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CSC 272 - Software II: Principles of Programming Languages
CSC 272 - Software II: Principles of Programming Languages Lecture 1 - An Introduction What is a Programming Language? • A programming language is a notational system for describing computation in machine-readable and human-readable form. • Most of these forms are high-level languages , which is the subject of the course. • Assembly languages and other languages that are designed to more closely resemble the computer’s instruction set than anything that is human- readable are low-level languages . Why Study Programming Languages? • In 1969, Sammet listed 120 programming languages in common use – now there are many more! • Most programmers never use more than a few. – Some limit their career’s to just one or two. • The gain is in learning about their underlying design concepts and how this affects their implementation. The Six Primary Reasons • Increased ability to express ideas • Improved background for choosing appropriate languages • Increased ability to learn new languages • Better understanding of significance of implementation • Better use of languages that are already known • Overall advancement of computing Reason #1 - Increased ability to express ideas • The depth at which people can think is heavily influenced by the expressive power of their language. • It is difficult for people to conceptualize structures that they cannot describe, verbally or in writing. Expressing Ideas as Algorithms • This includes a programmer’s to develop effective algorithms • Many languages provide features that can waste computer time or lead programmers to logic errors if used improperly – E. g., recursion in Pascal, C, etc. – E. g., GoTos in FORTRAN, etc. Reason #2 - Improved background for choosing appropriate languages • Many professional programmers have a limited formal education in computer science, limited to a small number of programming languages. -
Note Quiz 1 K All 10 Questions Ise File Main Sy Thay Note Handouts Main Note Keyword Ko Search Krien Important Points Hain Jin Ko Lazmi Yaad Krna Hy
Note Quiz 1 k all 10 questions ise file main sy thay Note handouts main note keyword ko search krien important points hain jin ko lazmi yaad krna hy. Ada discriminate types is similar to . C/C++ pointer C/C++ union C/C++ reference All of the given Page # 52 - My Ok The block structure feature of ALGOL60 has scope. No Local Universal Global Page # 26 – My Ok Unlike C/C++, Ada can have _____ within functions/procedures. Objects Functions/procedures Events Parameters Page # 58 – My Ok In the Decimal fixed point type, the distance between values is implemented as a power of 2 10 8 16 Page # 50 – My Ok Function must have at least ______ return statement. Three Two One Four Page # 57 – My Ok Every function must have at least one return statement. A procedure is not required to have any return statements. The expression in a function's return statement must evaluate to a type that matches the return type in the function's declaration. ______ operations must have one of its parameters of the tagged type. Concurrent Synchronized Primitive Generic Page # 59 – My Ok An understanding of implementation issues leads to a/an ______ of why languages are designed the way they are. Uncertainty Understanding Misunderstanding Confusion Page # 5 – My Ok ________ has an efficient use of processor and memory. Plankul Kool LISP CORBA C++ Imperative programming languages are the direct result of . Charles Babbage engine Logic or list program languages. Von Neumann architecture Language application domain Page # 22 – My Ok Following are imperative languages EXCEPT LISP C FORTRAN PASCAL Page # 22 – My Ok Which statement is true from programming language evolution perspective about 1970's era? Analysis and elaboration era Era of effective software technology Era of object oriented programming languages Era of discovery and description Page # 30 – My Ok SNOBOL language questions starts from here Variable name in SNOBOL may not be longer than . -
Regular Expressions
Regular Expressions A regular expression describes a language using three operations. Regular Expressions A regular expression (RE) describes a language. It uses the three regular operations. These are called union/or, concatenation and star. Brackets ( and ) are used for grouping, just as in normal math. Goddard 2: 2 Union The symbol + means union or or. Example: 0 + 1 means either a zero or a one. Goddard 2: 3 Concatenation The concatenation of two REs is obtained by writing the one after the other. Example: (0 + 1) 0 corresponds to f00; 10g. (0 + 1)(0 + ") corresponds to f00; 0; 10; 1g. Goddard 2: 4 Star The symbol ∗ is pronounced star and means zero or more copies. Example: a∗ corresponds to any string of a’s: f"; a; aa; aaa;:::g. ∗ (0 + 1) corresponds to all binary strings. Goddard 2: 5 Example An RE for the language of all binary strings of length at least 2 that begin and end in the same symbol. Goddard 2: 6 Example An RE for the language of all binary strings of length at least 2 that begin and end in the same symbol. ∗ ∗ 0(0 + 1) 0 + 1(0 + 1) 1 Note precedence of regular operators: star al- ways refers to smallest piece it can, or to largest piece it can. Goddard 2: 7 Example Consider the regular expression ∗ ∗ ((0 + 1) 1 + ")(00) 00 Goddard 2: 8 Example Consider the regular expression ∗ ∗ ((0 + 1) 1 + ")(00) 00 This RE is for the set of all binary strings that end with an even nonzero number of 0’s. -
Technical Standard COBOL Language
Technical Standard COBOL Language NICAL H S C T A E N T D A R D [This page intentionally left blank] X/Open CAE Specification COBOL Language X/Open Company, Ltd. December 1991, X/Open Company Limited All rights reserved. No part of this publication may be reproduced, stored in a retrieval system, or transmitted, in any form or by any means, electronic, mechanical, photocopying, recording or otherwise, without the prior permission of the copyright owners. X/Open CAE Specification COBOL Language ISBN: 1 872630 09 X X/Open Document Number: XO/CAE/91/200 Set in Palatino by X/Open Company Ltd., U.K. Printed by Maple Press, U.K. Published by X/Open Company Ltd., U.K. Any comments relating to the material contained in this document may be submitted to X/Open at: X/Open Company Limited Apex Plaza Forbury Road Reading Berkshire, RG1 1AX United Kingdom or by Electronic Mail to: [email protected] X/Open CAE Specification (1991) Page : ii COBOL Language Contents COBOL LANGUAGE Chapter 1 INTRODUCTION 1.1 THE X/OPEN COBOL DEFINITION 1.2 HISTORY OF THIS DOCUMENT 1.3 FORMAT OF ENTRIES 1.3.1 Typographical Conventions 1.3.2 Terminology Chapter 2 COBOL DEFINITION 2.1 GENERAL FORMAT FOR A SEQUENCE OF SOURCE PROGRAMS 2.2 GENERAL FORMAT FOR NESTED SOURCE PROGRAMS 2.2.1 Nested-Source-Program 2.3 GENERAL FORMAT FOR IDENTIFICATION DIVISION 2.4 GENERAL FORMAT FOR ENVIRONMENT DIVISION 2.5 GENERAL FORMAT FOR SOURCE-COMPUTER-ENTRY 2.6 GENERAL FORMAT FOR OBJECT-COMPUTER-ENTRY 2.7 GENERAL FORMAT FOR SPECIAL-NAMES-CONTENT 2.8 GENERAL FORMAT FOR FILE-CONTROL-ENTRY 2.8.1 -
ED027743.Pdf
DOCUMENT RESUME ED 027 743 EM 007 134 By-Fasana, Paul J., Ed.; Shank, Russell, Ed. Tutorial on Generalized Programming Language s and Systems. Instructor Edition. American Society for Information Science, Washington, D.C. Spons Agency-National Science Foundation, Washington, D.C. Pub Date Jul 68 Grant- F -NSF -GN -657 Note-65p.; Manual based on materials prepared and presented by Thomas K. Burgess and others at the Annual Convention of the American Society for Information Science (New York, October 22-26, 1967) EDRS Price MF-$0.50 HC-$3.35 Descriptors-*Computer Science, *Computer Science Education, Information Retrieval, Information Storage, *Manuals Identifiers-COBOL, FORTRAN, PL I, SNOBOL This instructor's manual is a comparative analysis and review of the various computer programing languagescurrentlyavailable andtheircapabilitiesfor performing text manipulation, information storage, and data retrieval tasks. Based on materials presented at the 1967 Convention of the American Society for Information Science,themanualdescribes FORTRAN, a language designedprimarilyfor mathematicalcomputation;SNOBOL, alist-processinglanguagedesignedfor information retrieval application; COBOL, a business oriented language; and PL/L a new language incorporating many of the desirable features of FORTRAN andCOBOL but as yet implemented only for the IBM 360 computer system. (TI) U.S. DEPARTMENT OF HEALTH, EDUCATION & WELFARE OFFICE OF EDUCATION Pek THIS DOCUMENT HAS BEEN REPRODUCED EXACTLY AS RECEIVED FROM THE N. PERSON OR ORGANIZATION ORIGINATING IT.POINTS Of VIEW OR OPINIONS rJ STATED DO NOT NECESSARILY REPRESENT OFFICIAL OFFICE OF EDUCATION TUTORIAL ON POSITION OR POLICY. GENERALIZED PROGRAMMING LANGUAGES AND SYSTEMS Instructor Edition. Edited by Paul J. Fasana Columbia University Libraries New York, N. Y. and Russell Shank The Smithsonian Institution Washington, D. -
CMPSCI 250 Lecture
CMPSCI 250: Introduction to Computation Lecture #29: Proving Regular Language Identities David Mix Barrington 6 April 2012 Proving Regular Language Identities • Regular Language Identities • The Semiring Axioms Again • Identities Involving Union and Concatenation • Proving the Distributive Law • The Inductive Definition of Kleene Star • Identities Involving Kleene Star • (ST)*, S*T*, and (S + T)* Regular Language Identities • In this lecture and the next we’ll use our new formal definition of the regular languages to prove things about them. In particular, in this lecture we’ll prove a number of regular language identities, which are statements about languages where the types of the free variables are “regular expression” and which are true for all possible values of those free variables. • For example, if we view the union operator + as “addition” and the concatenation operator ⋅ as “multiplication”, then the rule S(T + U) = ST + SU is a statement about languages and (as we’ll prove today) is a regular language identity. In fact it’s a language identity as regularity doesn’t matter. • We can use the inductive definition of regular expressions to prove statements about the whole family of them -- this will be the subject of the next lecture. The Semiring Axioms Again • The set of natural numbers, with the ordinary operations + and ×, forms an algebraic structure called a semiring. Earlier we proved the semiring axioms for the naturals from the Peano axioms and our inductive definitions of + and ×. It turns out that the languages form a semiring under union and concatenation, and the regular languages are a subsemiring because they are closed under + and ⋅: if R and S are regular, so are R + S and R⋅S. -
Some Aspects of Semirings
Appendix A Some Aspects of Semirings Semirings considered as a common generalization of associative rings and dis- tributive lattices provide important tools in different branches of computer science. Hence structural results on semirings are interesting and are a basic concept. Semi- rings appear in different mathematical areas, such as ideals of a ring, as positive cones of partially ordered rings and fields, vector bundles, in the context of topolog- ical considerations and in the foundation of arithmetic etc. In this appendix some algebraic concepts are introduced in order to generalize the corresponding concepts of semirings N of non-negative integers and their algebraic theory is discussed. A.1 Introductory Concepts H.S. Vandiver gave the first formal definition of a semiring and developed the the- ory of a special class of semirings in 1934. A semiring S is defined as an algebra (S, +, ·) such that (S, +) and (S, ·) are semigroups connected by a(b+c) = ab+ac and (b+c)a = ba+ca for all a,b,c ∈ S.ThesetN of all non-negative integers with usual addition and multiplication of integers is an example of a semiring, called the semiring of non-negative integers. A semiring S may have an additive zero ◦ defined by ◦+a = a +◦=a for all a ∈ S or a multiplicative zero 0 defined by 0a = a0 = 0 for all a ∈ S. S may contain both ◦ and 0 but they may not coincide. Consider the semiring (N, +, ·), where N is the set of all non-negative integers; a + b ={lcm of a and b, when a = 0,b= 0}; = 0, otherwise; and a · b = usual product of a and b. -
The Evolution of Lua
The Evolution of Lua Roberto Ierusalimschy Luiz Henrique de Figueiredo Waldemar Celes Department of Computer Science, IMPA–Instituto Nacional de Department of Computer Science, PUC-Rio, Rio de Janeiro, Brazil Matematica´ Pura e Aplicada, Brazil PUC-Rio, Rio de Janeiro, Brazil [email protected] [email protected] [email protected] Abstract ing languages offer associative arrays, in no other language We report on the birth and evolution of Lua and discuss how do associative arrays play such a central role. Lua tables it moved from a simple configuration language to a versatile, provide simple and efficient implementations for modules, widely used language that supports extensible semantics, prototype-based objects, class-based objects, records, arrays, anonymous functions, full lexical scoping, proper tail calls, sets, bags, lists, and many other data structures [28]. and coroutines. In this paper, we report on the birth and evolution of Lua. We discuss how Lua moved from a simple configuration Categories and Subject Descriptors K.2 [HISTORY OF language to a powerful (but still simple) language that sup- COMPUTING]: Software; D.3 [PROGRAMMING LAN- ports extensible semantics, anonymous functions, full lexical GUAGES] scoping, proper tail calls, and coroutines. In §2 we give an overview of the main concepts in Lua, which we use in the 1. Introduction other sections to discuss how Lua has evolved. In §3 we re- late the prehistory of Lua, that is, the setting that led to its Lua is a scripting language born in 1993 at PUC-Rio, the creation. In §4 we relate how Lua was born, what its original Pontifical Catholic University of Rio de Janeiro in Brazil. -
Theme and Variations on the Concatenation Product
Theme and variations on the concatenation product Jean-Eric´ Pin1⋆ LIAFA, University Paris-Diderot and CNRS, France. Abstract. The concatenation product is one of the most important op- erations on regular languages. Its study requires sophisticated tools from algebra, finite model theory and profinite topology. This paper surveys research advances on this topic over the last fifty years. The concatenation product plays a key role in two of the most important results of automata theory: Kleene’s theorem on regular languages [23] and Sch¨utzen- berger’s theorem on star-free languages [60]. This survey article surveys the most important results and tools related to the concatenation product, including connections with algebra, profinite topology and finite model theory. The paper is organised as follows: Section 1 presents some useful algebraic tools for the study of the concatenation product. Section 2 introduces the main definitions on the product and its variants. The classical results are summarized in Section 3. Sections 4 and 5 are devoted to the study of two algebraic tools: Sch¨utzenberger products and relational morphisms. Closure properties form the topic of Section 6. Hierarchies and their connection with finite model theory are presented in Sections 7 and 8. Finally, new directions are suggested in Section 9. 1 The instruments This section is a brief reminder on the algebraic notions needed to study the con- catenation product: semigroups and semirings, syntactic ordered monoids, free profinite monoids, equations and identities, varieties and relational morphisms. More information can be found in [1–3,18,35,42,45]. 1.1 Semigroups and semirings If S is a semigroup, the set P(S) of subsets of S is also a semiring, with union as addition and multiplication defined, for every X, Y ∈P(S), by XY = {xy | x ∈ X,y ∈ Y } In this semiring, the empty set is the zero and for this reason, is denoted by 0. -
Mal E Init N Synt X Cobol
BeMA EUROPEAN CO~IPUTER ~lANUFACTURERS ASSOCIATION MAL E INIT N of the SYNT X COBOL eptelnber ] 970 Free copies of this document are available from ECMA, European Computer Manufacturers Association, 114 Rue du Rhone - 1204 Geneva (Switzerland) EeMA EUROPEAN COMPUTER MANUFACTURERS ASSOCIATION FORMAL DEFINITION of the SYNTAX OF COBOL Septenlber 1970 FORMAL DEFINITION of the SYNTAX OF COBOL - i - CONTENTS Page PREFACE ix INTRODUCTION TO THE NOTATION xiii FORMAL DEFINITION OF COBOL SYNTAX G. Syntactic Definitions of General Nature EMPTY 1 COBOL GRAPHICS 2 COBOL CONTROLS 4 SOME FREQUENTLY USED SEPARATORS 5 WORD 6 PROPER NONNUMERIC LITERAL 7 PROPER NUMERIC LITERAL 8 FIGURATIVE CONSTANT 9 LITERAL 10 ARITHMETIC OPERATOR 11 PROPER RELATIONAL OPERATOR 12 PICTURE CHARACTER STRING 13 COMMENT STRING 14 OTHER LANGUAGE STRING 15 T. COBOL Text SEPARATORS 16 GENERALIZED CHARACTER STRING 17 STRUCTURE OF COBOL TEXT 18 - ii - Page N. Names defined by the Imp1ementors HARDWARE NAMES 19 OTHER NAMES 20 C. COBOL Program COBOL PROGRAM STRUCTURE 21 I. Identification Division IDENTIFICATION DIVISION STRUCTURE 22 PROGRAM-ID PARAGRAPH 23 DATE COMPILED PARAGRAPH 24 OTHER PARAGRAPHS 2S COt~ENT PAP~GRAPH BODY 26 E. Environment Division ENVIRONMENT DIVISION STRUCTURE 27 CONFIGURATION SECTION STRUCTURE 28 INPUT-OUTPUT SECTION STRUCTURE 29 SOURCE COMPUTER PARAGRAPH 30 OBJECT COMPUTER PARAGRAPH 31 SEGMENT LIMIT CLAUSE 32 SPECIAL-NAMES PARAGRAPH 33 SPECIAL-NAMES CLAUSE 34 CURRENCY-SIGN CLAUSE 37 DECIMAL-POINT CLAUSE 38 FILE-CONTROL PARAGRAPH 39 SELECT CLAUSE 41 ASSIGN CLAUSE 42 MULTIPLE REEL/UNIT CLAUSE 43 ALTERNATE AREA CLAUSE 44 FILE-LIMIT CLAUSE 4S - iii - Page ACCESS MODE CLAUSE 46 PROCESSING MODE CLAUSE 47 KEY CLAUSE 48 I-O-CONTROL PARAGRAPH 49 RERUN CLAUSE 50 SAME CLAUSE 51 MULTIPLE FILE CLAUSE 52 D. -
SNOBOL-Tone (ST) - a Sound Pattern-Matching Programming Language
SNOBOL-Tone (ST) - A Sound Pattern-Matching Programming Language Dan Ophir(1) and Dotan Dekel(2) AFEKA, Tel-Aviv Academic College of Engineering, Tel Aviv, Israel (1) [email protected] (2) [email protected] Abstract Keywords: Interpreter, Fast Fourier Transform, Pattern- The proposed programming language, matching, MLAT – Multi Level Adaptive SNOBOL-Tone, performs sound matching in a Technique. given sound stream. This is analogous to pattern-matching of substrings in a given 1. Introduction string, as is done in the SNOBOL language [1]. SNOBOL-Tone is a Domain Specific One way to perform the SNOBOL-Tone pattern Language (DSL) for the specific purpose of matching of a spoken text is to transcribe the treating tones, sounds and signals [5]. Another text into written text followed by regular language that has a similar function is CSound SNOBOL pattern matching [2]. However, [6]. Csound is a computer programming when the sound stream is not a spoken stream language for sound, also known as a sound another solution is needed. SNOBOL-Tone is compiler or an audio programming language, designed to provide such a solution. or more precisely, an audio DSL. It is called SNOBOL-Tone integrates three scientific Csound because it is written in C, as opposed domains: to some of its predecessors. 1. Computer science – creating 2. SNOBOL Concepts compilers and interpreters; 2. Electronic engineering – building SNOBOL [1] is a string pattern matching filters of various frequencies; programming language based on a single 3. Applied mathematics – Fourier statement: transformations, wavelets, optimization of algebraic expressions (1) <label>: <subject> <pattern> = and multi-level-adaptive-techniques <object> :S(label1)F(label2) to accelerate various filtering algorithms [3]. -
Introduction to Object-Oriented Programming
QUIZ How could we disable the automatic creation of copy- constructors pre-C++11? What syntax feature did C++11 introduce to make the disabling clearer and more permanent? • Give a code example. QUIZ How is the overloaded assignment operator different from all other overloaded operators in C++? QUIZ Show in a code example how to disable the automatic creation of the overloaded assignment operator post- C++11. The class is named Foo. Ch. 14: Inheritance & Composition Remember composition Composition If embedded object is private, it will be accessed through member (or friend) functions Composition – multi-level example Draw the UML diagram, as learned in ch.1! Inheritance Base class, from which Y inherits UML diagram Inheritance The default is private inheritance During inheritance, everything defaults to private. If the base class were not preceded by public, it would mean that all of the members of the base class, private and public would be private in the derived class. Examples on next slide Explaining public and private in inheritance (see protected later!) Inheritance – adding new functions change( ) ↔ we can add completely new functions. Inheritance – redefining functions set( ) ↔ we can redefine functions from the base class. If function is redefined, we can still call the base-class version using the scope resolution operator! Inheritance – redefining functions A note on language: redefining functions in a derived class is mostly referred to today as overriding; this includes the C++ standards. (Redefining is used when we talk about typedef or namespaces.) Unfortunately, the matter is further muddled by the existence of the override identifier (since C++11 – it applies only to virtual functions).