haXe 2 Beginner's Guide

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By Benjamin Dasnois
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  1. Getting to know haXe

About this book

haXe is the universal programming language that is completely cross-platform and provides a standard library that remains the same – regardless of platform.

haXe 2 Beginner's Guide will get you up and running with this exciting language and will guide you through its features in the easiest way possible.

haXe has filled the gap in creating multi-platform applications, and haXe 2 Beginner's Guide will fill the gap in learning all you need to know about haXe – even if it's the first time you have heard of it.

This book will enable you to fully realize haXe's potential for translating code from a haXe program into different languages.

Start with learning how to install haXe, work your way up to templating, and finally learn exactly how to make the same code work for multiple platforms. In between, find heaps of tricks and techniques and work with haXe's typing system. Learn about inheritance, go from learning what a parameter is to creating your own parameterized classes, and find out what the fuss is all about regarding the dynamic type.

By the time you are done with this book, you'll find yourself writing efficient haXe code for multiple platforms in less time than you can say "compatible".

Publication date:
July 2011
Publisher
Packt
Pages
288
ISBN
9781849512565

 

Chapter 1. Getting to know haXe

Entering the haXe World.

In this chapter you will discover haXe's world and enter it. You'll install haXe and write your first program.

This is our first chapter and you will soon be taking your first steps with haXe. However, before you get into action, let's introduce you to haXe and set up your working environment.

In this chapter, you will:

  • Install haXe

  • Choose a code editor based on our requirements

  • Write and run your first program

  • Write a program interacting with the user

Seems like a long list? Don't be afraid, you will make it!

 

Installing haXe


Enough talking, let's install haXe! You will see how easy it is.

Two ways to install: The installer and sources compilation

You should know that there are two ways to install haXe, which are as follows:

  1. Using the installer: An executable that will automatically install haXe for you.

  2. Compiling from sources using the code repository located at the following URL:

    http://code.google.com/p/haxe

One important thing to note is that haXe can be installed on on Windows, Linux, and MacOSX. This way, you don't have to worry about your operating system and can continue working in your environment.

Installing on Windows

Installing haXe on Windows is pretty easy, but there are some caveats that we should avoid.

So, carry out the following steps:

  1. Go to http://www.haxe.org.

  2. Click on the Download link.

  3. There, you will find a link to download the Windows version of the installer. It comes as an executable file.

  4. Run the executable.

Note that if you're working on Windows Vista or Windows 7, you will need to run the executable as Administrator. You can do so by right-clicking on the installer while holding the Shift key down and then clicking on Run as Administrator.

Installing on MacOSX

Installing haXe on MacOSX is very straightforward. Carry out the following steps:

  1. Go to http://www.haxe.org.

  2. Click on the Download link.

  3. There, locate and click on the link to download the OSX Universal Installer.

  4. The installer comes as a DMG image, if it's not automatically mounted; mount it by double-clicking on it.

  5. Go to where the DMG image is mounted and run the installer.

That's it! You have haXe installed on MacOSX!

Installing on Linux

Some distributions have haXe in their repositories, so you may install it from your distribution's repository if it's available.

Alternatively, you can use the Linux Installer to install haXe; it does work on many distributions. Carry out the following steps to install haXe on Linux:

  1. Go to http://www.haxe.org.

  2. Click on the Downloads link.

  3. Find the link to download the Linux version of the installer.

  4. Uncompress the file by using the tar –zxf hxinst-linux.tgz command.

  5. Add execution rights on the installer by using the chmod +x hxinst-linux command.

  6. Run the installer with administration rights either by using the sudo –s command or the su command, and then running ./hxinst-linux.

Now, you should have haXe installed on your Linux machine.

Installing nightly builds

If you need features that are not in the latest release, you can use the nightly builds to easily have access to binaries of what is in the repository without the need of compiling it on your own.

You will be able to find them on the haXe website's Download page for your operating system.

Note that the nightly builds do not come with an installer and therefore, you are advised to first install using the installer, so that it sets up all environment variables and then replaces installed files by the ones from the nightly builds archive.

On MacOSX and Linux machines, you should find them in /usr/lib/haxe, while on Windows, they should be in c:\haxe.

Verifying your installation

You can verify that haXe is correctly installed by opening a terminal and running the haxe command; if haXe is correctly installed, then you should get the help message.

You can also test that Neko is correctly installed by running the neko command. You should again get the help message.

 

Choosing an editor


There are not many editors for haXe, but still there are some that you should know of. Although I do suggest that you look at these because they can help you increase productivity. I do think that it's also important in the beginning to use the haXe compiler (that is, the haxe command) on your own to understand how it works and how it is used. You'll get more and more comfortable as you go through the examples.

FlashDevelop 3

The FlashDevelop IDE supports haXe projects. This is certainly the most advanced haXe code editor on Windows at the time of writing and also, it is an open source software.

FlashDevelop supports auto-completion, project management, syntax highlighting, and compilation rights from the IDE.

You can download FlashDevelop for free from http://www.flashdevelop.org. If you want to have a quick look at it before trying it, the following screenshot shows how it looks:

The TextMate bundle

TextMate is an easy-to-extend text editor for MacOSX. It can be extended by installing "bundles". There's a bundle providing haXe auto-completion, syntax highlighting and compilation from TextMate at http://github.com/freewizard/haxe2.tmbundle. You simply have to download the bundle as a ZIP file and rename it with the .tmbundle extension. Once this is done, double-click it. If you already have TextMate installed, the plugin should get installed.

The following screenshot shows what it looks like with the haXe bundle:

VIM

There are several scripts that you can install to add support for haXe in VIM. Many of these are collected at http://github.com/MarcWeber/vim-haxe. With those scripts, you get syntax highlighting and auto-completion. Although VIM is generally used by people using Linux, it can be used on Windows and MacOSX. This way, one can have the same tools across multiple platforms.

 

Writing your first program


So, you've installed haXe and got some advice in case you need help. Now is the time to get into action by writing your first program: and as usual, it will be a Hello World!

 

Time for action – Writing a Hello World


Let's create an application that will simply display the "Hello World" message. We will use only cross-platform code and will compile it to neko to begin.

  1. Copy the following code in a file named Main.hx

    class Main
    {
       public static function main()
       {
          trace("Hello World");
       }
    }

    Tip

    Downloading the example code for this book

    You can download the example code files for all Packt books you have purchased from your account at http://www.PacktPub.com. If you purchased this book elsewhere, you can visit http://www.PacktPub.com/support and register to have the files e-mailed directly to you.

  2. Open a terminal; go to the directory where you saved Main.hx and type the haxe –main Main –neko helloworld.n command.

  3. Type this command: neko helloworld.n.

  4. You will see the following output:

    Main.hx:5:Hello World

What just happened?

As you've guessed, the program just wrote "Main.hx:5:Hello World" in our terminal and ended.

  • The code: In our code we declare a class named Main, which has a public and static function main. The method trace is a method that allows one to debug an application by printing a message along with the file's name and line number of the call. If you don't really understand what classes are, don't worry, we are going to explain it to you soon.

  • The compilation: The command in the second step compiles the haXe code to neko. Notice that the –main switch that's followed by the name of the class containing the function has to be executed when launching the program. This function has to be a static function named main that takes no parameters.

  • Running the neko code: In the third step, we invoke the neko VM and tell it to execute the helloworld.n file.

 

A program with some interaction


Now that we've gone through the classic "Hello World", let's do something a bit more interesting; how about taking some parameters on the command line? If you're not familiar with commands, this is the usual way to take some information from the user without having to write an interactive program.

 

Time for action – Interacting with the user


Now, we're going to create an application that takes your name as a parameter, greets you, and displays the number of characters in your name.

  1. Copy the following code in a file named Main.hx

    class Main
    {
      public function new()
      {
      
      }
    
      public static function main()
      {
       var name = neko.Sys.args()[0];
       trace("Hello " + name);
       trace("Your name is " + Std.string(name.length) + " characters long.");
      }
    }
  2. Open a terminal; go to the directory where you saved Main.hx and type the haxe –main Main -neko characterCounter.n command.

  3. Type the command (this is an example with my first name):

    neko characterCounter.n Benjamin

  4. You will see the following output:

    Main.hx:12: Hello Benjamin

    Main.hx:13: Your name is 8 characters long.

What just happened?

The program read your name from the command line, greeted you by appending your name to "Hello", and displayed the number of characters that make up your name.

  • The code: You already know the basics about the class and the main function. What is interesting to see here is how we get the arguments. When targeting neko, we can use the args function of neko.Sys. This function takes no parameters and returns an Array of String.

    As you can see, we can access an array's item by its index using the square-brackets notation. Here we are accessing the item at index 0 (arrays are 0-based, that means that the first item is always at index 0).

    Then, we use the trace function that you've already seen to display "Hello" followed by the name of the user. As you can see here, string concatenation is done by using the + operator. It is still quite important to note that there are classes such as StringBuf that can be used to achieve the same behavior, if you are focused on performances.

    You'll also notice that String has a variable named length that allows you to retrieve the number of characters in it.

    By the way, haXe is typed, and here we are using Std.string to convert the length of the string from Int to String. Std.string can be used to convert any value to a String. This is not mandatory here, as when using the + operator, if one of the two values is not an Int nor a Float, the operator will return a String. In this case, all operands will be considered as String.

  • The compilation: Well, as you can see, there's absolutely nothing new in the compilation process. The only thing we've changed is the output file's name.

  • Running the neko code: In the third step, we invoke the neko VM and tell it to execute the characterCounter.n file by passing it an argument: Benjamin.

  • Possible improvements: Our program is quite simple, but if you've some experience with programming, you may have noticed one point where our program may encounter an exception: we are relying on the fact that the user will give us at least one argument, and we access it directly without verifying that it's really there. So, if the user gives us no argument, we will encounter an exception. There are two ways to handle that: either we verify how many arguments the user has given, or we can also try to catch exceptions. This is something that we will explain later.

Pop quiz – basic knowledge

  1. It is possible to install haXe on:

    1. Windows

    2. MacOSX

    3. Linux

    4. Android

    5. iOS

  2. What major version do we use nowadays?

    1. haXe 1

    2. haXe 2

    3. haXe 3

    4. haXe 4

  3. The main function of a program has to be:

    1. static and named main

    2. public and named first

    3. public and static, and named first

  4. The debugging function that prints some text is named:

    1. println

    2. print

    3. trace

    4. debug

 

Summary


In this chapter, we have seen how to carry out your first steps with haXe. In particular, we've seen how to install haXe and how to write haXe programs. We've also seen how you can interact with the user in the console.

Now, let's go to the second chapter in which we will learn about the basic syntax and how to do branching.

About the Author

  • Benjamin Dasnois

    Benjamin Dasnois has always been fascinated by open source software and as such, has been giving courses about Linux in an IT school in France. In the meantime, Benjamin has been following and working with haXe since its beginning and uses it in his professional life. He now works on an open source project, started the integration of haXe into it, and made it work with the technologies that were already in use.

    Browse publications by this author

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