AngelScript, also known as Angelcode Scripting Language, was originally developed by Andreas Jönsson as a cross-platform scripting library. In other words, it allows you to write a script — a computer program — that will work the same regardless of the computer platform being used. It has been released under a zlib license, meaning it is available free to users.
AngelScript works by creating and running a virtual machine (VM) inside the computer, with the script then running on the VM. This means an AngelScript script will work the same on any computer platform — Windows, Macintosh, Linux, or other. The VM also allows the script to exchange data with other programs running on the computer. This means AngelScript can be used to extend or add capabilities to other programs that allow extensions to be added. An example would be an AngelScript scientific calculator script to evaluate a mathematical expression that, in turn, calls a graphics script that will display a graph of that mathematical expression.
AngelScript scripts are written using a C/C++ syntax, allowing anyone with some experience in using those languages to easily write a script. The AngelScript VM itself takes care of the details. That includes things such as memory management and pointers, which can cause problems when using C/C++.
It is designed to run on different platforms, so AngelScript is not available as an application you would download, install, and run, unless a third party has made it available as such. Normally, the user must download the source code, written in C/C++, and then compile it for a particular computer platform. As of December 2010, AngelScript platforms available included Win32®, Linux®, FreeBSD®, Mac OS X®, Dreamcast™, PlayStation® Portable, PlayStation® 2, PlayStation® 3, Xbox®, and Xbox 360®. Work was underway on VMs for the Windows® Mobile, Nintendo® DS, and Android™ platforms, but there was no information on when the VMs would be available on these platforms.
The ability to have a program work in the same way on different platforms makes AngelScript attractive to software publishers. Some games publishers are releasing games that have been written using AngelScript and include the AngelScript VM for the particular platform. This allows them to release the same game at the same time for different platforms. Development of AngelScript, and improvements in VMs for various platforms, is ongoing. An Internet search can help you find the most recent stable VM for your platform.