> On 13 Mar 2023, at 21:39, Hans Hagen via ntg-context <ntg-context@ntg.nl> > wrote: > > 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
Thanks Hans, This works well. I'll try and add something to the Wiki but I don't understand how #: does what it does. Regards, — Bruce Horrocks Hampshire, UK ___________________________________________________________________________________ If your question is of interest to others as well, please add an entry to the Wiki! maillist : ntg-context@ntg.nl / https://www.ntg.nl/mailman/listinfo/ntg-context webpage : https://www.pragma-ade.nl / http://context.aanhet.net archive : https://bitbucket.org/phg/context-mirror/commits/ wiki : https://contextgarden.net ___________________________________________________________________________________