In case you are missing a certain feature or functionality in Hollywood, you can write a plugin which adds it to the language. Writing your own plugin can also be helpful in case your script needs to do certain CPU-intensive calculations which are best implemented in native code for an optimal performance.
Writing plugins is really easy. Hollywood's plugin interface is public, fully documented and all necessary files are available for free download from the official Hollywood portal. The Hollywood SDK comes with over 300 pages of detailed documentation and several examples that help you to get started with plugin development.
Please visit the official Hollywood portal at http://www.hollywood-mal.com/ to download the latest Hollywood SDK. It contains all the developer materials you need for building your own Hollywood plugins.