The EnableCompletionRule command turns on the specified completion rule(s) in the Typesetting package for use in 2-D input, while the DisableCompletionRule command turns off the specified completion rule(s) in the Typesetting package for use in 2-D input.

There are too many rules to be able to list them all here, but all are available in the Rules area of the interactive Typesetting Assistant.

As a simple example, if the rule  was enabled for completion, one could enter "BesselJ" within the 2-D editor, then hit the completion key (Ctrl + Space on Windows and Ctrl + Shift + Space on Unix), and one of the presented options will be a formatted BesselJ function (specifically a function  with a symbolic subscript  as a function of a variable , where the  and  are entry points).

It should be noted that functions entered via completion parse in the expected way even if the corresponding parse rule is disabled.