[NTG-context] Dig out contents of the TeX macro using Lua

Jaroslav Hajtmar hajtmar at gyza.cz
Tue Jul 14 22:41:15 CEST 2015


Hello ConTeXist.
I hope that my crazy questions not much bother.
This time I needed to get to the fair value of the parameter, delivering 
to lua function over the content macros.
Obviously it's my misunderstanding of the functioning of expansion in 
case maker with optional parameters, or you really can not explain the 
functioning of the transmission values. It seems that is passed to a 
sort of reference as to the actual contents of the macro perhaps can not 
even get through Lua. Or did they?
The following minimal example, perhaps explain what going on.

The question ultimately: Is there any alternative how using Lua somehow 
easily evaluate the macro content? For example to determine whether two 
different macros have the same content?

Jaroslav Hajtmar

here is minimal example:

\starttext

This works as expected:

\def\makrowithAAAAcontent{AAAA}

\edef\testparameter#1{%
\startluacode
local parameter='#1'
if parameter=='AAAA' then context('TRUE. ') else context('FALSE. ') end
context('Parameter '..parameter..' has length '..string.len(parameter))
\stopluacode
}%

\type{\makrowithAAAAcontent} -- \makrowithAAAAcontent

Test is \testparameter{BBBB}

Test is \testparameter{AAAA} % OK

Test is \testparameter{\makrowithAAAAcontent} % OK

But what about with this: ???


% initialize values
\startluacode
A={}
for i=1,50 do A[i]='Record '..tostring(i) end
A[25]='AAAA'
\stopluacode


\def\makrowithAAAAcontent{AAAA}

\def\lastname{\dosingleempty\dolastname}%
\def\dolastname[#1]{\doifsomethingelse{#1}{\ctxlua{context(A[#1])}}{\makrowithAAAAcontent}}%


\type{\lastname} - \lastname

\type{\lastname[2]} - \lastname[2]

\type{\lastname[5]} - \lastname[5]

\type{\lastname[25]} - \lastname[25]





\edef\readandprocessparameters#1#2{%
\startluacode
local parameter1='#1'
if parameter1=='AAAA' then context('Test '..parameter1..' = AAAA is 
TRUE. ') else context('Test '..parameter1..' = AAAA is FALSE. ') end
context('Parameter 1 = '..parameter1..' has length 
'..string.len(parameter1))
context('\\crlf')
local parameter2='#2'
if parameter2=='AAAA' then context('Test '..parameter2..' = AAAA is 
TRUE. ') else context('Test '..parameter2..' = AAAA is FALSE. ') end
context('Parameter 2 = '..parameter2..' has length 
'..string.len(parameter2))
context('\\crlf')
\stopluacode
}%


\readandprocessparameters{AAAA}{BBBB}

%Test is \readandprocessparameters{\lastname[25]}{\lastname} % Crashed

\readandprocessparameters{\\lastname[25]}{\\lastname}

\stoptext



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