1. Code example

2. See also

3. References

4. External links

Vala is an object-oriented programming language with a self-hosting compiler that generates C code and uses the GObject system.

Vala is syntactically similar to C# and includes notable features such as: anonymous functions, signals, properties, generics, assisted memory management, exception handling, type inference, and foreach statements.^[2] Its developers, Jürg Billeter and Raffaele Sandrini, wanted to bring these features to the plain C runtime with little overhead and no special runtime support by targeting the GObject object system. Rather than compiling directly to machine code or assembly language, it compiles to a lower level intermediate language. It source-to-source compiles to C, which is then compiled with a C compiler for a given platform, such as GCC.^[3]

For memory management, the GObject system provides reference counting. In C, a programmer must manually manage adding and removing references, but in Vala, managing such reference counts is automated if a programmer uses the language's built-in reference types rather than plain pointers.

Using functionality from native code libraries requires writing vapi files, defining the library interfacing. Writing these interface definitions is well-documented for C libraries, especially when based on GObject. However, C++ libraries are not supported. Vapi files are provided for a large portion of the GNOME platform, including GTK+.

Vala was conceived by Jürg Billeter and was implemented by him and Raffaele Sandrini, finishing a self-hosting compiler in May 2006.^[4]

Code example

A simple "Hello, World!" Vala program:

void main () {

}

A more complex version, showing some of Vala's object-oriented features:

class Sample : Object {

    void greeting () {        stdout.printf ("Hello World\");    }        static void main (string[] args) {        var sample = new Sample ();        sample.greeting ();    }

}

An example using GTK+ to create a GUI "Hello, World!" program (see also GTK+ hello world):

using Gtk;

int main (string[] args) {

    Gtk.init (ref args);        var window = new Window ();    window.title = "Hello, World!";    window.border_width = 10;    window.window_position = WindowPosition.CENTER;    window.set_default_size (350, 70);    window.destroy.connect (Gtk.main_quit);        var label = new Label ("Hello, World!");        window.add (label);    window.show_all ();        Gtk.main ();    return 0;

}

The last example needs an extra parameter to compile on GNOME 3 platforms:

valac --pkg gtk+-3.0 hellogtk.vala

See also

• Genie, a programming language for the Vala compiler with a syntax closer to Python.
• Shotwell, an image organiser written in Vala.
• Geary, an email client written in Vala.
• Elementary OS, a Linux distribution with a desktop environment programmed mostly in Vala.

References

External links

• {{Official website|https://wiki.gnome.org/Projects/Vala}}
• [https://sourceforge.net/projects/valatowindows/ ValaToWindows], Vala compiled binaries for Windows
• [https://wiki.gnome.org/Projects/Libgee LibGee], a collection library for Vala.
• API Documentation
• Vala sample code for beginners
• [https://wiki.gnome.org/Projects/Vala/Documentation#Projects_Developed_in_Vala List of Vala programs]
• [https://code.google.com/p/web-vala/wiki/GettingStarted web-vala], a simple web application framework for Vala

Comparison with other languages

• [https://wiki.gnome.org/Projects/Vala/ValaForJavaProgrammers Vala and Java]
• [https://wiki.gnome.org/Projects/Vala/ValaForCSharpProgrammers Vala and C#]
• [https://code.google.com/p/vala-benchmarks/ Benchmark of Vala versus C# and C]
• [https://code.google.com/p/vala-benchmarks/wiki/BenchResults More Vala benchmarks]

• Nguyen Khac Nhu
• Nguyen Kieu Oanh
• Nguyen Kuok Shi
• Nguyen Lam
• Nguyen Linh Chi
• Nguyen Manh Dung
• Nguyen Manh Hung
• Nguyen Manh Tuan
• Nguyen Minh Chau (footballer)
• Nguyen Minh Chau (novelist)
• Nguyen Minh Duc
• Nguyen Minh Phuong
• Nguyen Minh Tam
• Nguyen Minh Tu
• Nguyen Minh Tung
• Nguyen Ngoc
• Nguyen Ngoc Anh (footballer)
• Nguyen Ngoc Anh (swimmer)
• Nguyen Ngoc Duy
• Nguyen Ngoc Nhu Quynh
• Nguyen Ngoc Thanh
• Nguyen, Peter
• Nguyen Phong Hong Duy
• Nguyen Phuong Linh
• Nguyen, Pierre