<!DOCTYPE html><html><body><title>Euphoria Programming Language Tutorial</title>

<h1>Euphoria Programming Language Tutorial</h1>

<p>This tutorial gives you basic understanding of Euphoria programming language. Euphoria is simple, flexible, easy to learn, and interpreted high-level programming language for DOS, Windows, Linux, FreeBSD, and more. This tutorial describes everything a programmer needs to know such as its environment, data types, syntax and operators, file handling, and controlling the flow of program.</p>

<h1>Audience</h1>

<p>This tutorial is designed for the aspiring students who are keen to learn and understand Euphoria in detail. This tutorial would be of great help for the IT professionals working as programmers. The enthusiastic readers can access this tutorial as a source of additional reading.</p>

<h1>Prerequisites</h1>

<p>Before proceeding with this tutorial, you need to have a basic knowledge of working on Windows or Linux. You need to be familiar with any programming language such as C, C++. You need to have sound understanding of operating system, memory allocation and de-allocation, and basics of efficient programming and debugging.</p>

<p>&copy; Copyright 2017. All Rights Reserved.</p>

<title>Euphoria Overview</title>

<h1>Euphoria - Overview</h1>

<p>Euphoria stands for <b>E</b>nd-<b>U</b>ser <b>P</b>rogramming with <b>H</b>ierarchical <b>O</b>bjects for <b>R</b>obust <b>I</b>nterpreted <b>A</b>pplications. Euphoria's first incarnation was created by Robert Craig on an Atari Mega-ST and it was first released in 1993. It is now maintained by Rapid Deployment Software.</p>

<p>It is a free, simple, flexible, easy to learn, and interpreted but extremely fast 32-bit high-level programming language for DOS, Windows, Linux, FreeBSD and more.</p>

<p>Euphoria is being used to develop Windows GUI programs, high-speed DOS games, and Linux/FreeBSD X Windows programs. Euphoria can also be used for CGI (Webbased) programming.</p>

<h2>Euphoria Features</h2>

<p>Here is the list of major features of Euphoria &minus;</p>

<p>It is a simple, flexible, powerful language definition that is easy to learn and use.</p>

<p>It supports dynamic storage allocation which means variables grow or shrink without the programmer having to worry about allocating and freeing the memory. It takes care of garbage collection automatically.</p>

<p>It is extremely faster than conventional interpreters such as Perl and Python.</p>

<p>Euphoria programs run under Linux, FreeBSD, 32-bit Windows, and any DOS environment.</p>

<p>Euphoria programs are not subject to any 640K memory limitations.</p>

<p>It provides an optimizing Euphoria-To-C translator which you can use to translate your Euphoria program into C and then compile it with a C compiler to get an executable (.exe) file. This can boost your program speed by 2 to 5 times.</p>

<p>Underlying hardware are completely hidden which means programs are not aware of word-lengths, underlying bit-level representation of values, byte-order etc.</p>

<p>Euphoria installation comes along with a full-screen source debugger, an execution profiler, and a full-screen multi-file editor.</p>

<p>It supports run-time error-handling, subscript, and type checking.</p>

<p>It is an open source language and comes completely free of cost.</p>

<h2>Platform Requirements</h2>

<p>Euphoria is available on Windows, Linux, FreeBSD, and OSX. Here is the bare minimum version required with the following platforms &minus;</p>

<p><b>WIN32 version</b> &minus; You need Windows 95 or any later version of Windows. It runs fine on XP and Vista.</p>

<p><b>Linux version</b> &minus; You need any reasonably up-to-date Linux distribution, that has libc6 or later. For example, Red Hat 5.2 or later works fine.</p>

<p><b>FreeBSD version</b> &minus; You need any reasonably up-to-date FreeBSD distribution.</p>

<p><b>Mac OS X version</b> &minus; You need any reasonably up-to-date Intel based Mac.</p>

<h2>Euphoria Limitations</h2>

<p>Here are some prominent limitations of Euphoria &minus;</p>

<p>Even though Euphoria is simple, fast, and flexible enough for the programmers; it does not provide call support for many important functionalities. For example, network programming.</p>

<p>Euphoria was invented in 1993, and still you would not find any book written on this language. There is also not much documentation available for the language.</p>

<p>But these days, the language is getting popular very fast and you can hope to have nice utilities and books available for the language very soon.</p>

<h2>Euphoria Licensing</h2>

<p>This product is free and open source, and has benefited from the contributions of many people. You have complete royalty-free rights to distribute any Euphoria programs that you develop.</p>

<p>Icon files, such as euphoria.ico and binaries available in euphoria\bin, may be distributed with or without your changes.</p>

<p>You can <b>shroud</b> or <b>bind</b> your program and distribute the resulting files royalty-free. Some additional 3^rd party legal restrictions might apply when you use the Euphoria- To-C translator.</p>

<p>&copy; Copyright 2017. All Rights Reserved.</p>

<title>Euphoria Environment</title>

<h1>Euphoria - Environment</h1>

<p>This chapter describes about the installation of Euphoria on various platforms. You can follow the steps to install Euphoria on Linux, FreeBSD, and 32-bit Windows. So you can choose the steps based on your working environment.</p>

<h2>Linux, Free BSD Installation</h2>

<p>Official website provides <b>.tar.gz</b> file to install Euphoria on your Linux or BSD OS. You can download your latest version of Euphoria from its official website &minus; <a rel="nofollow" href="http://www.rapideuphoria.com/" target="_blank">Download Euphoria</a>.</p>

<p>Once you have .tar.gz file, here are three simple steps to be performed to install Euphoria on your Linux or Free BSD machine &minus;</p>

<p><b>Step 1</b> &minus; Installing Files</p>

<p>Untar the downloaded file <b>euphoria-4.0b2.tar.gz</b> in a directory where you want to install Euphoria. If you want to install it in /home directory as follows, then &minus;</p>

<p>This creates a directory hierarchy inside <b>/home/euphoria-4.0b2</b> directory as follows &minus;</p>

<p><b>NOTE</b> &minus; File name euphoria-4.0b2.tar.gz depends on latest version available. We are using 4.0b2 version of the language for this tutorial.</p>

<p><b>Step 2</b> &minus; Setting Up the Path</p>

<p>After installing Euphoria, you need to set proper paths so that your shell can find required Euphoria binaries and utilities. Before proceeding, there are following three important environment variables you need to set up &minus;</p>

<p>Set PATH environment variable to point /home/euphoria-4.0b2/bin directory.</p>

<p>Set EUDIR environment variable to point to /home/euphoria-4.0b2.</p>

<p>Set EUINC environment variable to point to /home/euphoria-4.0b2/include.</p>

<p>These variables can be set as follows &minus;</p>

<p><b>NOTE</b> &minus; The above commands used to set environment variables may differ depending on your Shell. We used <i>bash</i> shell for executing these commands to set the variables.</p>

<p><b>Step 3</b> &minus; Confirmation Installation</p>

<p>Confirm if you installed Euphoria successfully or not.</p>

<p>Execute the following command &minus;</p>

<p>If you get following result, then it means you have installed Euphoria successfully; otherwise you have to go back and check all the steps again.</p>

<p>That is it, Euphoria Programming Environment is ready on your UNIX machine, and you can start writing complex programs in easy steps.</p>

<h2>WIN32, and DOS Installation</h2>

<p>Official website provides <b>.exe</b> file to install Euphoria on your WIN32 or DOS OS. You can download your latest version of Euphoria from its official website &minus; <a href="http://www.rapideuphoria.com/" rel="nofollow" target="_blank">Download Euphoria</a>.</p>

<p>Once you have .exe file, here are three simple steps to follow for installing Euphoria Programming language on your WIN32 or DOS machine &minus;</p>

<p><b>Step 1</b> &minus; Installing Files</p>

<p>Double click on the downloaded <b>.exe</b> setup program to install all the files. We downloaded euphoria-40b2.exe file for installation.</p>

<p>The filename euphoria-40b2.exe depends on latest version available. We use version 4 beta 2 of the language.</p>

<p>By default Euphoria would be installed in C:\<i>euphoria-40b2</i> directory but you can also select a desired location.</p>

<p><b>Step 2</b> &minus; Rebooting the Machine</p>

<p>Re-boot your machine to complete the installation.</p>

<p><b>Step 3</b> &minus; Confirmation Installation</p>

<p>Confirm if you installed Euphoria successfully or not.</p>

<p>Execute the following command &minus;</p>

<p>If you get following result, then it means you have installed Euphoria successfully; otherwise you have to go back and check all the steps again.</p>

<p>That is it, Euphoria Programming Environment is ready on your WIN32 machine, and you can start writing complex programs in easy steps.</p>

<h2>Euphoria Interpreters</h2>

<p>Depending on the platform you are using, Euphoria has multiple interpreters &minus;</p>

<p>The main interpreter is <b>eui</b>.</p>

<p>On windows platforms, you have two choices. If you run <b>eui</b> then a console window is created. If you run <b>euiw</b> then no console is created, making it suitable for GUI applications.</p>

<p>Euphoria does not care about your choice of file extensions. By convention however; the console-based applications come with <b>.ex</b> extension.</p>

<p>GUI-based applications have <b>.exw</b> extension and the include files have <b>.e</b> extension.</p>

<p>&copy; Copyright 2017. All Rights Reserved.</p>

<pre class="result notranslate">

$cp euphoria-4.0b2.tar.gz /home

$cd /home

$gunzip euphoria-4.0b2.tar.gz

$tar -xvf euphoria-4.0b2.tar

<p>This creates a directory hierarchy inside <b>/home/euphoria-4.0b2</b> directory as follows &minus;</p>

<pre class="result notranslate">

$ls -l

-rw-r--r-- 1 1001 1001 2485 Aug 17 06:15 Jamfile

-rw-r--r-- 1 1001 1001 5172 Aug 20 12:37 Jamrules

-rw-r--r-- 1 1001 1001 1185 Aug 13 06:21 License.txt

drwxr-xr-x 2 1001 1001 4096 Aug 31 10:07 bin

drwxr-xr-x 7 1001 1001 4096 Aug 31 10:07 demo

-rw-r--r-- 1 1001 1001 366 Mar 18 09:02 file_id.diz

drwxr-xr-x 4 1001 1001 4096 Aug 31 10:07 include

-rw-r--r-- 1 1001 1001 1161 Mar 18 09:02 installu.doc

drwxr-xr-x 4 1001 1001 4096 Aug 31 10:07 source

drwxr-xr-x 19 1001 1001 4096 Sep 7 12:09 tests

drwxr-xr-x 2 1001 1001 4096 Aug 31 10:07 tutorial

<p><b>NOTE</b> &minus; File name euphoria-4.0b2.tar.gz depends on latest version available. We are using 4.0b2 version of the language for this tutorial.</p>

<p><b>Step 2</b> &minus; Setting Up the Path</p>

<p>After installing Euphoria, you need to set proper paths so that your shell can find required Euphoria binaries and utilities. Before proceeding, there are following three important environment variables you need to set up &minus;</p>

<ul class="list">

<li><p>Set PATH environment variable to point /home/euphoria-4.0b2/bin directory.</p></li>

<li><p>Set EUDIR environment variable to point to /home/euphoria-4.0b2.</p></li>

<li><p>Set EUINC environment variable to point to /home/euphoria-4.0b2/include.</p></li>

<p>These variables can be set as follows &minus;</p>

<pre class="result notranslate">

$export PATH=$PATH:/home/euphoria-4.0b2/bin

$export EUDIR=/home/euphoria-4.0b2

$export EUINC=/home/euphoria-4.0b2/include

<p><b>NOTE</b> &minus; The above commands used to set environment variables may differ depending on your Shell. We used <i>bash</i> shell for executing these commands to set the variables.</p>

<p><b>Step 3</b> &minus; Confirmation Installation</p>

<p>Confirm if you installed Euphoria successfully or not.</p>

<p>Execute the following command &minus;</p>

<pre class="result notranslate">

$eui -version

<p>If you get following result, then it means you have installed Euphoria successfully; otherwise you have to go back and check all the steps again.</p>

<pre class="result notranslate">

$eui -version

Euphoria Interpreter 4.0.0 beta 2 (r2670) for Linux

Using System Memory

$

<p>That is it, Euphoria Programming Environment is ready on your UNIX machine, and you can start writing complex programs in easy steps.</p>

<h2>WIN32, and DOS Installation</h2>

<p>Official website provides <b>.exe</b> file to install Euphoria on your WIN32 or DOS OS. You can download your latest version of Euphoria from its official website &minus; <a href="http://www.rapideuphoria.com/" rel="nofollow" target="_blank">Download Euphoria</a>.</p>

<p>Once you have .exe file, here are three simple steps to follow for installing Euphoria Programming language on your WIN32 or DOS machine &minus;</p>

<p><b>Step 1</b> &minus; Installing Files</p>

<p>Double click on the downloaded <b>.exe</b> setup program to install all the files. We downloaded euphoria-40b2.exe file for installation.</p>

<p>The filename euphoria-40b2.exe depends on latest version available. We use version 4 beta 2 of the language.</p>

<p>By default Euphoria would be installed in C:\<i>euphoria-40b2</i> directory but you can also select a desired location.</p>

<p><b>Step 2</b> &minus; Rebooting the Machine</p>

<p>Re-boot your machine to complete the installation.</p>

<p><b>Step 3</b> &minus; Confirmation Installation</p>

<p>Confirm if you installed Euphoria successfully or not.</p>

<p>Execute the following command &minus;</p>

<pre class="result notranslate">

c:\&gt;eui -version

<p>If you get following result, then it means you have installed Euphoria successfully; otherwise you have to go back and check all the steps again.</p>

<pre class="result notranslate">

c:\&gt;eui -version

Euphoria Interpreter 4.0.0 beta 2 (r2670) for Windows

Using Managed Memory

c:\&gt;

<title>Euphoria Basic Syntax</title>

<h1>Euphoria - Basic Syntax</h1>

<p>The Euphoria language has many similarities to Perl, C, and Java. However, there are some definite differences between the languages. This chapter is designed to quickly get you up to speed on the syntax that is expected in Euphoria.</p>

<p>This tutorial assumes you are working with Linux and all the examples have been written on Linux platform. But it is observed that there is no any prominent difference in program syntax on Linux and WIN32. Hence you can follow the same steps on WIN32.</p>

<h2>First Euphoria Program</h2>

<p>Let us write a simple Euphoria program in a script. Type the following source code in test.ex file and save it.</p>

<p>Let us say, Euphoria interpreter is available in <i>/home/euphoria-4.0b2/bin/</i> directory. Now run this program as follows &minus;</p>

<p>This produces the following result &minus;</p>

<p>This script used a built-in function <b>puts()</b> which takes two arguments. First argument indicates file name or device number, and second argument indicates a string which you want to print. Here 1 indicates STDOUT device.</p>

<h2>Euphoria Identifiers</h2>

<p>A Euphoria identifier is a name used to identify a variable, function, class, module, or other object. An identifier starts with a letter A to Z or a to z and then followed by letters, digits, or underscores.</p>

<p>Euphoria does not allow punctuation characters such as @, $, and % within identifiers.</p>

<p>Euphoria is a case sensitive programming language. Thus <b>Manpower</b> and <b>manpower</b> are two different identifiers in Euphoria. For example, the valid identifiers are &minus;</p>

<h2>Reserved Words</h2>

<p>The following list shows the reserved words in Euphoria. These reserved words may not be used as constant or variable or any other identifier names. Euphoria keywords contain lowercase letters only.</p>

<h2>Expressions</h2>

<p>Euphoria lets you calculate results by forming expressions. However, in Euphoria you can perform calculations on entire sequences of data with one expression.</p>

<p>You can handle a sequence much as you would handle a single number. It can be copied, passed to a subroutine, or calculated upon as a unit. For example &minus;</p>

<p>This is an expression that adds the sequence {1, 2, 3} and the atom 5 to get the resulting sequence {6, 7, 8}. You would learn sequences in subsequent chapters.</p>

<h2>Blocks of code</h2>

<p>One of the first caveats programmers encounter when learning Euphoria is the fact that there are no braces to indicate blocks of code for procedure and function definitions or flow control. Blocks of code are denoted by associated keywords.</p>

<p>The following example shows <b>if...then...end if</b> block &minus;</p>

<h2>Multi-Line Statements</h2>

<p>Statements in Euphoria typically end with a new line. Euphoria does however, allow to write a single statement in multiple lines. For example &minus;</p>

<h2>Escape Characters</h2>

<p>Escape characters may be entered using a back-slash. For example &minus;</p>

<p>The following table is a list of escape or non-printable characters that can be represented with backslash notation.</p>

<h2>Comments in Euphoria</h2>

<p>Any comments are ignored by the compiler and have no effect on execution speed. It is advisable to use more comments in your program to make it more readable.</p>

<p>There are three forms of comment text &minus;</p>

<p>Comments start by two dashes and extend to the end of the current line.</p>

<p>The multi-line format comment is kept inside /*...*/, even if that occurs on a different line.</p>

<p>You can use a special comment beginning with the two character sequence “#!” only on the first line of the program.</p>

<h3>Examples</h3>

<p>This produces the following result &minus;</p>

<p><b>Note</b> &minus; You can use a special comment beginning with “#!”. This informs the Linux shell that your file should be executed by the Euphoria interpreter.</p>

<p>&copy; Copyright 2017. All Rights Reserved.</p>

<pre class="prettyprint notranslate">

#!/home/euphoria-4.0b2/bin/eui

puts(1, "Hello, Euphoria!\n")

<p>Let us say, Euphoria interpreter is available in <i>/home/euphoria-4.0b2/bin/</i> directory. Now run this program as follows &minus;</p>

<pre class="prettyprint notranslate">

$ chmod +x test.ex # This is to make file executable

$ ./test.ex

<p>This produces the following result &minus;</p>

<pre class="result notranslate">

Hello, Euphoria!

<p>This script used a built-in function <b>puts()</b> which takes two arguments. First argument indicates file name or device number, and second argument indicates a string which you want to print. Here 1 indicates STDOUT device.</p>

<h2>Euphoria Identifiers</h2>

<p>A Euphoria identifier is a name used to identify a variable, function, class, module, or other object. An identifier starts with a letter A to Z or a to z and then followed by letters, digits, or underscores.</p>

<p>Euphoria does not allow punctuation characters such as @, $, and % within identifiers.</p>

<p>Euphoria is a case sensitive programming language. Thus <b>Manpower</b> and <b>manpower</b> are two different identifiers in Euphoria. For example, the valid identifiers are &minus;</p>

<ul class="list">

<li>n</li>

<li>color26</li>

<li>ShellSort</li>

<li>quick_sort</li>

<li>a_very_long_indentifier</li>

<h2>Reserved Words</h2>

<p>The following list shows the reserved words in Euphoria. These reserved words may not be used as constant or variable or any other identifier names. Euphoria keywords contain lowercase letters only.</p>

<table class="table table-bordered">

<td>and</td>

<td>exit</td>

<td>override</td>

<td>as</td>

<td>export</td>

<td>procedure</td>

<td>break</td>

<td>fallthru</td>

<td>public</td>

<td>by</td>

<td>for</td>

<td>retry</td>

<td>case</td>

<td>function</td>

<td>return</td>

<td>constant</td>

<td>global</td>

<td>routine</td>

<td>continue</td>

<td>goto</td>

<td>switch</td>

<td>do</td>

<td>if</td>

<td>then</td>

<td>else</td>

<td>ifdef</td>

<td>to</td>

<td>elsedef</td>

<td>include</td>

<td>type</td>

<td>elsif</td>

<td>label</td>

<td>until</td>

<td>elsifdef</td>

<td>loop</td>

<td>while</td>

<td>end</td>

<td>namespace</td>

<td>with</td>

<td>entry</td>

<td>not</td>

<td>without</td>

<td>enum</td>

<td>or</td>

<td>xor</td>

<h2>Expressions</h2>

<p>Euphoria lets you calculate results by forming expressions. However, in Euphoria you can perform calculations on entire sequences of data with one expression.</p>

<p>You can handle a sequence much as you would handle a single number. It can be copied, passed to a subroutine, or calculated upon as a unit. For example &minus;</p>

<pre class="result notranslate">

{1,2,3} + 5

<p>This is an expression that adds the sequence {1, 2, 3} and the atom 5 to get the resulting sequence {6, 7, 8}. You would learn sequences in subsequent chapters.</p>

<h2>Blocks of code</h2>

<p>One of the first caveats programmers encounter when learning Euphoria is the fact that there are no braces to indicate blocks of code for procedure and function definitions or flow control. Blocks of code are denoted by associated keywords.</p>

<p>The following example shows <b>if...then...end if</b> block &minus;</p>

<pre class="prettyprint notranslate">

if condition then

code block comes here

end if

<h2>Multi-Line Statements</h2>

<p>Statements in Euphoria typically end with a new line. Euphoria does however, allow to write a single statement in multiple lines. For example &minus;</p>

<pre class="prettyprint notranslate">

total = item_one +

item_two +

item_three

<h2>Escape Characters</h2>

<p>Escape characters may be entered using a back-slash. For example &minus;</p>

<p>The following table is a list of escape or non-printable characters that can be represented with backslash notation.</p>

<table style="text-align:center;" class="table table-bordered">

<th style="text-align:center;">Backslash notation</th>

<th style="text-align:center;">Description</th>

<td>\n</td>

<td>Newline</td>

<td>\r</td>

<td>Carriage return</td>

<td>\t</td>

<td>Tab</td>

<td>\\</td>

<td>Backslash</td>

<td>\"</td>

<td>Double quote</td>

<td>\'</td>

<td>Single quote</td>

<h2>Comments in Euphoria</h2>

<p>Any comments are ignored by the compiler and have no effect on execution speed. It is advisable to use more comments in your program to make it more readable.</p>

<p>There are three forms of comment text &minus;</p>

<ul class="list">

<li><p>Comments start by two dashes and extend to the end of the current line.</p></li>

<li><p>The multi-line format comment is kept inside /*...*/, even if that occurs on a different line.</p></li>

<li><p>You can use a special comment beginning with the two character sequence “#!” only on the first line of the program.</p></li>

<h3>Examples</h3>

<pre class="prettyprint notranslate">

#!/home/euphoria-4.0b2/bin/eui

-- First comment

puts(1, "Hello, Euphoria!\n") -- second comment

/* This is a comment which extends over a number

of text lines and has no impact on the program

*/

<p>This produces the following result &minus;</p>

<pre class="result notranslate">

Hello, Euphoria!

<title>Euphoria Variables</title>

<h1>Euphoria - Variables</h1>

<p>Variables are nothing but reserved memory locations to store values. This means when you create a variable, you reserve some space in memory.</p>

<p>Based on the data type of a variable, the interpreter allocates memory and decides what can be stored in the reserved memory. Therefore, by assigning different data types to variables, you can store integers, decimals, or characters in these variables. Euphoria data types are explained in different chapter.</p>

<p>These memory locations are called variables because their value can be changed during their life time.</p>

<h2>Variable Declaration</h2>

<p>Euphoria variables have to be explicitly declared to reserve memory space. Thus declaration of a variable is mandatory before you assign a value to a variable.</p>

<p>Variable declarations have a type name followed by a list of the variables being declared. For example &minus;</p>

<p>When you declare a variable, you name the variable and you define which sort of values may legally be assigned to the variable during execution of your program.</p>

<p>The simple act of declaring a variable does not assign any value to it. If you attempt to read it before assigning any value to it, Euphoria will issue a run-time error as <i>"variable xyz has never been assigned a value"</i>.</p>

<h2>Assigning Values</h2>

<p>The equal sign (=) is used to assign values to variables. Variable can be assigned in the following manner &minus;</p>

<p>Variable_Name = Variable_Value</p>

<p>For example &minus;</p>

<p>Here 100, 1000.0 and "John" are the values assigned to <i>counter</i>, <i>miles</i> and <i>name</i> variables, respectively. This program produces the following result &minus;</p>

<p>To guard against forgetting to initialize a variable, and also because it may make the code clearer to read, you can combine declaration and assignment &minus;</p>

<p>This is equivalent to the following &minus;</p>

<h2>Identifier Scope</h2>

<p>The scope of an identifier is a description of what code can access it. Code in the same scope of an identifier can access that identifier and code not in the same scope as identifier cannot access it.</p>

<p>The scope of a variable depends upon where and how it is declared.</p>

<p>If it is declared within a <b>for, while, loop</b> or <b>switch</b>, its scope starts at the declaration and ends at the respective <b>end</b> statement.</p>

<p>In an <b>if</b> statement, the scope starts at the declaration and ends either at the next <b>else, elsif</b> or <b>end if</b> statement.</p>

<p>If a variable is declared within a routine, the scope of the variable starts at the declaration and ends at the routine's end statement. This is knows as a private variable.</p>

<p>If a variable is declared outside of a routine, its scope starts at the declaration and ends and the end of the file it is declared in. This is known as a module variable.</p>

<p>The scope of a <b>constant</b> that does not have a scope modifier, starts at the declaration and ends and the end of the file it is declared in.</p>

<p>The scope of a <b>enum</b> that does not have a scope modifier, starts at the declaration and ends and the end of the file it is declared in.</p>

<p>The scope of all <b>procedures, functions</b> and <b>types</b>, which do not have a scope modifier, starts at the beginning of the source file and ends at the end of the source file in which they are declared.</p>

<p>Constants, enums, module variables, procedures, functions and types, which do not have a scope modifier are referred to as <b>locals</b>. However, these identifiers can have a scope modifier preceding their declaration, which causes their scope to extend beyond the file they are declared in.</p>

<p>If the keyword <b>global</b> precedes the declaration, the scope of these identifiers extends to the whole application. They can be accessed by code anywhere in the application files.</p>

<p>If the keyword <b>public</b> precedes the declaration, the scope extends to any file that explicitly includes the file in which the identifier is declared, or to any file that includes a file that in turn <i>public</i> includes the file containing the <i>public</i> declaration.</p>

<p>If the keyword <b>export</b> precedes the declaration, the scope only extends to any file that directly includes the file in which the identifier is declared.</p>

<p>When you <b>include</b> a Euphoria file in another file, only the identifiers declared using a scope modifier are accessible to the file doing the <i>include</i>. The other declarations in the included file are invisible to the file doing the <i>include</i>.</p>

<p>&copy; Copyright 2017. All Rights Reserved.</p>

<pre class="result notranslate">

integer x, y, z

sequence a, b, x

<p>When you declare a variable, you name the variable and you define which sort of values may legally be assigned to the variable during execution of your program.</p>

<p>The simple act of declaring a variable does not assign any value to it. If you attempt to read it before assigning any value to it, Euphoria will issue a run-time error as <i>"variable xyz has never been assigned a value"</i>.</p>

<h2>Assigning Values</h2>

<p>The equal sign (=) is used to assign values to variables. Variable can be assigned in the following manner &minus;</p>

<p>Variable_Name = Variable_Value</p>

<p>For example &minus;</p>

<pre class="prettyprint notranslate">

#!/home/euphoria/bin/eui

-- Here is the declaration of the variables.

integer counter

integer miles

sequence name

counter = 100 -- An integer assignment

miles = 1000.0 -- A floating point

name = "John" -- A string ( sequence )

printf(1, "Value of counter %d\n", counter )

printf(1, "Value of miles %f\n", miles )

printf(1, "Value of name %s\n", {name} )

<p>Here 100, 1000.0 and "John" are the values assigned to <i>counter</i>, <i>miles</i> and <i>name</i> variables, respectively. This program produces the following result &minus;</p>

<pre class="result notranslate">

Value of counter 100

Value of miles 1000.000000

Value of name John

<p>To guard against forgetting to initialize a variable, and also because it may make the code clearer to read, you can combine declaration and assignment &minus;</p>

<pre class="result notranslate">

integer n = 5

<p>This is equivalent to the following &minus;</p>

<pre class="result notranslate">

integer n

n = 5

<title>Euphoria Constants</title>

<h1>Euphoria - Constants</h1>

<p>Constants are also variables that are assigned an initial value that can never change in the program’s life. Euphoria allows to define constants using constant keyword as follows &minus;</p>

<p>The result of any expression can be assigned to a constant, even one involving calls to previously defined functions, but once the assignment is made, the value of the constant variable is "locked in".</p>

<p>Constants may not be declared inside a subroutine. The scope of a <b>constant</b> that does not have a scope modifier, starts at the declaration and ends and the end of the file it is declared in.</p>

<h3>Examples</h3>

<p>This produces the following error &minus;</p>

<p>If you delete last two lines from the example, then it produces the following result &minus;</p>

<h2>The <i>enums</i></h2>

<p>An enumerated value is a special type of constant where the first value defaults to the number 1 and each item after that is incremented by 1. Enums can only take numeric values.</p>

<p>Enums may not be declared inside a subroutine. The scope of an <b>enum</b> that does not have a scope modifier, starts at the declaration and ends and the end of the file it is declared in.</p>

<h3>Examples</h3>

<p>This will produce following result &minus;</p>

<p>You can change the value of any one item by assigning it a numeric value. Subsequent values are always the previous value plus one, unless they too are assigned a default value.</p>

<p>This produce the following result &minus;</p>

<p>Sequences use integer indices, but with enum you may write code like this &minus;</p>

<p>&copy; Copyright 2017. All Rights Reserved.</p>

<pre class="prettyprint notranslate">

constant MAX = 100

constant Upper = MAX - 10, Lower = 5

constant name_list = {"Fred", "George", "Larry"}

<p>The result of any expression can be assigned to a constant, even one involving calls to previously defined functions, but once the assignment is made, the value of the constant variable is "locked in".</p>

<p>Constants may not be declared inside a subroutine. The scope of a <b>constant</b> that does not have a scope modifier, starts at the declaration and ends and the end of the file it is declared in.</p>

<h3>Examples</h3>

<pre class="prettyprint notranslate">

#!/home/euphoria-4.0b2/bin/eui

constant MAX = 100

constant Upper = MAX - 10, Lower = 5

printf(1, "Value of MAX %d\n", MAX )

printf(1, "Value of Upper %d\n", Upper )

printf(1, "Value of Lower %d\n", Lower )

MAX = MAX + 1

printf(1, "Value of MAX %d\n", MAX )

<p>This produces the following error &minus;</p>

<pre class="result notranslate">

./test.ex:10

&lt;0110&gt;:: may not change the value of a constant

MAX = MAX + 1

^

Press Enter

<p>If you delete last two lines from the example, then it produces the following result &minus;</p>

<pre class="result notranslate">

Value of MAX 100

Value of Upper 90

Value of Lower 5

<h2>The <i>enums</i></h2>

<p>An enumerated value is a special type of constant where the first value defaults to the number 1 and each item after that is incremented by 1. Enums can only take numeric values.</p>

<p>Enums may not be declared inside a subroutine. The scope of an <b>enum</b> that does not have a scope modifier, starts at the declaration and ends and the end of the file it is declared in.</p>

<h3>Examples</h3>

<pre class="prettyprint notranslate">

#!/home/euphoria-4.0b2/bin/eui

enum ONE, TWO, THREE, FOUR

printf(1, "Value of ONE %d\n", ONE )

printf(1, "Value of TWO %d\n", TWO )

printf(1, "Value of THREE %d\n", THREE )

printf(1, "Value of FOUR %d\n", FOUR )

<p>This will produce following result &minus;</p>

<pre class="result notranslate">

Value of ONE 1

Value of TWO 2

Value of THREE 3

Value of FOUR 4

<p>You can change the value of any one item by assigning it a numeric value. Subsequent values are always the previous value plus one, unless they too are assigned a default value.</p>

<pre class="prettyprint notranslate">

#!/home/euphoria-4.0b2/bin/eui

enum ONE, TWO, THREE, ABC=10, XYZ

printf(1, "Value of ONE %d\n", ONE )

printf(1, "Value of TWO %d\n", TWO )

printf(1, "Value of THREE %d\n", THREE )

printf(1, "Value of ABC %d\n", ABC )

printf(1, "Value of XYZ %d\n", XYZ )

<p>This produce the following result &minus;</p>

<pre class="result notranslate">

Value of ONE 1

Value of TWO 2

Value of THREE 3

Value of ABC 10

Value of XYZ 11

<p>Sequences use integer indices, but with enum you may write code like this &minus;</p>

<pre class="prettyprint notranslate">

enum X, Y

sequence point = { 0,0 }

point[X] = 3

point[Y] = 4

<title>Euphoria Data Types</title>

<h1>Euphoria - Data Types</h1>

<p>The data stored in memory can be of many types. For example, a person's age is stored as a numeric value and his or her address is stored as alphanumeric characters.</p>

<p>Euphoria has some standard types that are used to define the operations possible on them and the storage method for each of them.</p>

<p>Euphoria has following four standard data types &minus;</p>

<p>The understanding of atoms and sequences is the key to understanding Euphoria.</p>

<h2>Integers</h2>

<p>Euphoria integer data types store numeric values. They are declared and defined as follows &minus;</p>

<p>The variables declared with type integer must be atoms with <b>integer</b> values from -1073741824 to +1073741823 inclusive. You can perform exact calculations on larger integer values, up to about 15 decimal digits, but declare them as atom, rather than integer.</p>

<h2>Atoms</h2>

<p>All data objects in Euphoria are either atoms or sequences. An atom is a single numeric value. Atoms can have any integer or double-precision floating point value. Euphoria atoms are declared and defined as follows&minus;</p>

<p>The atoms can range from approximately -1e300 to +1e300 with 15 decimal digits of accuracy. An individual character is an <b>atom</b> which must may be entered using single quotes. For example, all the following statements are legal &minus;</p>

<h2>Sequences</h2>

<p>A sequence is a collection of numeric values which can be accessed through their index. All data objects in Euphoria are either atoms or sequences.</p>

<p>Sequence index starts from 1 unlike other programming languages where array index starts from 0. Euphoria sequences are declared and defined as follows &minus;</p>

<p>A character string is just a <b>sequence</b> of characters which may be entered using double quotes. For example, all the following statements are legal &minus;</p>

<p>Character strings may be manipulated and operated upon just like any other sequences. For example, the above string is entirely equivalent to the sequence &minus;</p>

<p>You will learn more about sequence in <a href="/euphoria/euphoria_sequences.htm">Euphoria &minus; Sequences</a>.</p>

<h2>Objects</h2>

<p>This is a super data type in Euphoria which may take on any value including atoms, sequences, or integers. Euphoria objects are declared and defined as follows &minus;</p>

<p>An object may have one of the following values &minus;</p>

<p>a sequence</p>

<p>an atom</p>

<p>an integer</p>

<p>an integer used as a file number</p>

<p>a string sequence, or single-character atom</p>

<p>&copy; Copyright 2017. All Rights Reserved.</p>

<pre class="prettyprint notranslate">

integer var1, var2

var1 = 1

var2 = 100

<p>The variables declared with type integer must be atoms with <b>integer</b> values from -1073741824 to +1073741823 inclusive. You can perform exact calculations on larger integer values, up to about 15 decimal digits, but declare them as atom, rather than integer.</p>

<h2>Atoms</h2>

<p>All data objects in Euphoria are either atoms or sequences. An atom is a single numeric value. Atoms can have any integer or double-precision floating point value. Euphoria atoms are declared and defined as follows&minus;</p>

<pre class="prettyprint notranslate">

atom var1, var2, var3

var1 = 1000

var2 = 198.6121324234

var3 = 'E'

<p>The atoms can range from approximately -1e300 to +1e300 with 15 decimal digits of accuracy. An individual character is an <b>atom</b> which must may be entered using single quotes. For example, all the following statements are legal &minus;</p>

<pre class="result notranslate">

-- Following is equivalent to the atom 66 - the ASCII code for B

char = 'B'

-- Following is equivalent to the sequence {66}

sentence = "B"

<h2>Sequences</h2>

<p>A sequence is a collection of numeric values which can be accessed through their index. All data objects in Euphoria are either atoms or sequences.</p>

<p>Sequence index starts from 1 unlike other programming languages where array index starts from 0. Euphoria sequences are declared and defined as follows &minus;</p>

<pre class="prettyprint notranslate">

sequence var1, var2, var3, var4

var1 = {2, 3, 5, 7, 11, 13, 17, 19}

var2 = {1, 2, {3, 3, 3}, 4, {5, {6}}}

var3 = {{"zara", "ali"}, 52389, 97.25}

var4 = {} -- the 0 element sequence

<p>A character string is just a <b>sequence</b> of characters which may be entered using double quotes. For example, all the following statements are legal &minus;</p>

<pre class="prettyprint notranslate">

word = 'word'

sentence = "ABCDEFG"

<p>Character strings may be manipulated and operated upon just like any other sequences. For example, the above string is entirely equivalent to the sequence &minus;</p>

<pre class="prettyprint notranslate">

sentence = {65, 66, 67, 68, 69, 70, 71}

<p>You will learn more about sequence in <a href="/euphoria/euphoria_sequences.htm">Euphoria &minus; Sequences</a>.</p>

<h2>Objects</h2>

<p>This is a super data type in Euphoria which may take on any value including atoms, sequences, or integers. Euphoria objects are declared and defined as follows &minus;</p>

<pre class="prettyprint notranslate">

object var1, var2, var3

var1 = {2, 3, 5, 7, 11, 13, 17, 19}

var2 = 100

var3 = 'E'

<title>Euphoria Operators</title>

<h1>Euphoria - Operators</h1>

<p>Euphoria provides a rich set of operators to manipulate variables. We can divide all the Euphoria operators into the following groups &minus;</p>

<h2>The Arithmetic Operators</h2>

<p>Arithmetic operators are used in mathematical expressions in the same way that they are used in Algebra. The following table lists the arithmetic operators. Assume integer variable A holds 10 and variable B holds 20 then &minus;</p>

<p><a href="/euphoria/euphoria_arithmatic_operators.htm">Show Examples</a></p>

<h2>The Relational Operators</h2>

<p>There are following relational operators supported by Euphoria language. Assume variable A holds 10 and variable B holds 20 then &minus;</p>

<p><a href="/euphoria/euphoria_relational_operators.htm">Show Examples</a></p>

<h2>The Logical Operators</h2>

<p>The following table lists the logical operators. Assume boolean variables A holds 1 and variable B holds 0 then &minus;</p>

<p><a href="/euphoria/euphoria_logical_operators.htm">Show Examples</a></p>

<p>You can also apply these operators to numbers other than 1 or 0. The convention is: zero means false and non-zero means <i>true</i>.</p>

<h2>The Assignment Operators</h2>

<p>There are following assignment operators supported by Euphoria language &minus;</p>

<p><a href="/euphoria/euphoria_assignment_operators.htm">Show Examples</a></p>

<p><b>Note</b> &minus; The equals symbol '=' used in an assignment statement is not an operator, it is just a part of the syntax.</p>

<h2>Miscellaneous Operators</h2>

<p>There are few other operators supported by Euphoria Language.</p>

<h3>The '&amp;' Operator</h3>

<p>Any two objects may be concatenated using “&amp;” operator. The result is a sequence with a length equal to the sum of the lengths of the concatenated objects.</p>

<p>For example &minus;</p>

<p>This produces the following result &minus;</p>

<h2>Precedence of Euphoria Operators</h2>

<p>Operator precedence determines the grouping of terms in an expression. This affects how an expression is evaluated. Certain operators have higher precedence than others; for example, the multiplication operator has higher precedence than the addition operator.</p>

<p>For example, x = 7 + 3 * 2</p>

<p>Here, x is assigned 13, not 20 because operator * has higher precedence than +.</p>

<p>Hence it first starts with 3*2 and then adds into 7.</p>

<p>Here operators with the highest precedence appear at the top of the table, those with the lowest appear at the bottom. Within an expression, higher precedence operators is evaluated first.</p>

<p>&copy; Copyright 2017. All Rights Reserved.</p>

<pre class="prettyprint notranslate">

#!/home/euphoria-4.0b2/bin/eui

sequence a, b, c

a = {1, 2, 3}

b = {4}

c = {1, 2, 3} &amp; {4}

printf(1, "Value of c[1] %d\n", c[1] )

printf(1, "Value of c[2] %d\n", c[2] )

printf(1, "Value of c[3] %d\n", c[3] )

printf(1, "Value of c[4] %d\n", c[4] )

<p>This produces the following result &minus;</p>

<pre class="result notranslate">

Value of c[1] 1

Value of c[2] 2

Value of c[3] 3

Value of c[4] 4

<title>Euphoria Branching</title>

<h1>Euphoria - Branching</h1>

<p>Branching is the most important aspect of any programming language. While writing your program, you may encounter a situation when you have to take a decision or you have to select one option out of the given many options.</p>

<p>Following diagram shows a simple scenario where a program needs to take one of the two paths based on the given condition.</p>

<p>Euphoria provides following three types of decision making (branching or conditional) statements &minus;</p>

<p><a href="/euphoria/euphoria_if_statement.htm">if statement</a></p>

<p><a href="/euphoria/euphoria_switch_statement.htm">switch statement</a></p>

<p><a href="/euphoria/euphoria_ifdef_statement.htm">ifdef statement</a></p>

<p>Let us see the statements in detail &minus;</p>

<p>&copy; Copyright 2017. All Rights Reserved.</p>

<title>Euphoria Loop Types</title>

<h1>Euphoria - Loop Types</h1>

<p>Looping is yet another most important aspect of any programming language. While writing your program, you may encounter a situation when you have to execute same statement many times and sometime may be infinite number of times.</p>

<p>There are several ways to specify for how long the process should go on, and how to stop or otherwise alter it. An iterative block may be informally called a loop, and each execution of code in a loop is called an iteration of the loop.</p>

<p>The following diagram shows a simple logical flow of a loop &minus;</p>

<p>Euphoria provides following three types of loop statements &minus;</p>

<p><a href="/euphoria/euphoria_while_statement.htm" title="while statement">while statement</a></p>

<p><a href="/euphoria/euphoria_until_statement.htm" title="loop until statement">loop until statement</a></p>

<p><a href="/euphoria/euphoria_for_statement.htm" title="for statement">for statement</a></p>

<p>All the above statements provide you flexibility and ease of use based on different situations. Let us see them in detail one by one &minus;</p>

<p>&copy; Copyright 2017. All Rights Reserved.</p>

<title>Euphoria Flow Control</title>

<h1>Euphoria - Flow Control</h1>

<p>Program execution flow refers to the order in which program statements get executed. By default the statements get executed one after another.</p>

<p>However; many times the order of execution needs to be altered from the default order, to get the task done.</p>

<p>Euphoria has a number of <i>flow</i> control statements that you can use to arrange the execution order of statements.</p>

<h2>The <i>exit</i> statement</h2>

<p>Exiting a loop is done with the keyword <b>exit</b>. This causes flow to immediately leave the current loop and recommence with the first statement after the end of the loop.</p>

<h3>Syntax</h3>

<p>The syntax of an exit statement is as follows &minus;</p>

<p>The <b>exit</b> statement terminates the latest and innermost loop until an optional label name or number is specified.</p>

<p>A special form of <b>exit N</b> is <b>exit 0</b>. This leaves all levels of loop, regardless of the depth. Control continues after the outermost loop block. Likewise, exit -1 exits the second outermost loop, and so on.</p>