[texhax] Defining a command which runs differently based ion input argument

[Philip Taylor (Webmaster, Ret'd)]

Uwe Lueck wrote:

> Active characters can allow tayloring syntax for special purposes.
> It is difficult and can be very tedious to program, but without
> category codes this possibility just doesn't exist.

And as I can confidently state from a near lifetime's
experience, "tayloring" syntax is at the very heart
of creative programming.

Philip TAYLOR