A Declarative Extension of Parsing Expression Grammars for Recognizing Most Programming Languages
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Beginning Portable Shell Scripting from Novice to Professional
Beginning Portable Shell Scripting From Novice to Professional Peter Seebach 10436fmfinal 1 10/23/08 10:40:24 PM Beginning Portable Shell Scripting: From Novice to Professional Copyright © 2008 by Peter Seebach All rights reserved. No part of this work may be reproduced or transmitted in any form or by any means, electronic or mechanical, including photocopying, recording, or by any information storage or retrieval system, without the prior written permission of the copyright owner and the publisher. ISBN-13 (pbk): 978-1-4302-1043-6 ISBN-10 (pbk): 1-4302-1043-5 ISBN-13 (electronic): 978-1-4302-1044-3 ISBN-10 (electronic): 1-4302-1044-3 Printed and bound in the United States of America 9 8 7 6 5 4 3 2 1 Trademarked names may appear in this book. Rather than use a trademark symbol with every occurrence of a trademarked name, we use the names only in an editorial fashion and to the benefit of the trademark owner, with no intention of infringement of the trademark. Lead Editor: Frank Pohlmann Technical Reviewer: Gary V. Vaughan Editorial Board: Clay Andres, Steve Anglin, Ewan Buckingham, Tony Campbell, Gary Cornell, Jonathan Gennick, Michelle Lowman, Matthew Moodie, Jeffrey Pepper, Frank Pohlmann, Ben Renow-Clarke, Dominic Shakeshaft, Matt Wade, Tom Welsh Project Manager: Richard Dal Porto Copy Editor: Kim Benbow Associate Production Director: Kari Brooks-Copony Production Editor: Katie Stence Compositor: Linda Weidemann, Wolf Creek Press Proofreader: Dan Shaw Indexer: Broccoli Information Management Cover Designer: Kurt Krames Manufacturing Director: Tom Debolski Distributed to the book trade worldwide by Springer-Verlag New York, Inc., 233 Spring Street, 6th Floor, New York, NY 10013. -
On the Relation Between Context-Free Grammars And
On the Relation between Context-Free Grammars and Parsing Expression Grammars Fabio Mascarenhas Department of Computer Science – UFRJ – Rio de Janeiro – Brazil S´ergio Medeiros School of Science and Technology – UFRN – Natal – Brazil Roberto Ierusalimschy Department of Computer Science – PUC-Rio – Rio de Janeiro – Brazil Abstract Context-Free Grammars (CFGs) and Parsing Expression Grammars (PEGs) have several similarities and a few differences in both their syntax and seman- tics, but they are usually presented through formalisms that hinder a proper comparison. In this paper we present a new formalism for CFGs that highlights the similarities and differences between them. The new formalism borrows from PEGs the use of parsing expressions and the recognition-based semantics. We show how one way of removing non-determinism from this formalism yields a formalism with the semantics of PEGs. We also prove, based on these new formalisms, how LL(1) grammars define the same language whether interpreted as CFGs or as PEGs, and also show how strong-LL(k), right-linear, and LL- regular grammars have simple language-preserving translations from CFGs to PEGs. Once these classes of CFGs can be automatically translated to equivalent PEGs, we can reuse classic top-down grammars in PEG-based tools. Keywords: Context-free grammars, parsing expression grammars, parsing, LL(1), LL(k), LL-regular, right-linear grammars, natural semantics arXiv:1304.3177v2 [cs.FL] 13 Feb 2014 1. Introduction Context-Free Grammars (CFGs) are the formalism of choice for describing the syntax of programming languages. A CFG describes a language as the set Email addresses: [email protected] (Fabio Mascarenhas), [email protected] (S´ergio Medeiros), [email protected] (Roberto Ierusalimschy) Preprint submitted to Science of Computer Programming March 19, 2018 of strings generated from the grammar’s initial symbol by a sequence of rewrit- ing steps. -
Parsing Expression Grammars: a Recognition-Based Syntactic Foundation
Parsing Expression Grammars: A Recognition-Based Syntactic Foundation Bryan Ford Massachusetts Institute of Technology Cambridge, MA [email protected] Abstract 1 Introduction For decades we have been using Chomsky’s generative system of Most language syntax theory and practice is based on generative grammars, particularly context-free grammars (CFGs) and regu- systems, such as regular expressions and context-free grammars, in lar expressions (REs), to express the syntax of programming lan- which a language is defined formally by a set of rules applied re- guages and protocols. The power of generative grammars to ex- cursively to generate strings of the language. A recognition-based press ambiguity is crucial to their original purpose of modelling system, in contrast, defines a language in terms of rules or predi- natural languages, but this very power makes it unnecessarily diffi- cates that decide whether or not a given string is in the language. cult both to express and to parse machine-oriented languages using Simple languages can be expressed easily in either paradigm. For CFGs. Parsing Expression Grammars (PEGs) provide an alterna- example, fs 2 a∗ j s = (aa)ng is a generative definition of a trivial tive, recognition-based formal foundation for describing machine- language over a unary character set, whose strings are “constructed” oriented syntax, which solves the ambiguity problem by not intro- by concatenating pairs of a’s. In contrast, fs 2 a∗ j (jsj mod 2 = 0)g ducing ambiguity in the first place. Where CFGs express nondeter- is a recognition-based definition of the same language, in which a ministic choice between alternatives, PEGs instead use prioritized string of a’s is “accepted” if its length is even. -
Php Tutorial
PHP About the Tutorial The PHP Hypertext Preprocessor (PHP) is a programming language that allows web developers to create dynamic content that interacts with databases. PHP is basically used for developing web-based software applications. This tutorial will help you understand the basics of PHP and how to put it in practice. Audience This tutorial has been designed to meet the requirements of all those readers who are keen to learn the basics of PHP. Prerequisites Before proceeding with this tutorial, you should have a basic understanding of computer programming, Internet, Database, and MySQL. Copyright & Disclaimer © Copyright 2016 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 is prohibited to reuse, retain, copy, distribute or republish any contents or a part of contents of this e-book in any manner 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] i PHP Table of Contents About the Tutorial ........................................................................................................................................... -
Bash Guide for Beginners
Bash Guide for Beginners Machtelt Garrels Garrels BVBA <tille wants no spam _at_ garrels dot be> Version 1.11 Last updated 20081227 Edition Bash Guide for Beginners Table of Contents Introduction.........................................................................................................................................................1 1. Why this guide?...................................................................................................................................1 2. Who should read this book?.................................................................................................................1 3. New versions, translations and availability.........................................................................................2 4. Revision History..................................................................................................................................2 5. Contributions.......................................................................................................................................3 6. Feedback..............................................................................................................................................3 7. Copyright information.........................................................................................................................3 8. What do you need?...............................................................................................................................4 9. Conventions used in this -
A Common Framework for Scripting Tutorials Erik Hjelmås and Ivar
A Common Framework for Scripting Tutorials Erik Hjelmås and Ivar Farup Abstract A scripting tutorial should focus on teaching the characteristics of scripting languages, avoiding the pitfall of teaching only syntax conversion from system programming languages. Examples should be selected to emphasize features of scripting languages in general (e.g. weak typing, associate arrays, “gluing”) and the scripting language at hand. Students might benefit from using the same framework (structure of programming elements and examples) for learning multiple scripting languages. Their existing programming skills should be reused while newly introduced scripting concepts should be reinforced in subsequent examples. 1 Introduction Scripting languages are popular for solving problems in many different domains [8]. Some are general scripting languages such as Perl, Python and Ruby, while others are slightly domain-specific (platform-specific: Bash, PowerShell) or very domain-specific (application-specific: Cfengine, Matlab). They can be characterized as high-level and weakly typed, as opposed to system programming languages such as Java and C++ [11]. In higher education, scripting languages are used both for introductory programming courses [14] and for lab exercises in later courses. It is in this last context the present work seeks to contribute to a better learning experience for students. Although much effort has been invested in researching ways of teaching introductory programming [12], the problem of how to convert existing programming skills to a new language seems slightly overlooked. The way this is solved in practice is by either providing a short tutorial style introduction to the new language, or referring the student to an online tutorial resource. -
Korn Shell Variables
V4.1 cover Front cover Korn and Bash Shell Programming (Course code AL32) Student Notebook ERC 1.0 IBM Certified Course Material Student Notebook Trademarks IBM® is a registered trademark of International Business Machines Corporation. The following are trademarks of International Business Machines Corporation in the United States, or other countries, or both: AIX® AIX 5L™ Language Environment® OS/2® POWER™ RISC System/6000® RS/6000® Java and all Java-based trademarks are trademarks of Sun Microsystems, Inc. in the United States, other countries, or both. Windows is a trademark of Microsoft Corporation in the United States, other countries, or both. UNIX® is a registered trademark of The Open Group in the United States and other countries. Linux® is a registered trademark of Linus Torvalds in the United States, other countries, or both. Other company, product, or service names may be trademarks or service marks of others. October 2007 edition The information contained in this document has not been submitted to any formal IBM test and is distributed on an “as is” basis without any warranty either express or implied. The use of this information or the implementation of any of these techniques is a customer responsibility and depends on the customer’s ability to evaluate and integrate them into the customer’s operational environment. While each item may have been reviewed by IBM for accuracy in a specific situation, there is no guarantee that the same or similar results will result elsewhere. Customers attempting to adapt these techniques to their own environments do so at their own risk. © Copyright International Business Machines Corporation 2007. -
A Programming Language Where the Syntax and Semantics Are Mutable at Runtime
DEPARTMENT OF COMPUTER SCIENCE A Programming Language Where the Syntax and Semantics Are Mutable at Runtime Christopher Graham Seaton A dissertation submitted to the University of Bristol in accordance with the requirements of the degree of Master of Enginnering in the Faculty of Engineering May 2007 CSMENG-07 Declaration A dissertation submitted to the University of Bristol in accordance with the requirements of the degree of Master of Enginnering in the Faculty of Engineering. It has not been submitted for any other degree or diploma of any examining body. Except where specifically acknowledged, it is all the work of the Author. Christopher Graham Seaton, May 2007 SUMMARY Katahdin is a programming language where the syntax and semantics are mu- table at runtime. The Katahdin interpreter parses and executes programs ac- cording to a language definition that can be modified by the running program. Commands to modify the language definition are similar to those that define new types and functions in other languages, and can be collected into lan- guage definition modules. Katahdin can execute programs written in any language which it has a defini- tion module for. The definition of more than one language can be composed allowing more than one language to be used in the same program, the same file, and even the same function. Data and code is shared between all lan- guages, with a function defined in one language callable from another with no binding layer. Traditional language development involves using a parser generator tool to generate a static parser from the language grammar. Katahdin’s approach is to just-in-time compile a parser from the grammar as the program runs. -
Rc the Plan 9 Shell
Rc ߞ The Plan 9 Shell Tom Duff [email protected]−labs.com ABSTRACT Rc is a command interpreter for Plan 9 that provides similar facilities to UNIXߣs Bourne shell, with some small additions and less idiosyncratic syntax. This paper uses numerous examples to describe rcߣs features, and contrasts rc with the Bourne shell, a model that many readers will be familiar with. 1. Introduction Rc is similar in spirit but different in detail from UNIXߣs Bourne shell. This paper describes rcߣs principal features with many small examples and a few larger ones. It assumes familiarity with the Bourne shell. 2. Simple commands For the simplest uses rc has syntax familiar to Bourne-shell users. All of the fol lowing behave as expected: date cat /lib/news/build who >user.names who >>user.names wc <file echo [a−f]*.c who | wc who; date vc *.c & mk && v.out /*/bin/fb/* rm −r junk || echo rm failed! 3. Quotation An argument that contains a space or one of rcߣs other syntax characters must be enclosed in apostrophes (’): rm ’odd file name’ An apostrophe in a quoted argument must be doubled: echo ’How’’s your father?’ 4. Patterns An unquoted argument that contains any of the characters *?[is a pattern to be matched against file names. A * character matches any sequence of characters, ? matches any single character, and [class] matches any character in the class, unless the first character of class is ~, in which case the class is complemented. The class may 2 also contain pairs of characters separated by −, standing for all characters lexically between the two. -
Introduction to Bash Programming
Bash Scripting: Advanced Topics CISC3130, Spring 2013 Dr. Zhang 1 Outline Review HW1, HW2 and Quiz2 Review of standard input/output/error How to redirect them ? Pipeline Review of bash scripting Functions Here documents Arrays 2 Homework 2 match phone numbers in text file 7188174484, 718-817-4484, (718)817,4484 817-4484, or 817,4484, 8174484. (01)718,817,4484, 01,718-817-4484 grep -f phone.grep file.txt , where phone.grep: [^0-9][0-9]\{10\}$ Match 10 digits at end of line [^0-9][0-9]\{10\}[^0-9] Match 10 digits, and a non-digit char [^0-9][0-9]\{3\}\-[0-9]\{3\}\-[0-9]\{4\}$ 718-817,4484 at end of line [^0-9][0-9]\{3\}\-[0-9]\{3\}\-[0-9]\{4\}[^0-9] [^0-9][0-9]\{3\}\,[0-9]\{4\}$ [^0-9][0-9]\{3\}\,[0-9]\{4\}[^0-9] [^0-9][0-9]\{3\}\-[0-9]\{4\}$ [^0-9][0-9]\{3\}\-[0-9]\{4\}[^0-9] 3 Homework 2 [^0-9]*\([0-9]\{2\}\)\([0-9]\{3\}\)[0-9]\{3\}\,[0-9]\{4\}$ [^0-9]*\([0-9]\{2\}\)\([0-9]\{3\}\)[0-9]\{3\}\,[0-9]\{4\}[^0-9] [^0-9]*\([0-9]\{2\}\)\([0-9]\{3\}\))?[0-9]\{3\}\-[0-9]\{4\}$ [^0-9]*\([0-9]\{2\}\)\([0-9]\{3\}\))?[0-9]\{3\}\-[0-9]\{4\}[^0-9] [^0-9]*[0-9]\{2\}\,[0-9]\{3\}\,[0-9]\{3\}\,[0-9]\{4\}$ [^0-9]*[0-9]\{2\}\,[0-9]\{3\}\-[0-9]\{3\}\-[0-9]\{4\}[^0-9] [^0-9]*[0-9]\{2\}\,[0-9]\{3\}\-[0-9]\{3\}\-[0-9]\{4\}$ [^0-9]*[0-9]\{2\}\,[0-9]\{3\}\,[0-9]\{3\}\,[0-9]\{4\}[^0-9] 4 Homework 2 Write a sed script file that remove all one-line comments from C/C++ source code files. -
Tutorials Point, Simply Easy Learning PHP BASIC
PHP TutorialsBASIC Point, Simply Easy Learning PHP started out as a small open source project that evolved as more and more people found out how useful it was. Rasmus Lerdorf unleashed the first version of PHP way back in 1994. PHP is a recursive acronym for "PHP: Hypertext Preprocessor". PHP is a server side scripting language that is embedded in HTML. It is used to manage dynamic content, databases, session tracking, even build entire e-commerce sites. It is integrated with a number of popular databases, including MySQL, PostgreSQL, Oracle, Sybase, Informix, and Microsoft SQL Server. PHP is pleasingly zippy in its execution, especially when compiled as an Apache module on the Unix side. The MySQL server, once started, executes even very complex queries with huge result sets in record-setting time. PHP supports a large number of major protocols such as POP3, IMAP, and LDAP. PHP4 added support for Java and distributed object architectures (COM and CORBA), making n-tier development a possibility for the first time. PHP is forgiving: PHP language tries to be as forgiving as possible. PHP Syntax is C-Like. Common uses of PHP: PHP performs system functions, i.e. from files on a system it can create, open, read, write, and close them. PHP can handle forms, i.e. gather data from files, save data to a file, thru email you can send data, return data to the user. You add, delete, modify elements within your database thru PHP. Access cookies variables and set cookies. Using PHP, you can restrict users to access some pages of your website. -
Declare Multiline String in Python
Declare Multiline String In Python Narrowing and idiographic Paul top-up some gadwalls so improbably! Unsensibly extrapolated, Tibold stridulated whiteness and ghettoizes enchondroma. Paragraphic and sensitive Lloyd always italicizes see and manicure his fusser. Make it in python? Java 13 why text blocks are worth its wait JAXenter. Return value through your offer other escape sequences in libraries to declare multiline string in python question about controlling and every time looking for? Output Multiline Strings in GitHub Actions Single or output Multiline output failed attempt Option 1 string substitution Option 2 environment variable. CoffeeScript borrows the color-quoted string syntax from Python. Multi-line String literals Stephen Colebourne's blog Java 7. String literal Wikipedia. How python multiline strings in suite scope of declaration itself? Python Strings Python Education Google Developers. Unlike Python raw-strings C style raw strings can contain multi-line text area even binary. If account are coming back Go away another language like Ruby or Python there altogether a lot. Please enter multiline in python multi line! How python multiline raw variant with a part of declaration of. A string literal can tie multiple lines but all must crack a backslash at. Forbid writing classes. Most recommended way too many cases where spaces to multiline string in python? Calls this multiline string declared it. Forward three characters in python multiline string declared without the declaration of syntax highlighting. Python multiline string python code! Many different resource file with python can declare long string declared without direct object with proper number. How we assign a multi-line string strap a variable in Python Quora.