I have an existing macro that I'd like to extend. The current definition is \define[3]\mycommand{...} which I'd like to extend to take an optional 4th parameter plus an optional setup parameter. Thus I currently invoke it as: \mycommand{aa}{bb}{cc} and I'd like to be able to extend it so that any of the following can be used: \mycommand{aa}{bb}{cc} \mycommand{aa}{bb}{cc}{dd} \mycommand{aa}{bb}{cc}{dd}[ee] or \mycommand[ee]{aa}{bb}{cc}{dd} % if this is more the ConTeXt way where {dd} is the optional extra parameter and, if it is present, then [ee] can also be optionally added (because it controls how {dd} is printed). If it helps, the actual body of the macro can easily be a call to Lua so it's fine if the function takes 5 params where 4 and 5 can be nil or empty strings. I've trawled through syst-aux.mkiv but it only covers optional numbers of [ ] or { } but not combinations of both (which given the vast numbers of combinations is perhaps not surprising!). Have I missed something obvious that would help me? Regards, — Bruce Horrocks Hampshire, UK