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