Plugins
The Evaluator can be extended with additional 'functions', these extensions are called 'Plugins'. Every plugin provides at least one function. There may be additional functions provided by the display driver, you'll find this information in the driver documentation.
If a plugin provides only one function, the function is named like the plugin itself. If it provides more functions, every function has a prefix 'plugin_name::'. This is necessary to allow auto-loading in the future (at the moment, all plugins are linked statically to the executable. Someday in the future, we will support dynamic on-demand loading of plugins).