The NashornFunction plugin is a demo plugin showing how to render a Nashorn script into a jEdit plugin. The principal functionality of the plugin is programmed in some Nashorn script's function, and then this function is included into the plugin's Java code via JavaScriptShell.runScriptInvocable(...).
The JAR file NashornFunction.jar should be copied to the usual place of jEdit's plugins. This place can be [jEdit application directory]/jars or [jEdit settings directory]/jars. The accompanying Nashorn script demo_script_function.js is found in the repository subfolder /scripts. This script should be copied into [jEdit settings directory]/scripts. This should be enough to start the plugin.
The plugin can be configured via the plugin options. The plugin's accompanying Nashorn script contains two functions: demoBorder and demoScroller. In the options panel, each of them can be chosen to be invoked. The behaviour of the function demoScroller depends on the presence of the argument. In the options panel, another place of the script can be selected.
To extend or change the functionality of the plugin, one has to include other (useful) functions into the script demo_script_function.js, or write another (useful) Nashorn script, and then to configure the plugin in the options panel accordingly.