Joseph Wright wrote: > On 07/08/2010 14:57, Arno Trautmann wrote: >> Hi all, >> >> I am looking for a way to define an environment that takes a range as an >> optional argument. This should be given in the following way: >> >> \begin{environment}(15:5.23) >> >> with a default value, say (1:3). The two limits should then be parsed as >> single arguments which are separated by the colon. >> I am trying to do this with xparse and got some possible solutions with >> the u and d argument type, but I didn’t manage to get the parentheses >> optional. I guess what I need is some kind of an optional u argument … >> >> Does anyone have a suggestion how to easily implement these requests? >> >> cheers >> Arno >> > Parse the argument first as a 'd', then use \SplitArgument to do the > subsequent work: Nice, I totally forgot about the \SplitArgument … Thanks for your quick answer, that works fine. But unfortunately it does not solve my problem due to other reasons. cheers Arno