DOCSLIB.ORG

A Special-Purpose Language for Picture-Drawing

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
A Special-Purpose Language for Picture-Drawing The following paper was originally published in the Proceedings of the Conference on Domain-Specific Languages Santa Barbara, California, October 1997 A Special-Purpose Language for Picture-Drawing Samuel N. Kamin and David Hyatt University of Illinois, Urbana-Champaign For more information about USENIX Association contact: 1. Phone: 510 528-8649 2. FAX: 510 548-5738 3. Email: [email protected] 4. WWW URL:http://www.usenix.org A Sp ecial-Purp ose Language for Picture-Drawing y Samuel N. Kamin David Hyatt Computer Science Department University of Il linois at Urbana-Champaign Urbana, Il linois 61801 fs-kamin,[email protected] Abstract supp orted in programming languages. This supp ort means allowing the creation of \ rst-class" values of eachtyp e, that is, values not sub ject to arbitrary Special purpose languages are typical ly characterized restrictions based on the typ e. It also means pro- by a type of primitive data and domain-speci c oper- viding op erations appropriate to those typ es in a ations on this data. One approach to special purpose concise, non-bureaucratic form. language design is to embed the data and operations In our view, this approach to language design is p er- of the language within an existing functional lan- guage. The data can be de ned using the typecon- fectly suited to the design of sp ecial-purp ose lan- structions provided by the functional language, and guages. These languages are usually characterized the special purpose language then inherits al l of the byatyp e of primitive data sp eci c to a problem domain, and op erations on those data. These data features of the more general language. In this paper can b e incorp orated into a language having the typ e we outline a domain-speci c language, FPIC, for the representation of two-dimensional pictures. The constructions just mentioned. In fact, they can b e primitive data and operations are de ned in ML. We incorp orated into an existing functional language; outline the operations provided by the language, il- the typ e constructions will apply to the new data, lustrate the power of the language with examples, and the entire language will then b ecome a sp ecial- purp ose language, with its many other features in- and discuss the design process. cluded \for free." The principal weakness of many sp ecial-purp ose languages is that, b eyond a concise and natural 1 Intro duction syntax, and ecient implementation, for the val- ues and op erations sp eci c to the domain, over- FPIC is a sp ecial-purp ose language for drawing sim- arching language structure is weak. This weak- ple pictures. It was built by de ning typ es and ness would b e very signi cantly mitigated if sp ecial- functions in the functional language Standard ML purp ose languages were routinely designed|or at [6]. This metho d of construction is easy and results least prototyp ed|in the waywehave outlined. in a language with many useful features. In addi- This pap er is a case study of the design of FPIC ac- tion to b eing concise for small examples, FPIC is cording to this philosophy.We describ e the pro cess powerful enough to allow the programming of large by whichwe decided what the primitive data were programs and program libraries, an area in which and how they should b ehave, then describ e the lan- many sp ecial-purp ose languages are weak. guage itself with numerous examples. Our emphasis Functional programming has b een characterized throughout is on the advantages obtained byhaving in manyways. Our view is that it repre- the functional language sup erstructure of Standard sents an approach to language design. This ap- ML as part of FPIC. proach holds that some mathematical constructs| pro ducts, functions, disjoint unions, and others| are fundamental in computing and should b e well Partially supp orted by NSF Grant CCR 96{19655. y Current address: Netscap e Communications Corp., Mountain View, CA, hyatt@netscap e.com. 2 Simple FPIC Examples PIC [4] is a language for drawing simple pictures, such as trees and blo ck diagrams. It has primi- tives for drawing b oxes, circles, and other shap es, val nose = dtriangle; with or without lab els, and for drawing lines and circle 2.5 arrows b etween them. It also has a facility for nam- seq nose at 2.0,2.0 ing p oints on pictures, to b e used, for example, as seq nose rotate ~90.0 scale 0.7 at 1.2,2.7 the endp oints of lines and arrows. These constructs seq nose rotate 90.0 scale 0.7 at 3.1,2.7 seq doval scaleXY 0.5,0.3 at 1.7,0.7; are provided in a concise syntax, with a simple lan- guage structure including lo ops added on. The seq op eration simply places pictures on top of FPIC was inspired by PIC. Our goal was to demon- one another, without moving them either rightor strate that we could b ene t by following the lan- down. The expression pic at point draws the picture guage design philosophy outlined in the intro duc- pic with its reference p oint the lower-left corner at tion. That is, by using essentially the same primi- point. tive data typ es and op erations as in PIC, but em- An imp ortant feature of PIC, whichwehave b edding them in a functional language, we could obtain a far more p owerful language than PIC and adopted in FPIC, is the ability to name p oints in do so at a far lower cost than if we had built the a picture and subsequently refer to them. The com- language from scratch. pass p oints|s for south, ne for northeast, and so on, plus c for center|are automatically de ned for In this section, we present a few examples to show every picture. This allows us to eliminate some of the principal primitive op erations of FPIC, making the guesswork in the previous example: only minimal use of the programming features of Standard ML. Section 5 gives many more examples, emphasizing the utility of the features of ML in com- val face = circle 2.5; bination with the FPIC primitives. val facecenter = face pt "c"; val lefteye = nose rotate ~90.0 scale 0.7; The most basic primitives are those for drawing sim- val righteye = nose rotate 90.0 scale 0.7; 1 val mouth = doval scaleXY 0.5,0.3; ple shap es and placing them next to one another: face seq nose centeredAt facecenter seq lefteye centeredAt facecenter -- 1.0,~0.7 seq righteye centeredAt facecenter ++ 1.0,0.7 seq mouth centeredAt facecenter -- 0.0,1.5; Named p oints can b e added to a picture. A third Hello! way to pro duce the same \pumpkin face" is to draw the face and name the lo cations of the facial fea- box 1.0 2.0 hseq circle 1.5 vseq tures: label "\\Huge Hello!" oval 2.0 1.0; val face = hseq and vseq represent the op erations of plac- let val f = circle 2.5 ing pictures next to one another, either horizontally val facecenter=fpt"c" or vertically. Note that backslashes inside quotes in namePts f must b e doubled. ["nosepos", facecenter, "lefteyepos", facecenter -- 0.9,~0.8, Pictures can b e moved and otherwise transformed in "righteyepos", facecenter ++ 0.9,0.8, "mouthpos", facecenter -- 0.0,1.5] various ways. In this example, we use ML's name end; de nition facility in the rst line. dtriangle is a face seq nose centeredAt face pt "nosepos" \default triangle;" similarly for doval and dcircle seq lefteye centeredAt face pt "lefteyepos" and dbox later in the pap er. seq righteye centeredAt face pt "righteyepos" seq mouth centeredAt face pt "mouthpos"; 1 App endix A gives a concise overview of ML syntax. Ap- p endix B lists all the FPIC primitives used in the examples in Pictures can b e named as well as p oints. This is this pap er, indicating the typ es of their arguments, whether or not they are in x, and what they return. useful when a numberofpoints on a picture may b e of interest. For example, cell is a \cons cell" of PIC to help answer what we consider the most consisting of twoboxes vertically stacked; for future crucial question in the design pro cess: what do es reference, the individual b oxes are named car and each piece of syntax mean? In ordinary program- cdr, resp ectively: ming terms, syntactic phrases have some intuitive op erational meaning; \circle 2.0" means \drawa circle with radius 2.0." A lesson from denotational semantics is that phrases can b e given precise mean- ings as values of well-de ned sets. It is this notion of \meaning" that we found useful in designing FPIC. We wish to give the reader some idea of the thought pro cess wewent through. val cell = namePic dbox "car" We will call the set in which the meaning of \circle vseq namePic dbox "cdr"; 2.0" resides Picture. The question is, what exactly is in this set? What is a picture? The most obvious In addition to optionally b eing named, subpictures answer is that it is some concrete representation of are automatically numb ered. p nthpic i is the ith a picture, for example, an array of pixels or a list subpicture in p.
Load more

Recommended publications
  • Visualage for Smalltalk Handbook Volume 2: Features
    SG24-2219-00 VisualAge for Smalltalk Handbook Volume 2: Features September 1997 SG24-2219-00 International Technical Support Organization VisualAge for Smalltalk Handbook Volume 2: Features September 1997 IBM Take Note! Before using this information and the product it supports, be sure to read the general information in Appendix A, “Special Notices.” First Edition (September 1997) This edition applies to VisualAge for Smalltalk, Versions 2, 3, and 4, for use with OS/2, AIX, and Microsoft Windows 95/NT. Comments may be addressed to: IBM Corporation, International Technical Support Organization Dept. QXXE Building 80-E2 650 Harry Road San Jose, California 95120-6099 When you send information to IBM, you grant IBM a non-exclusive right to use or distribute the information in any way it believes appropriate without incurring any obligation to you. Copyright International Business Machines Corporation 1997. All rights reserved. Note to U.S. Government Users — Documentation related to restricted rights — Use, duplication or disclosure is subject to restrictions set forth in GSA ADP Schedule Contract with IBM Corp. Contents Preface . xiii How This Redbook Is Organized ....................... xiv ITSO on the Internet ................................ xv VisualAge Support on CompuServe ..................... xvii About the Authors ................................ xvii Acknowledgments . xviii Comments Welcome . xix Chapter 1. AS/400 Connection . 1 Multiple Programs with a Single Remote Procedure Call ......... 1 RPC Part Sets Commit Boundary ........................ 1 Connection Problem with V3R1 ......................... 2 AS/400 Communication Error .......................... 2 Strange Characters on Log-on Window .................... 3 Quick Form from AS/400 Record Classes ................... 3 Communication . 4 Read Next/Previous . 4 SQL Statements . 5 Data Queues and Records ............................ 6 ODBC Requirements .
    [Show full text]
  • Programming-8Bit-PIC
    Foreword Embedded microcontrollers are everywhere today. In the average household you will find them far beyond the obvious places like cell phones, calculators, and MP3 players. Hardly any new appliance arrives in the home without at least one controller and, most likely, there will be several—one microcontroller for the user interface (buttons and display), another to control the motor, and perhaps even an overall system manager. This applies whether the appliance in question is a washing machine, garage door opener, curling iron, or toothbrush. If the product uses a rechargeable battery, modern high density battery chemistries require intelligent chargers. A decade ago, there were significant barriers to learning how to use microcontrollers. The cheapest programmer was about a hundred dollars and application development required both erasable windowed parts—which cost about ten times the price of the one time programmable (OTP) version—and a UV Eraser to erase the windowed part. Debugging tools were the realm of professionals alone. Now most microcontrollers use Flash-based program memory that is electrically erasable. This means the device can be reprogrammed in the circuit—no UV eraser required and no special packages needed for development. The total cost to get started today is about twenty-five dollars which buys a PICkit™ 2 Starter Kit, providing programming and debugging for many Microchip Technology Inc. MCUs. Microchip Technology has always offered a free Integrated Development Environment (IDE) including an assembler and a simulator. It has never been less expensive to get started with embedded microcontrollers than it is today. While MPLAB® includes the assembler for free, assembly code is more cumbersome to write, in the first place, and also more difficult to maintain.
    [Show full text]
  • Cobol Pic Clause Example
    Cobol Pic Clause Example Albuminous and sonsie Scarface never apotheosising nae when Nealon mischarges his hogs. Unlawful Ingmar clips contiguously and super, she revering her cookers benefit symmetrically. Trifoliate Chaim sometimes circularize his breaches see and dilly-dallies so dichotomously! Quetelet index file exactly the coefficient is not confuse the input procedure division resets the rerun in another accept message or paragraphs that? Early cobol example of examples are evaluated one having to pic x when clause is considered useless instructions and date formats will be made quickly than one. After a group item is never reserved words cannot be written under different format you can it occupies in an operational sign printed documentation is suppressed. Because they may be a sample program by requesting a short paragraph in each source item can be greater detail report item is impossible in the records. Exit program using pic n it will be only, or more sections into a pic clause is executed as shown in a file to. Duplicate keys or fetch a call to_char with input call to describe data description during execution of examples of this area b it! We delimit by cobol example illustrates this server outputs data division sections having one. Basic cobol example. The individual file is provided for pic x variables being defined by use of messages. The cobol picture indicates a cobol api to cobol pic clause example. This call function is defined width of the usage is to a table can you explicitly searched last sentence and pic clause scales as steps. No cobol example with clause indicates the pic clause specifies that truncation or.
    [Show full text]
  • PIC Assembly Language for the Complete Beginner
    PIC Assembly Language for the Complete Beginner Michael A. Covington Artificial Intelligence Center The University of Georgia Athens, Georgia 30602-7415 http://www.ai.uga.edu/mc This article appeared in Electronics Now Magazine in 1999 and is reprinted here by permission. Some web addresses have been up- dated but the content has not; you will find that MPLAB, for instance, now looks somewhat different. You may print out this article for personal use but not for further pub- lication. Copyright c 1999 Gernsback Publications, Inc. Copyright c 1999, 2004 Michael A. Covington. These days, the field of electronics is divided into “haves” and “have- nots” – people who can program microcontrollers and people who can’t. If you’re one of the “have-nots,” this article is for you. 1 Microcontrollers are one-chip computers designed to control other equip- ment, and almost all electronic equipment now uses them. The average American home now contains about 100 computers, almost all of which are microcontrollers hidden within appliances, clocks, thermostats, and even automobile engines. Although some microcontrollers can be programmed in C or BASIC, you need assembly language to get the best results with the least expensive micros. The reason is that assembly language lets you specify the exact instructions that the CPU will follow; you can control exactly how much time and memory each step of the program will take. On a tiny computer, this can be important. What’s more, if you’re not already an experienced programmer, you may well find that assembly language is simpler than BASIC or C.
    [Show full text]
  • Extensible Markup Language (XML) 1.0
    REC-xml-19980210 Extensible Markup Language (XML) 1.0 W3C Recommendation 10-Feb-98 This version http://www.w3.org/TR/1998/REC-xml-19980210 http://www.w3.org/TR/1998/REC-xml-19980210.xml http://www.w3.org/TR/1998/REC-xml-19980210.html http://www.w3.org/TR/1998/REC-xml-19980210.pdf http://www.w3.org/TR/1998/REC-xml-19980210.ps Latest version http://www.w3.org/TR/REC-xml Previous version http://www.w3.org/TR/PR-xml-971208 Editors Tim Bray, Textuality and Netscape ([email protected]) Jean Paoli, Microsoft ([email protected]) C. M. Sperberg-McQueen, University of Illinois at Chicago ([email protected]) Abstract The Extensible Markup Language (XML) is a subset of SGML that is completely described in this document. Its goal is to enable generic SGML to be served, received, and processed on the Web in the way that is now possible with HTML. XML has been designed for ease of implementation and for interoperability with both SGML and HTML. Status of this document This document has been reviewed by W3C Members and other interested parties and has been endorsed by the Director as a W3C Recommendation. It is a stable document and may be used as reference material or cited as a normative reference from another document. W3C's role in making the Recommendation is to draw attention to the specification and to promote its widespread deployment. This enhances the functionality and interoperability of the Web. This document specifies a syntax created by subsetting an existing, widely used international text processing standard (Standard Generalized Markup Language, ISO 8879:1986(E) as amended and corrected) for use on the World Wide Web.
    [Show full text]
  • 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
    [Show full text]
  • Domain Specific Languages∗
    Domain Specific Languages∗ Paul Hudak Department of Computer Science Yale University December 15, 1997 1 Introduction When most people think of a programming language they think of a general pur- pose language: one capable of programming any application with relatively the same degree of expressiveness and efficiency. For many applications, however, there are more natural ways to express the solution to a problem than those afforded by general purpose programming languages. As a result, researchers and practitioners in recent years have developed many different domain specific languages, or DSL’s, which are tailored to particular application domains. With an appropriate DSL, one can develop complete application programs for a do- main more quickly and more effectively than with a general purpose language. Ideally, a well-designed DSL captures precisely the semantics of an application domain, no more and no less. Table 1 is a partial list of domains for which DSL’s have been created. As you can see, the list covers quite a lot of ground. For a list of some popular DSL’s that you may have heard of, look at Table 2.1 The first example is a set of tools known as Lex and Yacc which are used to build lexers and parsers, respectively. Thus, ironically, they are good tools for building DSL’s (more on this later). Note that there are several document preparation languages listed; for example, LATEX was used to create the original draft of this article. Also on the list are examples of “scripting languages,” such as PERL, Tcl, and Tk, whose general domain is that of scripting text and file manipulation, GUI widgets, and other software components.
    [Show full text]
  • RM/COBOL Syntax Summary (Second Edition)
    Liant Software Corporation RM/COBOL ® Syntax Summary Second Edition This document provides complete syntax for all RM/COBOL commands, divisions, entries, statements, and other general formats. Use this pamphlet in conjunction with the RM/COBOL Language Reference Manual and the RM/COBOL User's Guide. The RM/COBOL Syntax Summary has been prepared for all implementations of RM/COBOL. Consult the RM/COBOL User's Guide for all appropriate operating system rules and conventions (such as command line invocation). No part of this publication may be reproduced, stored in a retrieval system or transmitted, in any form or by any means, electronic, mechanical, photocopied, recorded, or otherwise, without prior written permission of Liant Software Corporation. The information in this document is subject to change without prior notice. Liant Software Corporation assumes no responsibility for any errors that may appear in this document. Liant reserves the right to make improvements and/or changes in the products and programs described in this guide at any time without notice. Companies, names, and data used in examples herein are fictitious unless otherwise noted. The software described in this document is furnished to the user under a license for a specific number of uses and may be copied (with inclusion of the copyright notice) only in accordance with the terms of such license. Copyright © 1985-2008 by Liant Software Corporation. All rights reserved. Printed in U.S.A. Liant Software Corporation 5914 West Courtyard Dr., Suite 100 Austin, TX 78730-4911 U.S.A. Phone (512) 343-1010 (800) 762-6265 Fax (512) 343-9487 Web site http://www.liant.com RM, RM/COBOL, RM/COBOL-85, Relativity, Enterprise CodeBench, RM/InfoExpress, RM/Panels, VanGui Interface Builder, CodeWatch, CodeBridge, Cobol-WOW, WOW Extensions, InstantSQL, Xcentrisity, XML Extensions, Liant, and the Liant logo are trademarks or registered trademarks of Liant Software Corporation.
    [Show full text]
  • Semantics-Driven DSL Design*
    Semantics-Driven DSL Design* Martin Erwig and Eric Walkingshaw School of EECS, Oregon State University, USA ABSTRACT Convention dictates that the design of a language begins with its syntax. We argue that early emphasis should be placed instead on the identification of general, compositional semantic domains, and that grounding the design process in semantics leads to languages with more consistent and more extensible syntax. We demonstrate this semantics-driven design process through the design and implementation of a DSL for defining and manipulating calendars, using Haskell as a metalanguage to support this discussion. We emphasize the importance of compositionality in semantics-driven language design, and describe a set of language operators that support an incremental and modular design process. INTRODUCTION Despite the lengthy history and recent popularity of domain-specific languages, the task of actually designing DSLs remains a difficult and under-explored problem. This is evidenced by the admission of DSL guru Martin Fowler, in his recent book on DSLs, that he has no clear idea of how to design a good language (2010, p. 45). Instead, recent work has focused mainly on the implementation of DSLs and supporting tools, for example, through language workbenches (Pfeiffer & Pichler, 2008). This focus is understandable—implementing a language is a structured and well-defined problem with clear quality criteria, while language design is considered more of an art than an engineering task. Furthermore, since DSLs have limited scope and are often targeted at domain experts rather than professional programmers, general-purpose language design criteria may not always be applicable to the design of DSLs, complicating the task even further (Mernik et al., 2005).
    [Show full text]
  • Software II: Principles of Programming Languages
    Software II: Principles of Programming Languages Lecture 6 – Data Types Some Basic Definitions • A data type defines a collection of data objects and a set of predefined operations on those objects • A descriptor is the collection of the attributes of a variable • An object represents an instance of a user- defined (abstract data) type • One design issue for all data types: What operations are defined and how are they specified? Primitive Data Types • Almost all programming languages provide a set of primitive data types • Primitive data types: Those not defined in terms of other data types • Some primitive data types are merely reflections of the hardware • Others require only a little non-hardware support for their implementation The Integer Data Type • Almost always an exact reflection of the hardware so the mapping is trivial • There may be as many as eight different integer types in a language • Java’s signed integer sizes: byte , short , int , long The Floating Point Data Type • Model real numbers, but only as approximations • Languages for scientific use support at least two floating-point types (e.g., float and double ; sometimes more • Usually exactly like the hardware, but not always • IEEE Floating-Point Standard 754 Complex Data Type • Some languages support a complex type, e.g., C99, Fortran, and Python • Each value consists of two floats, the real part and the imaginary part • Literal form real component – (in Fortran: (7, 3) imaginary – (in Python): (7 + 3j) component The Decimal Data Type • For business applications (money)
    [Show full text]
  • MPLAB XC32 C/C++ Compiler User's Guide
    MPLAB® XC32 C/C++ Compiler User’s Guide 2012-2016 Microchip Technology Inc. DS50001686J Note the following details of the code protection feature on Microchip devices: • Microchip products meet the specification contained in their particular Microchip Data Sheet. • Microchip believes that its family of products is one of the most secure families of its kind on the market today, when used in the intended manner and under normal conditions. • There are dishonest and possibly illegal methods used to breach the code protection feature. All of these methods, to our knowledge, require using the Microchip products in a manner outside the operating specifications contained in Microchip’s Data Sheets. Most likely, the person doing so is engaged in theft of intellectual property. • Microchip is willing to work with the customer who is concerned about the integrity of their code. • Neither Microchip nor any other semiconductor manufacturer can guarantee the security of their code. Code protection does not mean that we are guaranteeing the product as “unbreakable.” Code protection is constantly evolving. We at Microchip are committed to continuously improving the code protection features of our products. Attempts to break Microchip’s code protection feature may be a violation of the Digital Millennium Copyright Act. If such acts allow unauthorized access to your software or other copyrighted work, you may have a right to sue for relief under that Act. Information contained in this publication regarding device Trademarks applications and the like is provided only for your convenience The Microchip name and logo, the Microchip logo, AnyRate, and may be superseded by updates.
    [Show full text]
  • COBOL V6 Migration Best Practices for COBOL V6 Migration Examples of Invalid Data How to Prepare for COBOL V6 Before You Buy Resources
    Migrating to Enterprise COBOL V6 Mike Chase June 5th, 2018 Migration to Enterprise COBOL V6 What, when, and why of COBOL Migration A brief history of COBOL compilers on z/OS What is different about COBOL V6 migration Best practices for COBOL V6 Migration Examples of invalid data How to prepare for COBOL V6 before you buy Resources 2 What, when, and why of COBOL Migration What § Enterprise COBOL for z/OS, V5 and Enterprise COBOL for z/OS, V6 § COBOL compilers with new generation code generator and optimizer When § COBOL V5.1: 2013, V5.2: 2015 – COBOL V5 EOM Sept 11, 2017 (announced Dec 6, 2016) § COBOL V6.1: 2016, V6.2: 2017 – Migrating to V6 is the same as migrating to V5, we will only say V6 in this talk Why § Exploit the latest hardware § Give performance improvement to COBOL applications without source code changes § Less MSUs, save money! 3 What, when, and why of COBOL Migration How to save MSUs? § Migrate to (recompile with) Enterprise COBOL for z/OS, V6 What's different than previous migrations over the last 30 years? § New code generator could produce more optimal code than prior versions of COBOL. § You can get different generated code sequences for the same COBOL source. –Good: Save MSUs (MIPS, CPU) –Not so good: More optimal instructions can process invalid data differently, causing different runtime behavior 4 Optimization of COBOL programs Can IBM improve performance of older COBOL applications without recompiling? § Yes! Automatic Binary Optimizer (ABO) optimizes the executable (either Load Module or Program Object), without using the source § ABO uses the same technology as Enterprise COBOL V6 § Useful for programs..
    [Show full text]