On 3/12/2023 2:24 PM, Bruce Horrocks via ntg-context wrote:
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? So, four optional with mandate {} plus a fallback to an optional []
\starttext \tolerant\def\mycommand#=#=#=#=#:[#5]% {\ifparameter#1\or(1:#1)\fi \ifparameter#2\or(2:#2)\fi \ifparameter#3\or(3:#3)\fi \ifparameter#4\or(4:#4)\fi \ifparameter#5\or[5:#5]\fi} \startbuffer \mycommand{aa}{bb}{cc} \mycommand{aa}{bb}{cc}{dd} \mycommand{aa}{bb}{cc}{dd}[ee] \mycommand{aa}{bb}{cc} \mycommand{aa}{bb}{cc}{dd} \mycommand{aa}{bb}{cc}{dd}[ee] \stopbuffer \typebuffer \startlines \getbuffer \stoplines \stoptext I'm not saying that it's the best solution, you can add \protected in front of the \def if needed. Hans ----------------------------------------------------------------- Hans Hagen | PRAGMA ADE Ridderstraat 27 | 8061 GH Hasselt | The Netherlands tel: 038 477 53 69 | www.pragma-ade.nl | www.pragma-pod.nl -----------------------------------------------------------------