Since you mentioned shorter character stuff, I'll point out that you're bringing $calc to the $str just to be able to use the empty pattern // to get the correct number of match, is the arguement there that using // as a pattern is much faster than using a pattern /C/g? Because the $regsubex that doesn't use $calc (GM of slowness) and use such a pattern would be shorter (and probably just as fast pcre wise) than what you used:
%ret = $regsubex($str($chr(32),$calc($comchan(%who,0) -1)),//g,$+($nick($comchan(%who,\n),%who).idle,:,$left($nick($comchan(%who,\n),%who,a,r).pnick,1),$comchan(%who,\n)))
vs
%ret = $regsubex($str(a,$comchan(%who,0)),/a/g,$+($nick($comchan(%who,\n),%who).idle,:,$left($nick($comchan(%who,\n),%who,a,r).pnick,1),$comchan(%who,\n)))
