Lecture 9: Programming Languages: Semantics
Total Page:16
File Type:pdf, Size:1020Kb
Load more
Recommended publications
-
SJC – Small Java Compiler
SJC – Small Java Compiler User Manual Stefan Frenz Translation: Jonathan Brase original version: 2011/06/08 latest document update: 2011/08/24 Compiler Version: 182 Java is a registered trademark of Oracle/Sun Table of Contents 1 Quick introduction.............................................................................................................................4 1.1 Windows...........................................................................................................................................4 1.2 Linux.................................................................................................................................................5 1.3 JVM Environment.............................................................................................................................5 1.4 QEmu................................................................................................................................................5 2 Hello World.......................................................................................................................................6 2.1 Source Code......................................................................................................................................6 2.2 Compilation and Emulation...............................................................................................................8 2.3 Details...............................................................................................................................................9 -
Java (Programming Langua a (Programming Language)
Java (programming language) From Wikipedia, the free encyclopedialopedia "Java language" redirects here. For the natural language from the Indonesian island of Java, see Javanese language. Not to be confused with JavaScript. Java multi-paradigm: object-oriented, structured, imperative, Paradigm(s) functional, generic, reflective, concurrent James Gosling and Designed by Sun Microsystems Developer Oracle Corporation Appeared in 1995[1] Java Standard Edition 8 Update Stable release 5 (1.8.0_5) / April 15, 2014; 2 months ago Static, strong, safe, nominative, Typing discipline manifest Major OpenJDK, many others implementations Dialects Generic Java, Pizza Ada 83, C++, C#,[2] Eiffel,[3] Generic Java, Mesa,[4] Modula- Influenced by 3,[5] Oberon,[6] Objective-C,[7] UCSD Pascal,[8][9] Smalltalk Ada 2005, BeanShell, C#, Clojure, D, ECMAScript, Influenced Groovy, J#, JavaScript, Kotlin, PHP, Python, Scala, Seed7, Vala Implementation C and C++ language OS Cross-platform (multi-platform) GNU General Public License, License Java CommuniCommunity Process Filename .java , .class, .jar extension(s) Website For Java Developers Java Programming at Wikibooks Java is a computer programming language that is concurrent, class-based, object-oriented, and specifically designed to have as few impimplementation dependencies as possible.ble. It is intended to let application developers "write once, run ananywhere" (WORA), meaning that code that runs on one platform does not need to be recompiled to rurun on another. Java applications ns are typically compiled to bytecode (class file) that can run on anany Java virtual machine (JVM)) regardless of computer architecture. Java is, as of 2014, one of tthe most popular programming ng languages in use, particularly for client-server web applications, witwith a reported 9 million developers.[10][11] Java was originallyy developed by James Gosling at Sun Microsystems (which has since merged into Oracle Corporation) and released in 1995 as a core component of Sun Microsystems'Micros Java platform. -
The Java® Language Specification Java SE 8 Edition
The Java® Language Specification Java SE 8 Edition James Gosling Bill Joy Guy Steele Gilad Bracha Alex Buckley 2015-02-13 Specification: JSR-337 Java® SE 8 Release Contents ("Specification") Version: 8 Status: Maintenance Release Release: March 2015 Copyright © 1997, 2015, Oracle America, Inc. and/or its affiliates. 500 Oracle Parkway, Redwood City, California 94065, U.S.A. All rights reserved. Oracle and Java are registered trademarks of Oracle and/or its affiliates. Other names may be trademarks of their respective owners. The Specification provided herein is provided to you only under the Limited License Grant included herein as Appendix A. Please see Appendix A, Limited License Grant. To Maurizio, with deepest thanks. Table of Contents Preface to the Java SE 8 Edition xix 1 Introduction 1 1.1 Organization of the Specification 2 1.2 Example Programs 6 1.3 Notation 6 1.4 Relationship to Predefined Classes and Interfaces 7 1.5 Feedback 7 1.6 References 7 2 Grammars 9 2.1 Context-Free Grammars 9 2.2 The Lexical Grammar 9 2.3 The Syntactic Grammar 10 2.4 Grammar Notation 10 3 Lexical Structure 15 3.1 Unicode 15 3.2 Lexical Translations 16 3.3 Unicode Escapes 17 3.4 Line Terminators 19 3.5 Input Elements and Tokens 19 3.6 White Space 20 3.7 Comments 21 3.8 Identifiers 22 3.9 Keywords 24 3.10 Literals 24 3.10.1 Integer Literals 25 3.10.2 Floating-Point Literals 31 3.10.3 Boolean Literals 34 3.10.4 Character Literals 34 3.10.5 String Literals 35 3.10.6 Escape Sequences for Character and String Literals 37 3.10.7 The Null Literal 38 3.11 Separators -
Building Useful Program Analysis Tools Using an Extensible Java Compiler
Building Useful Program Analysis Tools Using an Extensible Java Compiler Edward Aftandilian, Raluca Sauciuc Siddharth Priya, Sundaresan Krishnan Google, Inc. Google, Inc. Mountain View, CA, USA Hyderabad, India feaftan, [email protected] fsiddharth, [email protected] Abstract—Large software companies need customized tools a specific task, but they fail for several reasons. First, ad- to manage their source code. These tools are often built in hoc program analysis tools are often brittle and break on an ad-hoc fashion, using brittle technologies such as regular uncommon-but-valid code patterns. Second, simple ad-hoc expressions and home-grown parsers. Changes in the language cause the tools to break. More importantly, these ad-hoc tools tools don’t provide sufficient information to perform many often do not support uncommon-but-valid code code patterns. non-trivial analyses, including refactorings. Type and symbol We report our experiences building source-code analysis information is especially useful, but amounts to writing a tools at Google on top of a third-party, open-source, extensible type-checker. Finally, more sophisticated program analysis compiler. We describe three tools in use on our Java codebase. tools are expensive to create and maintain, especially as the The first, Strict Java Dependencies, enforces our dependency target language evolves. policy in order to reduce JAR file sizes and testing load. The second, error-prone, adds new error checks to the compilation In this paper, we present our experience building special- process and automates repair of those errors at a whole- purpose tools on top of the the piece of software in our codebase scale. -
A Guide to Dynamic Semantics
A Guide to Dynamic Semantics Paul Dekker ILLC/Department of Philosophy University of Amsterdam September 15, 2008 1 Introduction In this article we give an introduction to the idea and workings of dynamic se- mantics. We start with an overview of its historical background and motivation in this introductory section. An in-depth description of a paradigm version of dynamic semantics, Dynamic Predicate Logic, is given in section 2. In section 3 we discuss some applications of the dynamic kind of interpretation to illustrate how it can be taken to neatly account for a vast number of empirical phenom- ena. In section 4 more radical extensions of the basic paradigm are discussed, all of them systematically incorporating previously deemed pragmatic aspects of meaning in the interpretational system. Finally, a discussion of some more general, philosophical and theoretical, issues surrounding dynamic semantics can be found in section 5. 1.1 Theoretical Background What is dynamic semantics. Some people claim it embodies a radical new view of meaning, departing from the main logical paradigm as it has been prominent in most of the previous century. Meaning, or so it is said, is not some object, or some Platonic entity, but it is something that changes information states. A very simple-minded way of putting the idea is that people uses languages, they have cognitive states, and what language does is change these states. “Natu- ral languages are programming languages for minds”, it has been said. Others build on the assumption that natural language and its interpretation is not just concerned with describing an independently given world, but that there are lots of others things relevant in the interpretation of discourse, and lots of other functions of language than a merely descriptive one. -
Chapter 3 Describing Syntax and Semantics
Chapter 3 Describing Syntax and Semantics 3.1 Introduction 110 3.2 The General Problem of Describing Syntax 111 3.3 Formal Methods of Describing Syntax 113 3.4 Attribute Grammars 128 3.5 Describing the Meanings of Programs: Dynamic Semantics 134 Summary • Bibliographic Notes • Review Questions • Problem Set 155 CMPS401 Class Notes (Chap03) Page 1 / 25 Dr. Kuo-pao Yang Chapter 3 Describing Syntax and Semantics 3.1 Introduction 110 Syntax – the form of the expressions, statements, and program units Semantics - the meaning of the expressions, statements, and program units. Ex: the syntax of a Java while statement is while (boolean_expr) statement – The semantics of this statement form is that when the current value of the Boolean expression is true, the embedded statement is executed. – The form of a statement should strongly suggest what the statement is meant to accomplish. 3.2 The General Problem of Describing Syntax 111 A sentence or “statement” is a string of characters over some alphabet. The syntax rules of a language specify which strings of characters from the language’s alphabet are in the language. A language is a set of sentences. A lexeme is the lowest level syntactic unit of a language. It includes identifiers, literals, operators, and special word (e.g. *, sum, begin). A program is strings of lexemes. A token is a category of lexemes (e.g., identifier). An identifier is a token that have lexemes, or instances, such as sum and total. Ex: index = 2 * count + 17; Lexemes Tokens index identifier = equal_sign 2 int_literal * mult_op count identifier + plus_op 17 int_literal ; semicolon CMPS401 Class Notes (Chap03) Page 2 / 25 Dr. -
SUBJECT-COMPUTER CLASS-12 CHAPTER 9 – Compiling and Running Java Programs
SUBJECT-COMPUTER CLASS-12 CHAPTER 9 – Compiling and Running Java Programs Introduction to Java programming JAVA was developed by Sun Microsystems Inc in 1991, later acquired by Oracle Corporation. It was developed by James Gosling and Patrick Naughton. It is a simple programming language. Writing, compiling and debugging a program is easy in java. It helps to create modular programs and reusable code. Bytecode javac compiler of JDK compiles the java source code into bytecode so that it can be executed by JVM. The bytecode is saved in a .class file by compiler. Java Virtual Machine (JVM) This is generally referred as JVM. Before, we discuss about JVM lets see the phases of program execution. Phases are as follows: we write the program, then we compile the program and at last we run the program. 1) Writing of the program is of course done by java programmer. 2) Compilation of program is done by javac compiler, javac is the primary java compiler included in java development kit (JDK). It takes java program as input and generates java bytecode as output. 3) In third phase, JVM executes the bytecode generated by compiler. This is called program run phase. So, now that we understood that the primary function of JVM is to execute the bytecode produced by compiler. Characteristics of Java Simple Java is very easy to learn, and its syntax is simple, clean and easy to understand. Multi-threaded Multithreading capabilities come built right into the Java language. This means it is possible to build highly interactive and responsive apps with a number of concurrent threads of activity. -
Coqjvm: an Executable Specification of the Java Virtual Machine Using
CoqJVM: An Executable Specification of the Java Virtual Machine using Dependent Types Robert Atkey LFCS, School of Informatics, University of Edinburgh Mayfield Rd, Edinburgh EH9 3JZ, UK [email protected] Abstract. We describe an executable specification of the Java Virtual Machine (JVM) within the Coq proof assistant. The principal features of the development are that it is executable, meaning that it can be tested against a real JVM to gain confidence in the correctness of the specification; and that it has been written with heavy use of dependent types, this is both to structure the model in a useful way, and to constrain the model to prevent spurious partiality. We describe the structure of the formalisation and the way in which we have used dependent types. 1 Introduction Large scale formalisations of programming languages and systems in mechanised theorem provers have recently become popular [4–6, 9]. In this paper, we describe a formalisation of the Java virtual machine (JVM) [8] in the Coq proof assistant [11]. The principal features of this formalisation are that it is executable, meaning that a purely functional JVM can be extracted from the Coq development and – with some O’Caml glue code – executed on real Java bytecode output from the Java compiler; and that it is structured using dependent types. The motivation for this development is to act as a basis for certified consumer- side Proof-Carrying Code (PCC) [12]. We aim to prove the soundness of program logics and correctness of proof checkers against the model, and extract the proof checkers to produce certified stand-alone tools. -
Chapter 9: Java
,ch09.6595 Page 159 Friday, March 25, 2005 2:47 PM Chapter 9 CHAPTER 9 Java Many Java developers like Integrated Development Environments (IDEs) such as Eclipse. Given such well-known alternatives as Java IDEs and Ant, readers could well ask why they should even think of using make on Java projects. This chapter explores the value of make in these situations; in particular, it presents a generalized makefile that can be dropped into just about any Java project with minimal modification and carry out all the standard rebuilding tasks. Using make with Java raises several issues and introduces some opportunities. This is primarily due to three factors: the Java compiler, javac, is extremely fast; the stan- dard Java compiler supports the @filename syntax for reading “command-line param- eters” from a file; and if a Java package is specified, the Java language specifies a path to the .class file. Standard Java compilers are very fast. This is primarily due to the way the import directive works. Similar to a #include in C, this directive is used to allow access to externally defined symbols. However, rather than rereading source code, which then needs to be reparsed and analyzed, Java reads the class files directly. Because the symbols in a class file cannot change during the compilation process, the class files are cached by the compiler. In even medium-sized projects, this means the Java com- piler can avoid rereading, parsing, and analyzing literally millions of lines of code compared with C. A more modest performance improvement is due to the bare mini- mum of optimization performed by most Java compilers. -
A Dynamic Semantics of Single-Wh and Multiple-Wh Questions*
Proceedings of SALT 30: 376–395, 2020 A dynamic semantics of single-wh and multiple-wh questions* Jakub Dotlacilˇ Floris Roelofsen Utrecht University University of Amsterdam Abstract We develop a uniform analysis of single-wh and multiple-wh questions couched in dynamic inquisitive semantics. The analysis captures the effects of number marking on which-phrases, and derives both mention-some and mention-all readings as well as an often neglected partial mention- some reading in multiple-wh questions. Keywords: question semantics, multiple-wh questions, mention-some, dynamic inquisitive semantics. 1 Introduction The goal of this paper is to develop an analysis of single-wh and multiple-wh questions in English satisfying the following desiderata: a) Uniformity. The interpretation of single-wh and multiple-wh questions is derived uniformly. The same mechanisms are operative in both types of questions. b) Mention-some vs mention-all. Mention-some and mention-all readings are derived in a principled way, including ‘partial mention-some readings’ in multiple-wh questions (mention-all w.r.t. one of the wh-phrases but mention-some w.r.t. the other wh-phrase). c) Number marking. The effects of number marking on wh-phrases are captured. In particular, singular which-phrases induce a uniqueness requirement in single-wh questions but do not block pair-list readings in multiple-wh questions. To our knowledge, no existing account fully satisfies these desiderata. While we cannot do justice to the rich literature on the topic, let us briefly mention a number of prominent proposals. Groenendijk & Stokhof(1984) provide a uniform account of single-wh and multiple-wh ques- tions, but their proposal does not successfully capture mention-some readings and the effects of number marking. -
Free Choice and Homogeneity
Semantics & Pragmatics Volume 12, Article 23, 2019 https://doi.org/10.3765/sp.12.23 This is an early access version of Goldstein, Simon. 2019. Free choice and homogeneity. Semantics and Prag- matics 12(23). 1–47. https://doi.org/10.3765/sp.12.23. This version will be replaced with the final typeset version in due course. Note that page numbers will change, so cite with caution. ©2019 Simon Goldstein This is an open-access article distributed under the terms of a Creative Commons Attribution License (https://creativecommons.org/licenses/by/3.0/). early access Free choice and homogeneity* Simon Goldstein Australian Catholic University Abstract This paper develops a semantic solution to the puzzle of Free Choice permission. The paper begins with a battery of impossibility results showing that Free Choice is in tension with a variety of classical principles, including Disjunction Introduction and the Law of Excluded Middle. Most interestingly, Free Choice appears incompatible with a principle concerning the behavior of Free Choice under negation, Double Prohibition, which says that Mary can’t have soup or salad implies Mary can’t have soup and Mary can’t have salad. Alonso-Ovalle 2006 and others have appealed to Double Prohibition to motivate pragmatic accounts of Free Choice. Aher 2012, Aloni 2018, and others have developed semantic accounts of Free Choice that also explain Double Prohibition. This paper offers a new semantic analysis of Free Choice designed to handle the full range of impossibility results involved in Free Choice. The paper develops the hypothesis that Free Choice is a homogeneity effect. -
Chapter 3 – Describing Syntax and Semantics CS-4337 Organization of Programming Languages
!" # Chapter 3 – Describing Syntax and Semantics CS-4337 Organization of Programming Languages Dr. Chris Irwin Davis Email: [email protected] Phone: (972) 883-3574 Office: ECSS 4.705 Chapter 3 Topics • Introduction • The General Problem of Describing Syntax • Formal Methods of Describing Syntax • Attribute Grammars • Describing the Meanings of Programs: Dynamic Semantics 1-2 Introduction •Syntax: the form or structure of the expressions, statements, and program units •Semantics: the meaning of the expressions, statements, and program units •Syntax and semantics provide a language’s definition – Users of a language definition •Other language designers •Implementers •Programmers (the users of the language) 1-3 The General Problem of Describing Syntax: Terminology •A sentence is a string of characters over some alphabet •A language is a set of sentences •A lexeme is the lowest level syntactic unit of a language (e.g., *, sum, begin) •A token is a category of lexemes (e.g., identifier) 1-4 Example: Lexemes and Tokens index = 2 * count + 17 Lexemes Tokens index identifier = equal_sign 2 int_literal * mult_op count identifier + plus_op 17 int_literal ; semicolon Formal Definition of Languages • Recognizers – A recognition device reads input strings over the alphabet of the language and decides whether the input strings belong to the language – Example: syntax analysis part of a compiler - Detailed discussion of syntax analysis appears in Chapter 4 • Generators – A device that generates sentences of a language – One can determine if the syntax of a particular sentence is syntactically correct by comparing it to the structure of the generator 1-5 Formal Methods of Describing Syntax •Formal language-generation mechanisms, usually called grammars, are commonly used to describe the syntax of programming languages.