Extending AQL with User Functions

AQL comes with a built-in set of functions, but it is not a fully-featured programming language.

To add missing functionality or to simplify queries, users may add their own functions to AQL in the selected database. These functions can be written in JavaScript, and must be registered via the API; see Registering Functions.

In order to avoid conflicts with existing or future built-in function names, all user functions must be put into separate namespaces. Invoking a user functions is then possible by referring to the fully-qualified function name, which includes the namespace, too; see Conventions.