You can use the Script Engine also in your application, the Object Pascal statements in your Application are parsed by the Engine and executed. The Scripting Engine adds the capability of an Object Pascal Interpretator.

You can extend your application with extra functions, without the need to recompile your application.

To add them to your end-use application you can use LizaJet Installer. You can  create a new package with the required script file,  which your end-user installs manually.
You can also automate it for your user by providing an upgrade package  that includes the script file.

Another frequently used method is combining pieces of code with a data dictionary. Your client applications can use script to check the validity of user input before the data is sent to the database.