[texhax] Force double expansion ?
Philip Taylor
P.Taylor at Rhul.Ac.Uk
Wed Jul 16 22:59:11 CEST 2014
Uwe Lueck wrote:
> Are you really asking for the simple
>
> \expandafter\expandafter\expandafter \futurelet
> \expandafter\expandafter\expandafter \nexttok
> \expandafter\expandafter\expandafter \analysenexttok
It would seem not, Uwe, since when used in the context given, it yields
an error :
> % !TeX Program=XeTeX
>
> \def \examinenexttok {\message {Nexttok: \meaning \nexttok}}
> \def \whatever {\csname namespace: }
> \let \endwhatever = \csname
> \expandafter \def \csname namespace: test\endcsname {"namespace: test"}
> \tracingall
> \expandafter\expandafter\expandafter \futurelet
> \expandafter\expandafter\expandafter \nexttok
> \expandafter\expandafter\expandafter \analysenexttok
> \whatever test\endwhatever
> \end
which yields :
This is XeTeX, Version 3.1415926-2.5-0.9999.3 (TeX Live 2013/W32TeX)
restricted \write18 enabled.
entering extended mode
(./untitled-12.tex
{vertical mode: \tracingstats}
...
{\expandafter}
{\expandafter}
{\expandafter}
{\expandafter}
{\expandafter}
{\expandafter}
\whatever ->\csname namespace:
{\expandafter}
{\expandafter}
{\expandafter}
{\csname}
{\csname}
! Missing \endcsname inserted.
<to be read again>
\end
l.12 \end
?
Philip Taylor
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