I've tried with a wrapper and it seems to work fine. However, changing
definitions "on the fly" to make xstring usable seems to break things in
ConTeXt... Whatever. I guess I will have to find out other command
redefinitions in ConTeXt.

Thank you very much, Phelype.

Jairo :)

El mar., 7 de jul. de 2020 a la(s) 13:54, Phelype Oleinik (
phe.h.o1@gmail.com) escribió:

> Hi Jairo,
>
> ConTeXt's \unexpanded is e-TeX's \protected, so the error boils down to
> something like: \edef\x{\unexpanded{#}}, which works in Plain but not in
> ConTeXt.
>
> Usually packages that claim to be generic have to cope with that.
> xstring would need to do (in a ConTeXt-specific loader):
>     \let\xstring@unexpanded\normalunexpanded
> and
>     \let\xstring@unexpanded\unexpanded
> in Plain and LaTeX loaders, then then use \xstring@unexpanded in the
> code.  But `xstring` doesn't claim (that I found, at least) to be
> compatible with ConTeXt, so it's understandable: though if it is
> compatible with Plain, it wouldn't be hard to adapt to ConTeXt.
>
> That said, you can load `xstring` if you do:
>      \let\unexpanded\normalunexpanded
>      \input xstring.tex
>      \let\unexpanded\protected
> but the internals of the package will probably be comprimised by the
> misuse of (ConTeXt) \unexpanded.
>
> Phelype
>
> On Tue, Jul 7, 2020 at 3:40 PM Jairo A. del Rio <jairoadelrio6@gmail.com>
> wrote:
> >
> > Reading about macro bundles meant to be generic (format agnostic), some
> of them work in plain/LaTeX, but crash when loaded on ConTeXt. The
> following happens with xstring.tex
> >
> > tex error > tex error on line 372 in file xstring.tex: ! Illegal
> parameter number in definition of \xs_reserved_C
> >
> >
> > <to be read again>
> >
> > 1
> >
> > \xs_newlines ->\unexpanded {}\xs_def \xs_arg_i {##1
> >
> > }
> >
> > \xs_newmacro_ ...name \xs_myarg }\edef \xs_reserved_C {\unexpanded
> \expandafter {\xs_newlines
> >
> > }\edef \noexpand \xs_call }\edef \xs_reserved_D {...
> >
> > l.372 \xs_newmacro\StrRemoveBraces{}{1}{1}
> >
> > {%
> >
> >
> > <empty file>
> >
> >
> > You meant to type ## instead of #, right? Or maybe a } was forgotten
> somewhere
> >
> > earlier, and things are all screwed up? I'm going to assume that you
> meant ##.
> >
> > I've tried changing the catcode regime, but with no effect.
> >
> > Don't misunderstand me. I'm aware of ConTeXt capabilities and string
> manipulation via Lua. My question is more like: "Why doesn't xstring.tex?"
> >
> > Sorry if my question is outside the scope of ConTeXt
> developers/maintainers. Thank you very much.
> >
> > Jairo :)
> >
> >
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