Ô ÖÓ ¸ ºº¸ ÚÖÝ ¿¾Ã ÝØ× Ó ÐÐÓ Ù× Ö Û Ï ÜØÒ Ø ×ØØ Ó Ø ÖØ ÓÖ ×ÑÙÐØÒ Ö ÐÓÖØÑ× Ò ØÛÓÛÝ׺ Öר¸ ÚÐÓÔ ÑØÓ ÓÐÓÝ ÓÖ ×ÑÙÐØÓÒ ×ØÙ× Ó ÝÒ Ö Ò ÔÖ×ÒØ Ö×ÙÐØ× ×ÓÛÒ Ø Ó ÖÒÙÐÖØÝ ÓÒ Ø× ×ÑÙÐØÓÒ׺ Ï ×ÓÛ ØØ ÖÒÙÐÖØÝ ÓØÒ ×ØÓÖØ× ×ÑÙÐØ Ö Ö×ÙÐØ× ÛØ Ô Û ÓÖ Ó ÔÖ×ÒØ Ò Ñ×ÙÖ Ø Ô Ó ÒÛ ÐÓÖØÑ ÅÖÐÒ ÐØÑ׺ ÅÖÐÒ ØÑרÑÔ× Ó Ò ÐØÖ Ù×× Ø ØÑרÑÔ× Ó Ó ØÓ ÛÒ ØÝ º Ì ÅÖÐÒ ÐÓÖØÑ × ÓÒ Ö Ô ÖÓÖÑ Ý Ø × ÖÑÒØÐ Ö×ÙÐØ× ×ÓÛ ØØ ÅÖÐÒ ÒÖØ ÓÚÖ ØÛÓ ÓÖÖ× Ó ÑÒØÙ ×Ý×ØÑº ÜÔ ×ØÖ ØÒ Ø ÑØÓ ØÖ ÚÖÝ Ó ÐÐÓ Ï Ð×Ó Ù× ÅÖÐÒ ØÓ ÔÖÓ Ú×ÙÐÞØÓÒ× Ó Ô ÚÓÖ ØØ ÜÔ Ó× ÒÛ Ó ÐØÑ ÚÓÖ׺ Categories and Subject Descriptors: D.3.4 [Programming Languages]: Processors—memory management (gar- bage collection) ÒÖÐ ÌÖÑ× ÐÓÖØÑ׸ ÄÒÙ׸ È ØÓÒÐ ÃÝ ÏÓÖ× Ò ÈÖ×× Ö ×Ò¸ Ó ÐØÑ ÒÐÝ×׸ ÒÖØÓÒ This work is supported by NSF grants CCR-0219587, ITR CCR-0085792, EIA-0218262, EIA-9726401, EIA- 030609, EIA-0238027, EIA-0324845, DARPA F33615-03-C-4106, Hewlett-Packard gift 88425.1, Microsoft Re- search, and IBM. -
Modern C++ Object-Oriented Programming
CPP Modern C++ Object-Oriented Programming ''Combine old and newer features to get the best out of the language'' Margit ANTAL 2020 C++ - Object-Oriented Programming Course content − Introduction to C++ − Object-oriented programming − Generic programming and the STL − Object-oriented design C++ - Object-Oriented Programming References − Bjarne Stroustrup, Herb Sutter, C++ Core Guidelines, 2017. rd − M. Gregoire, Professional C++, 3 edition, John Wiley & Sons, 2014. th − S. Lippman, J. Lajoie, B. E. Moo, C++ Primer, 5 edition, Addison Wesley, , 2013. th − S. Prata, C++ Primer Plus, 6 edition, Addison Wesley, 2012. − N. Josuttis, The C++ standard library. a tutorial and reference. Pearson Education. 2012. − A. Williams, C++ Concurrency in Action:Practical Multithreading. Greenwich, CT: Manning. 2012. Module 1 Introduction to C++ Introduction to C++ Content − History and evolution − Overview of the key features ● New built-in types ● Scope and namespaces ● Enumerations ● Dynamic memory: new and delete ● Smart pointers: unique_ptr, shared_ptr, weak_ptr ● Error handling with exceptions ● References ● The const modifier Introduction to C++ History and evolution − Creator: Bjarne Stroustrup 1983 − Standards: ● The first C++ standard − 1998 (C++98, major) − 2003 (C++03, minor) ● The second C++ standard − 2011 (C++11, major) – significant improvements in language and library − 2014 (C++14, minor) − 2017 (C++17, major) Introduction to C+ History and evolution − source: https://isocpp.org/std/status Introduction to C+ History and evolution − source: -
Name, Scope and Binding (2) in Text: Chapter 5
Name, Scope and Binding (2) In Text: Chapter 5 N. Meng, F. Poursardar Variable • A program variable is an abstraction of a memory cell or a collection of cells • It has several attributes – Name: A mnemonic character string – Address – Type 2 Variable Attributes (continued) • Storage Bindings – Allocation o Getting a memory cell from a pool of available memory to bind to a variable – Deallocation o Putting a memory cell that has been unbound from a variable back into the pool • Lifetime – The lifetime of a variable is the time during which it is bound to a particular memory cell 3 Object Lifetime and Storage Management • Key events: creation of objects, creation of bindings, references to variables (which use bindings), (temporary) deactivation of bindings, reactivation of bindings, destruction of bindings, and destruction of objects. • Binding lifetime: the period of time from creation to destruction of a name-to-object binding. • Object lifetime: the time between the creation and destruction of an objects is the object’s lifetime: – If object outlives binding it's garbage. – If binding outlives object it's a dangling reference. • Scope: the textual region of the program in which the binding is active; we sometimes use the word scope as a noun all by itself, without an indirect object. Lifetime • If an object’s memory binding outlives its access binding, we get garbage • If an object’s access binding outlives its memory binding, we get a dangling reference • Variable lifetime begins at allocation, and ends at deallocation either by the program or garbage collector 5 Categories of Variables by Lifetimes • Static • Stack-dynamic • Explicit heap-dynamic • Implicit heap-dynamic Storage Allocation Mechanisms • Static: objects are given an absolute address that is retained throughout the program’s execution. -
Memory Management Programming Guide
Memory Management Programming Guide Performance 2010-06-24 PROVIDED “AS IS,” AND YOU, THE READER, ARE ASSUMING THE ENTIRE RISK AS TO ITS QUALITY Apple Inc. AND ACCURACY. © 2010 Apple Inc. IN NO EVENT WILL APPLE BE LIABLE FOR DIRECT, All rights reserved. INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES RESULTING FROM ANY DEFECT OR INACCURACY IN THIS DOCUMENT, even No part of this publication may be reproduced, if advised of the possibility of such damages. stored in a retrieval system, or transmitted, in THE WARRANTY AND REMEDIES SET FORTH ABOVE any form or by any means, mechanical, ARE EXCLUSIVE AND IN LIEU OF ALL OTHERS, ORAL OR WRITTEN, EXPRESS OR IMPLIED. No Apple electronic, photocopying, recording, or dealer, agent, or employee is authorized to make otherwise, without prior written permission of any modification, extension, or addition to this Apple Inc., with the following exceptions: Any warranty. person is hereby authorized to store Some states do not allow the exclusion or limitation of implied warranties or liability for incidental or documentation on a single computer for consequential damages, so the above limitation or personal use only and to print copies of exclusion may not apply to you. This warranty gives you specific legal rights, and you may also have documentation for personal use provided that other rights which vary from state to state. the documentation contains Apple’s copyright notice. The Apple logo is a trademark of Apple Inc. Use of the “keyboard” Apple logo (Option-Shift-K) for commercial purposes without the prior written consent of Apple may constitute trademark infringement and unfair competition in violation of federal and state laws. -
Contents Credits & Contacts
Overload issue 63 october 2004 contents credits & contacts Overload Editor: The Encapsulate Context Pattern Alan Griffiths Allan Kelly 6 [email protected] [email protected] Microsoft Visual C++ and Win32 Contributing Editor: Structured Exception Handling Mark Radford [email protected] Roger Orr 15 A Mini-project to Decode a Advisors: Mini-language Thomas Guest 20 Phil Bass [email protected] Garbage Collection and Object Lifetime Thaddaeus Frogley Ric Parkin 24 [email protected] Richard Blundell C++ Lookup Mysteries [email protected] Sven Rosvall 28 Advertising: Chris Lowe [email protected] Overload is a publication of the ACCU. For details of the ACCU and other ACCU publications and activities, see the ACCU website. ACCU Website: http://www.accu.org/ Information and Membership: Join on the website or contact David Hodge [email protected] Publications Officer: John Merrells [email protected] ACCU Chair: Ewan Milne [email protected] 3 Overload issue 63 october 2004 Editorial: The Buzzword Adoption Pattern? n my last editorial (in Overload 60, called “An Industry That Refuses to Learn”) I asserted that the software development industry has not made significant progress Iin the last quarter of a century. This assertion provoked enough of a response to fill the letters page in the following issue. I’m pleased about that, but at the same time, not so pleased. I’m pleased because I managed to provoke people into putting pen to paper – or rather, in this day and age, putting fingers to keyboard. I’m not so pleased because the response was one of overwhelming agreement, which is unfortunate because it suggests that any hopes I may have had that my experience is the odd one out, are false.