Re: [NTG-context] TeX capacity exceeded - in Lua block - why?

16 Jul 2015


      On 7/16/2015 10:55 AM, Procházka Lukáš Ing. - Pontex s. r. o. wrote:
...
Hello,
On Thu, 16 Jul 2015 10:27:48 +0200, Hans Hagen  wrote:
...
On 7/16/2015 10:20 AM, Procházka Lukáš Ing. - Pontex s. r. o. wrote:
...
Hello,
why this code:
----
\def\GG{\ifmmode G_G\else$\GG$\fi}
because in math mode \GG expands \GG which expands \GG ....
I want to just pass G_G in math mode, so it seems to me that "\ifmmode
G_G..." does the check.
The macro should write G + "lower index G" for both math and non-math
scope.
so

\def\GG{\ifmmode G_G\else$G\low{G}$\fi}

or

\def\GG{\mathematics{G_G}}

now you do a check in \GG and then call for \GG again so \GG again does 
a check etc etc ... you just enforce endless recursion
...
And, in non math scope, the macro should just enclose itself by $...$
(or \m{...})...
And, this works well in TeX code:
----
\def\GG{\ifmmode G_G\else$\GG$\fi}
\starttext
   \GG $\GG$
   \startitemize[][]
     \sym{\GG} \GG
     \sym{$\GG$} $\GG$
     \sym{\m{\GG}} \m{\GG}
     \item End
   \stopitemize
\stoptext
----
So how to rewrite the itemization into Lua?
...
maybe you mean:
\def\GG{\ifmmode G_G\else$GG$\fi}
... Could be \def\GG{\ifmmode G_G\else$G_G$\fi}, too, but why not
\def\GG{\ifmmode G_G\else$\GG$\fi} (seems to me be simpler as the macro
definition - which may be more complicated - appears only once)?
Lukas
...
...
\starttext
   \GG $\GG$ % OK
   \startitemize[][]
     \sym{\GG} \GG % OK
   \stopitemize
\startluacode
     context.startitemize()
       context.sym([[\GG]])
       context("Abc")
     context.stopitemize()
   \stopluacode
\stoptext
----
fails with:
"
....
tex error       > tex error on line 14 in file
d://Lukas/Docs/Ull-Gra/Test/Abr.mkiv: ! TeX capacity exceeded, sorry
[input stack size=10000]
\GG ->\ifmmode G_G\else $\GG
                              $\fi
\GG ->\ifmmode G_G\else $\GG
                              $\fi
\GG ->\ifmmode G_G\else $\GG
                              $\fi
\GG ->\ifmmode G_G\else $\GG
                              $\fi
\GG ->\ifmmode G_G\else $\GG
                              $\fi
\GG ->\ifmmode G_G\else $\GG
                              $\fi
....
l.14   \stopluacode
....
"
I need to call "\GG" from within Lua, and the real macro name is created
run-time (contrary to this MNWE; so to be \GG, \HH, \Fik etc. - the name
is obtained from a Lua table as a string).
I cannot understand why all TeX calls are OK but the problem appears in
Lua block...
Best regards,
Lukas
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