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Computer Languages

by Lee Alexander

The broadest definition I could find for language was a means of communication. Different languages for different nationalities, spoken and written languages for the trades and science (otherwise known as jargon), all bespeak of communication among humans or between species. A between-species example would be teaching an animal to respond to verbal commands by a reward system. What reward can you give a machine? Computers have certainly changed the world and a new form of linguistics is not the least of it.

Computer languages exist in genres: programming, operating systems, drivers, macros, machine language, etc. Languages come and go but, for the most part, they grow from common roots and have great deal of similarity. This is particularly true for programming languages. Hardware innovations can give rise to new algorithms; witness the GUI (Graphics User Interface) which has been a major factor in supplanting the text-only languages of the past: APL (A Programming Language), BASIC (Beginners All-purpose Symbolic Instruction Code), COBOL (Common Business Oriented Language), FORTRAN (Formula Translator). Does this list make you wonder, which came first, the name or the acronym?

A matter of definition – a gloss is the application of the first and/or primary letters of a term to create a “word;” if that word is pronounceable, it is an acronym. One of the most famous acronyms is radar (RAdio Detection And Ranging). This term is now so common it is accepted in lower case. By the way, try pronouncing RDR as a word. To be anonymous, you “go under the radar.”

High level computer languages are those that are (almost) readable as opposed to machine level languages dedicated to a particular system. Even Assembly Language, a fast and fundamental coding, must be translated to work with a specific CPU (Central Processing Unit).The higher level languages come in two forms: compiled and interpreted. A compiled language is run through a software process that translates the code into machine language; examples are C, C++, and Delphi . Interpreted languages are translated and executed one instruction at a time; examples are Basic, Visual Basic, and Java. A compiled program (after compilation) will run faster than an interpretive one. However, changes in the faster program require re-compilation.

This is an example of Fortran coding.

C PROGRAM TO AVERAGE THREE NUMBERS

C   A, B, AND C DENOTE THE NUMBERS

C   AV DENOTES THE AVERAGE

  A=12.25

  B=19.40

  C=17.10

  AV=(A+B+C)/3.0

  WRITE(6,10)AV

•  FORMAT(1X,'AVERAGE IS' ,F7.2

STOP

END

Would produce AVERAGE IS 16.25

The C prefix stands for Comment, a non-executable statement used for documentation. In this instance, you would have to rewrite the program to revalue the 3 constants and then recompile the program to run it – not very practical. Of course, there are ways to input fresh data without reinventing the wheel. That is beyond the scope of this article.

The following examples of programming in BASIC are intentionally trivial. We just wish to show the mechanics of how to use the application in Windows OS's. The instruction code can be written in Notepad, the simple word processor included with the Operating System. This demonstrates batch files , and uses the filename extension of .BAT. They function in the MS-DOS (Microsoft-Disk Operating System)environment; in Win XP, you get there via Start | All Programs | Accessories | Command Prompt. The first command you should enter in the MS-DOS environment is DOSKEY . This utility will keep a list of the commands entered for that session. Recalling a command is done by the arrow keys; a mouse does not work in DOS. To get ‘Full Screen' in DOS, use <Alt> <Enter> key combination.

The following BASIC program takes a list of words as an argument and outputs them as a single word per line.

@ECHO OFF

REM This is SHOWPRM3.BAT

IF %1!==! GOTO OOPS

:TOP

IF %1!==! GOTO END

ECHO %1

SHIFT

GOTO TOP

:OOPS

ECHO Enter several words after %0

:END

The % character is a placeholder for up to 9 items. The @, preceding the ECHO OFF command, prevents that command from being displayed. REM stands for Remark and is not an executable instruction; it is used to document the program. The colon before a term makes it a label . Labels and variables are not case sensitive, but values are; alpha = a and ALPHA = a give the same result; however, alpha = a and alpha = A are NOT equivalent.

Usage: SHOWPRM3.BAT alpha beta gamma delta

Yields: alpha

  beta

  gamma

  delta

This batch program deletes backup files named with the extension .bak. The asterisk, *, is a wild card for any number of characters.

@ECHO OFF

REM This is BAK.BAT

IF NOT EXIST *.BAK GOTO OOPS

DEL *.BAK

ECHO *BAK files deleted

GOTO END

:OOPS

ECHO No *.BAK files found

:END

To see a list of COMMANDS for BASIC, type HELP |more. The switch “|more” pauses the display at a full screen. Without it the display will roll to the last screen and you will not be able to see the beginning of the list. To view the rest of the list, type p (for page) ® Lines: ; enter the number of lines to view next. <CTRL> C is the “ESC” equivalent.

The following Website could get you started in learning more about the BASIC programming language.

http://en.wikipedia.org/wiki/BASIC_programming_language - Syntax

In the Microsoft world, BASIC and QBasic (Quick Basic) has been supplanted by Visual Basic (VB). A stand-alone product, it sells for ~$200. VBA (Visual Basic for Applications) is included with Microsoft Office applications.

From http://en.wikipedia.org/wiki/Visual_Basic_for_Applications

What Is Visual Basic?

When Microsoft started getting hooked on GUIs (Graphical User Interfaces), with a long series of Basic interpreters and compilers behind them, they created Visual Basic. Distributed in both a DOS and a Windows version, it allowed one to write a GUI with almost no trouble at all. It is called visual because you can create the GUI just using normal drag and drop techniques, see what it looks like as you go and then VB writes the code for you. The DOS version ended with 1.0 (with a professional update) and the Windows version continues to evolve. It went through version 6 before becoming VBNET. The reason Visual Basic is so popular today is because it allows one to very quickly write applications. It manages to be a RAD (Rapid Application Development) environment by hiding all the little details and only exposing the parts that are most important to us.

Programming languages are a subset of computer languages. HTML (Hyper Text Markup Language), for example, is a markup language – not a programming language – but is still a computer language. Another example is SQL (Structured Query Language) for accessing relational databases. As a Novice SIG topic, we will be concerned with the more popular entities.

The following is courtesy of www.sharpened.net/glossary :

C is a high-level programming language that was developed in the mid-1970s. It was originally used for writing UNIX programs, but now is used to write applications for nearly every available platform. Some nice things about the language are that it is easy to read, it is flexible (can be used for a wide variety of purposes), and C programs typically use memory very efficiently.

C++ , pronounced "C plus plus," is a programming language that was built off the C language. The syntax of C++ is nearly identical to C, but it has object-oriented features, which allow the programmer to create objects within the code. This makes programming easier, more efficient, and some would even say more fun. Because of the power and flexibility of the language, most programs today are written in C++.

Java is Sun's trademark for a set of technologies for creating and safely running software programs in both stand-alone and networked environments. There was quite a hubbub between Microsoft and Sun over Java code when Microsoft tried to modify it and include it in Windows. For an exhaustive article on Java, see www.stanford.edu/class/cs193i/handouts2003/JavaSection.pdf .

JavaBeans - reusable software modules that are written in the Java programming language. These modules can be deployed in a network or within individual applications, such as Web browsers and word processors, on any major operating system. Like Java applets, JavaBeans can be used to give Web pages interactive capabilities.

JavaScript  - a scripting language developed by Netscape that allows programmers to create interactive elements and dynamic content for Web pages. Widely supported by Microsoft and Netscape browsers and other Web tools, JavaScript code is embedded in HTML pages. JavaScript was initially based on Sun Microsystems's Java, and it shares many of the features and structures of that programming language.

JIT  - just-in-time compiler – a code generator that converts Java byte code into machine code designed to run on specific computer hardware, just before the Java program is run. Although a JIT works much like a Java Virtual Machine (JVM), it does its job more quickly. Java programs often run faster with a JIT than with a JVM. Under Internet Options ® Advanced tab ® Microsoft VM section, you will find a checkbox to toggle the JIT compiler.

The following is from www.python.org/

Python ® is a dynamic object-oriented programming language that can be used for many kinds of software development. It offers strong support for integration with other languages and tools, comes with extensive standard libraries, and can be learned in a few days. Many Python programmers report substantial productivity gains and feel the language encourages the development of higher quality, more maintainable code.

Python is absolutely free, even for commercial use (including resale). You can sell a product written in Python or a product that embeds the Python interpreter. No licensing fees need to be paid for such usage.

PHP - Stands for "Hypertext Preprocessor." PHP is an HTML-embedded Web scripting language. This means PHP code can be inserted into the HTML of a Web page. When a PHP page is accessed, the PHP code is read or "parsed" by the server the page resides on. The outputs from the PHP functions on the page are typically returned as HTML code, which can be read by the browser. Because the PHP code is transformed into HTML before the page is loaded, users cannot view the PHP code on a page. This makes PHP pages secure enough to access databases and other secure information.

A lot of the syntax of PHP is borrowed from other languages such as C, Java and Perl. However, PHP has a number of unique features and specific functions as well. The goal of the language is to allow Web developers to write dynamically generated pages quickly and easily. PHP is also great for creating database-driven Web sites. If you would like to learn more about PHP, the official site is PHP.net.

PERL - Perl stands for "Practical Extraction and Report Language," but you don't really need to know that unless you want to impress your nerd friends. Perl is a scripting language which uses syntax similar to C/C++. It is commonly used by Web programmers to create scripts for Web servers. Perl is especially good at parsing text, so programmers often use it for reading and searching through text files.

As a regular computer user, you won't get to see Perl in action, since it does most of its work "behind the scenes." Perl scripts are run on the server computer before any information is sent to your Web browser. Oh well, the code looks like hieroglyphics to most people anyway.

API - Although not strictly a programming language, API ( Application Programming Interface)   is the specification defining how an application accesses the functionality of an operating environment or another application. Programmers developing Windows applications, for example, write to Windows APIs, which provide access to such user interface elements as scroll bars or icons as well as messaging, printing, and display functions. An example is:

The OpenGL® API began as an initiative by SGI (Silicon Graphics) to create a single, vendor-independent API for the development of 2D and 3D graphics applications. Prior to the introduction of OpenGL, many hardware vendors had different graphics libraries. This situation made it expensive for software developers to support versions of their applications on multiple hardware platforms, and it made porting of applications from one hardware platform to another very time-consuming and difficult. SGI saw the lack of a standard graphics API as an inhibitor to the growth of the 3D marketplace and decided to lead an industry group in creating such a standard.

Glosses and acronyms tend to be intimidating but are a real part of the shorthand jargon for the computer cognoscenti. Tossed about as literary barbs, they can quickly alienate true seekers of information. The lengths to which some go to create acronyms can be a little far-reaching. Consider the following:

AJAX  ( Asynchronous JavaScript and XML).

By invoking the name of a mythical Greek hero and adding the superfluous term Asynchronous, we are led to believe this is a good thing. An alias for AJAX is IPU (In-place Page Updating), not quite as catchy.