1. Evolution of the Major Programming Languages Chapter 2: Evolution of the Major Programming Languages Lectures # 5

2. Evolution of the Major Programming Languages Chapter 2: Evolution of the Major Programming Languages The IBM 704 and Fortran Functional Programming: Lisp The First Step Toward Sophistication: Algol 60 Computerizing Business Records: COBOL The Beginnings of Timesharing: BASIC Everything for Everybody: PL/I Two Early Dynamic Languages: APL and SNOBOL The Beginnings of Data Abstraction: SIMULA 67 Orthogonal Design: ALGOL 68 Some Early Descendants of the ALGOLs 2Chapter 2: Evolution of the Major Programming Languages

3. Evolution of the Major Programming Languages Chapter 2: Evolution of the Major Programming Languages Programming Based on Logic: Prolog History’s Largest Design Effort: Ada Object-Oriented Programming: Smalltalk Combining Imperative and Object-Oriented Programming: C++ An Imperative-Based Object-Oriented Language: Java Scripting Languages for the Web A C-Based Language for the New Millennium: C# Markup/Programming Hybrid Languages 3Chapter 2: Evolution of the Major Programming Languages

5. Fortran IBM 704 and Fortran Fortran 0 : 1954 - not implemented Fortran I : 1957  Designed for IBM 704.  First implemented and compiled high level language.  Variable names could have up to six characters.  I/O formatting.  User-defined subprograms.  IF selection statement.  DO loop statement.  No data typing statements. Fortran II Fortran II : 1958  Independent compilation of subprograms.  Fixed the bugs in Fortran I. 5Chapter 2: Evolution of the Major Programming Languages

6. Fortran IBM 704 and Fortran (cont.) Fortran IV : 1960-1962  Explicit type declarations.  Logical IF selection statement.  Passing Subprograms as parameters to other subprograms. Fortran 77  Character string handling.  Logical loop control statement.  IF-THEN-ELSE statements. Fortran 9X  Dynamic arrays and Pointers.  Recursion.  CASE statement.  Parameter type checking. 6Chapter 2: Evolution of the Major Programming Languages

7. LISP Functional Programming: LISP LIST Processing language. Needed by AI researchers to:  Process data in lists (rather than arrays).  Symbolic computation (rather than numeric). Only two data types: atoms and lists. Syntax is based on lambda calculus. 7Chapter 2: Evolution of the Major Programming Languages

8. Other Functional Programming Scheme: Scheme: Developed at MIT in mid 1970s.  Small size.  Extensive use of static scoping.  Treatment of functions as first-class entities (functions can be assigned to variables, passed as parameters, and returned as values).  Simple syntax make it ideal for educational applications. COMMON LISP COMMON LISP  An effort to combine features of several dialects of LISP into a single language.  Large and complex language. ML, Miranda, and Haskell ML, Miranda, and Haskell are related languages. 8Chapter 2: Evolution of the Major Programming Languages

9. The First Step Toward Sophistication: Algol 60 (Algorithmic Language) Algol 58: Algol 58: Added several new constructs to Fortran.  Identifiers could be any length.  Arrays could have any number of subscripts.  Parameters were separated by mode (in & out).  Compound statements (begin... end). Algol 60 Algol 60  Two parameter passing methods.  Subprogram recursion.  Stack-dynamic arrays.  First machine-independent language.  First language whose syntax was formally defined (BNF). 9Chapter 2: Evolution of the Major Programming Languages

10. Computerizing Business Records: COBOL Based on FLOW-MATIC features such as:  Names up to 12 characters, with embedded hyphens.  English names for arithmetic operators.  Data and code were completely separate. Hierarchical data structures (records). Nested selection statements. Long names (up to 30 characters), with hyphens. Separate data division. 10Chapter 2: Evolution of the Major Programming Languages

11. The Beginnings of Timesharing: BASIC Based on Fortran with some influence from Algol 60. Easy to learn and use for non-science students. Pleasant and friendly. Free and private access. User time is more important than computer time. Current: Visual BASIC. First widely used language with time sharing. 11Chapter 2: Evolution of the Major Programming Languages

12. Everything for Everybody: PL/I Designed to be used in both business and scientific applications. First allowed to create concurrently executing subprograms, but it was poorly developed in PL/I. First exception handling. Used recursion. First pointers were included as a data type. 12Chapter 2: Evolution of the Major Programming Languages

13. Two Early Dynamic Languages: APL and SNOBOL APL APL (A Programming Language)  Characterized by dynamic typing and dynamic storage allocation  Variables are untyped. A variable acquires a type when it is assigned a value.  Storage is allocated to a variable when it is assigned a value.  Highly expressive (many operators, for both scalars and arrays of various dimensions). SNOBOL SNOBOL  Designed as a string manipulation (text processing) language.  Powerful operators for string pattern matching.  Slower than alternative languages. 13Chapter 2: Evolution of the Major Programming Languages

14. The Beginnings of Data Abstraction: SIMULA 67 Designed primarily for system simulation. Based on ALGOL 60 and SIMULA I. New features:  Coroutines - a kind of subprograms: Subprograms are allowed to restart at the position where they previously stopped.  Implemented in a structure called a class.  Classes are the basis for data abstraction.  Classes are structures that include both local data and functions. 14Chapter 2: Evolution of the Major Programming Languages

15. Orthogonal Design: ALGOL 68 Design is based on the concept of orthogonality:  A few principle concepts, few combining mechanisms. Had strong influence on subsequent languages, such as Pascal, C, Modula 2, Ada, C++, Java, and Perl. New features:  User-defined data structures.  Reference types.  Dynamic arrays (called flex arrays). 15Chapter 2: Evolution of the Major Programming Languages

16. Some Early Descendants of the ALGOLs Pascal Pascal - 1971  Designed for teaching structured programming.  Small, simple, nothing really new.  Largest impact on teaching programming. From mid-1970s until the late 1990s. C C – 1972  Evolved primarily from BCLP, B, but also ALGOL 68.  Powerful set of operators, but poor type checking.  Initially spread through UNIX.  Many areas of application. 16Chapter 2: Evolution of the Major Programming Languages

17. Programming Based on Logic: Prolog Based on formal logic. Non-procedural. Can be summarized as being an intelligent database system that uses an inference process to infer the truth of given queries. Highly inefficient, small application areas. 17Chapter 2: Evolution of the Major Programming Languages

18. History’s Largest Design Effort: Ada New features:  Packages - support for data abstraction.  Exception handling -  Generic program units.  Concurrency - through the tasking model. Ada 95 Ada 95 (began in 1988)  Support for OOP through type derivation.  Better control mechanisms for shared data.  New concurrency features.  More flexible libraries. 18Chapter 2: Evolution of the Major Programming Languages

19. Object-Oriented Programming: Smalltalk First full implementation of an object-oriented language (data abstraction, inheritance, and dynamic type binding). Pioneered the graphical user interface design. Promoted OOP. 19Chapter 2: Evolution of the Major Programming Languages

20. Combining Imperative and Object- Oriented Programming: C++ Evolved from C and SIMULA 67. Facilities for object-oriented programming, taken partially from SIMULA 67. Provides exception handling. A large and complex language, in part because it supports both procedural and OO programming. Rapidly grew in popularity, along with OOP. ANSI standard approved in November 1997. Microsoft’s version (released with.NET in 2002). 20Chapter 2: Evolution of the Major Programming Languages

21. Related OOP Languages Eiffel Eiffel (designed by Bertrand Meyer - 1992)  Not directly derived from any other language.  Smaller and simpler than C++, but still has most of the power.  Lacked popularity of C++ because many C++ enthusiasts were already C programmers. Delphi Delphi (Borland)  Pascal plus features to support OOP.  More elegant and safer than C++. 21Chapter 2: Evolution of the Major Programming Languages

22. An Imperative-Based Object- Oriented Language: Java Based on C++  Significantly simplified (does not include struct, union, enum, pointer).  Supports only OOP.  Has references, but not pointers.  Includes support for applets and a form of concurrency. 22Chapter 2: Evolution of the Major Programming Languages

23. An Imperative-Based Object- Oriented Language: Java (cont.) Java Evaluation:  Eliminated unsafe features of C++.  Concurrency features.  Libraries for applets, GUIs, database access.  Portable: Java Virtual Machine concept, JIT compilers.  Widely used for WWW pages.  Use for other areas increased faster than any other language.  Most recent version, 5.0, released in 2004. 23Chapter 2: Evolution of the Major Programming Languages

24. Scripting Languages for the Web JavaScript JavaScript  A joint venture of Netscape and Sun Microsystems.  Used in Web programming (client side) to create dynamic HTML documents.  Related to Java only through similar syntax. PHP PHP  PHP: Hypertext Preprocessor.  Used for Web applications (server side); produces HTML code as output. Python Python  An OO interpreted scripting language.  Type checked but dynamically typed. 24Chapter 2: Evolution of the Major Programming Languages

25. A C-Based Language for the New Millennium: C# Part of the.NET development platform. Based on C++, Java, and Delphi. Provides a language for component-based software development. All.NET languages (C#, Visual BASIC.NET, Managed C++, J#.NET, and Jscript.NET) use Common Type System (CTS), which provides a common class library. Likely to become widely used. 25Chapter 2: Evolution of the Major Programming Languages

26. Markup/Programming Hybrid Languages XSLT XSLT  eXtensible Markup Language (XML): a metamarkup language.  eXtensible Stylesheet Language Transformation (XSLT) transforms XML documents to XHTML documents for display.  Programming constructs (e.g., looping). JSP JSP  Java Server Pages: a collection of technologies to support dynamic Web documents.  Servlet: a Java program that resides on a Web server; servlet’s output is displayed by the browser. 26Chapter 2: Evolution of the Major Programming Languages