On Mon, 2019-04-01 at 09:41 +0200, David Kastrup wrote: > Benjamin Berg <[log in to unmask]> writes: > > > Hi, > > > > On Sun, 2019-03-31 at 18:57 -0300, Phelype Oleinik wrote: > > > If you can't switch the catcode of & before looking for the > > > optional argument, as David suggests > > > > David has a good point, I could handle the optional argument parsing > > myself and ensure that the case works correctly. It may not be trivial, > > but it should be reasonably easy. > > It should be trivial. You just use the provided mechanism exactly as > you did before (though naming it differently) and call it last thing in > your argumentless wrapper environment after setting up catcodes. That > way the argument scanning only commences once catcodes are settled. Well, I do have an optional parameter that disables the catcode changes (which I know realize might have been a bad idea). That said, it would still be rather safe to make the change, parse the optional parameter and undo the change again afterwards when desired. Or maybe I should just bite the bullet and create two almost identical environments for this. Benjamin