Re: [NTG-context] About xstring and ConTeXt

8 Jul 2020

      On 7/8/2020 12:00 AM, Jairo A. del Rio wrote:
...
Yep, now it finally works. Certainly it requires a few more lines. I was 
going to rewrite some TikZ code which was too dependent on LaTeX and 
xstring was the last stone on the shoe. Thank you a lot, Phelype and 
Wolfgang (I didn't know about push/popmacro either and now it's in my 
to-do readings).
We can have a module that takes care of some things, like

\usemodule[system-aliasing]

\registeralias\unexpanded\normalunexpanded  % preset
\registeralias\expanded  \normalexpanded    % preset

\registeraliasfile{rubish.tex}    % any file with that name
\registeraliasfile{generic/*.tex} % a bit more explicit

after which

\input rubish.tex
\input generic/foo.tex

(or whatever way it's loaded) will (hopefully) work ok. But as a module, 
not in the core, because we don't want additional overhead for third 
party stuff, but ok on user demand. Of course one cannot expect the 
context dev to keep a list of files that need such a treatment.

Hans
...
Jairo :D
El mar., 7 de jul. de 2020 a la(s) 16:31, Phelype Oleinik 
(phe.h.o1@gmail.com mailto:phe.h.o1@gmail.com) escribió:
On Tue, Jul 7, 2020 at 6:21 PM Jairo A. del Rio
    mailto:jairoadelrio6@gmail.com> wrote:
     >
     > Thank, Wolfgang! Both methods work, but both fail with the
    following example:
     >
     > \pushmacro\unexpanded
     > \let\unexpanded\normalunexpanded
     > \input xstring
     > \popmacro\unexpanded
     > \starttext
     > \StrGobbleLeft{bcdef}{4}
     > \stoptext
     >
     > The log says:
     >
     > tex error > tex error on line 6 in file ./tests.tex: ! This can't
    happen (prefixed command)
     >
     >
     > <argument> \unexpanded {
     >
     > f}
     >
     > \xs_execfirst #1#2->#1
     >
     > However, some others work.
As I said, the internals of `xstring` still use \unexpanded which, after
    you do \popmacro\unexpanded, will mean e-TeX's \protected, rather than
    \unexpanded, which are quite different.  To be on the safe side, you'd
    need to wrap every `xstring` command in
         \pushmacro\unexpanded
         \let\unexpanded\normalunexpanded
         <xstring stuff>
         \popmacro\unexpanded
    to make sure that \unexpanded means what `xstring` expects.
The *proper* way to make `xstring` work in ConTeXt would be something
    like Circuitikz does:
         \ifcsname normalunexpanded\endcsname
           \let\pgfcircutil@unexpanded\normalunexpanded
         \else
           \let\pgfcircutil@unexpanded\unexpanded
         \fi
    then use \pgfcircutil@unexpanded in the code, which will always have the
    same meaning.  That, of course, requires an update to `xstring`.
Phelype
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