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Message-ID:  <7d3bbc2fc1d5f54510c7ffebd8d5260ff396d920.camel@sipsolutions.net>
Date:         Mon, 1 Apr 2019 12:52:35 +0200
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From:         Benjamin Berg <benjamin@SIPSOLUTIONS.NET>
Subject: Re: Rescanning first token of environment when no optional argument is given
To:           LATEX-L@LISTSERV.UNI-HEIDELBERG.DE
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Status: R

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On Mon, 2019-04-01 at 09:41 +0200, David Kastrup wrote:
> Benjamin Berg <benjamin@SIPSOLUTIONS.NET> writes:
>=20
> > Hi,
> >=20
> > 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
> >=20
> > 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.
>=20
> 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

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