Inline functions
In Nintex Workflow 2013, an inline function, also known as a string function, is a .NET Framework static method that can be used like any other workflow reference in workflow actions. Nintex Workflow 2013 parses, evaluates, and resolves the reference by invoking the method and replacing the reference with the value returned from that method.
You can create custom inline functions, either by defining a function alias for an existing .NET Framework static method, or by developing a new .NET Framework static method and then defining a function alias for it. For more information about developing, defining, and invoking inline functions, see Working with inline functions.