A Beginners Guide To Euphoria


Euphoria Programs And The Programming Language

Before any understanding of Euphoria programming is begun, you must first understand what the terms"program" and "programming" mean. A program, simply put, is a series of computer instructions organized in order to complete a given task. For example, this tutorial's task is to teach a newcomer how to program in Euphoria.  It is made up of computer instructions organized in a way so it can carry out that given task. More complex programs may have their primary task broken down into a series of smaller tasks. For example, a spreadsheet program's primary purpose is to organize and calculate numeric data but this is then broken down further into smaller tasks like graphing forecasting, incorporating the computed figures into a report and so  forth. Your very first programs will have very simple tasks, but as you create larger programs, those tasks will become more complex.

To create a program on your computer is referred to as "programming". You may have also heard of the phrase "coding", which is the same as "programming". "Coding" comes from the fact that the instructions that make up a program are sometimes referred to as "program code". It doesn't really matter what terms you use, just as long as you understand what they mean. But exactly what do the individual instructions that make up a program look like? And how do we enter and group program instructions to create a program? Just as all words of our vocabulary make up the English language, a set of all related computer instructions make up a programming language. The one programming language a computer understands is called "binary". It's called binary because the program instructions are made up of two numbers, 1 and 0, like 100101 for example. Binary language is also referred to as "machine language".

Unfortunately, to write a program in this very difficult language is beyond the ability of most people, save for a very chosen few. The very first computers of the 1950's and 1960's could only be maintained by scientists who had a good understanding of machine language. As time went on, more understandable and easy to use programming languages were created. The program instructions of these languages were more English-like in appearance. Perhaps you may have seen or heard of some of them, such as BASIC, COBOL, RPG, ADA, FORTRAN, PASCAL, C and others. Euphoria is the newest form of computer programming language. For your personal interest, Euphoria stands for End  User  Programming with Hierarchical  Objects for  Robust  Interpreted Applications. Quite a mouthful, but as you will soon discover, the name is the only difficult part of the Euphoria programming language to understand.

To create a Euphoria program, you first start up an editor program that lets you enter Euphoria programming instructions, called "statements". Just as if you were writing a letter, you start typing at the top of the editor window, and then proceed downwards. Exactly what you will be typing will be revealed soon. Understand for now you will require an editor program to do this. MS-DOS's EDIT program is satisfactory, or you can use ED, which comes with the Euphoria software. Once you have finished typing your Euphoria program, you can save it to the hard drive or floppy drive as a file with .EX as the extension. But you're not finished just yet. Remember that your computer only understands machine language. It cannot understand Euphoria programming statements. So, it must be converted to machine language.
 
There are two types of programs that can translate Euphoria to machine language. Both do the same thing but they differ in their methods. One is called a compiler. It takes a Euphoria program and creates a machine language program. This machine language replica has the same name as your Euphoria program, but has a different file extension of .EXE. The other type of translator program is called an interpreter. It translates each Euphoria program statement to a machine language instruction, which is then run. This differs from a compiler, which creates the entire program to be run. Euphoria both comes with a compiler (BIND.BAT) and an interpreter (EX.EXE).  
To run a program using EX.EXE, you type:

                EX filename.EX

To create an executable using BIND.BAT, you type:

                BIND filename.EX

When the executable is created, type:

                filename

The Euphoria program that BIND.BAT will translate into a machine language program is called a "source file". The machine language program is called an "object file". EX.EXE generates "object code". Sometimes it may not be possible to successfully translate your Euphoria program to machine language. While entering Euphoria statements, it is possible you may misspell a word. Just as we have spelling and grammar rules in the written language, Euphoria also demands we follow set rules when typing in these statements. When a spelling or grammar type error is made during the typing in of these statements, it's referred to as a "syntax error". When your compiler encounters this error in your program while trying to translate it to machine language, it will stop. You will then see a message explaining what the error is, and where it is in your Euphoria program. You then start up your editor, correct the statement in error and try to run the compiler or interpreter again.

All programs, no matter what purpose each serves, perform one function. They all process data. This processing of data is broken down into the following three stages listed below:
  1. A program will accept data. The data will consist of numeric figures from either an external source (a keyboard, mouse, digital camera,or voice card) or from somewhere inside the computer (such as a file on a CD-ROM, floppy diskette, or your hard drive).
  2. A program will analyze the accepted data. This step involves temporarily storing the data for both arithmetic calculations and comparison against predefined values, and then making a decision based on the result of the calculation or comparison.
  3. A program will present data in a meaningful form. This means either displaying figures on the screen or printer, storing information on the hard or floppy drive for another program to use later, or creating graphics and sound from the computer that has a meaning to the person running the program.
  No doubt all of this has you eager to start learning how to write your own Euphoria programs. Well, let's get started on learning the actual concepts and instruction statements of the Euphoria programming language!

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