Re: [NTG-context] protected macro vs protected luacall

27 Jan 2023


      On Thu, 2023-01-26 at 23:07 +0100, Hans Hagen via ntg-context wrote:
...
On 1/26/2023 9:33 PM, Henri Menke via ntg-context wrote:
...
\directlua{
   userdata = userdata or {}
   function userdata.test()
     tex.print("\string\\numexpr 17\string\\relax")
   end
}
\tt
\protected\def\test{\directlua{userdata.test()}}
\meaning\test\par
\edef\x{\test}\meaning\x\par
\the\test
\directlua{
   local t = lua.get_functions_table()
   t[\string#t + 1] = userdata.test
   token.set_lua("test", userdata.test, \string#t, "protected")
}
\meaning\test\par
\edef\x{\test}\meaning\x\par
\the\test
from the code it looks like we're talking plain luatex ...
\the is very selective and doesn't work for all primitives or macros
compare it to \number which accepts any number representation
following 
it while \the doesn't work ok 123
that said, your set_lua is wrong and passes a function as well as an
index
\directlua{
    lua.get_functions_table()[999] = function()
      tex.print("\string\\numexpr 17\string\\relax")
    end
    token.set_lua("test", 999)
}
\the    \test % needs the \numexpr
\number \test % doesn't
\count0 \test % needs the \numexpr
\count0=\test % doesn't
etc
Thanks for pointing out my mistake. Your example works fine but now the
luacall is no longer protected and will therefore fully expand in
\edef. So do I understand this correctly that there is no way to make
the second \the\test work?


\directlua{
    lua.get_functions_table()[999] = function()
      tex.pri
nt("\string\\numexpr 17\string\\relax")
    end
}

\tt
\directlua{token.set_lua("test", 999)}
\meaning\test\par % expandable luacall 999
\edef\x{\test}\meaning\x\par % macro:->\numexpr 17\relax
\the\test % 17

\directlua{token.set_lua("test", 999, "protected")}
\meaning\test\par % luacall 999
\edef\x{\test}\meaning\x\par % macro:->\test
\the\test % ! You can't use `luacall 999' after \the.

\bye


Cheers, Henri
...
Hans
-----------------------------------------------------------------
                                           Hans Hagen | PRAGMA ADE
               Ridderstraat 27 | 8061 GH Hasselt | The Netherlands
        tel: 038 477 53 69 | www.pragma-ade.nl | www.pragma-pod.nl
-----------------------------------------------------------------
_____________________________________________________________________
______________
If your question is of interest to others as well, please add an
entry to the Wiki!
maillist : ntg-context@ntg.nl / 
https://www.ntg.nl/mailman/listinfo/ntg-context
webpage  : https://www.pragma-ade.nl / http://context.aanhet.net
archive  : https://bitbucket.org/phg/context-mirror/commits/
wiki     : https://contextgarden.net
_____________________________________________________________________
______________