# [NTG-context] arguments to ctxlua

When I have a Lua function with 2 arguments:
\startluacode
function f(a,b)
...
\stopluacode

called through:
\def\callf#1#2{\ctxlua{f("#1","#2")}}

and do this actually with one argument:
\callf{one}


then I find that the absent argument b in f(a,b) is not nil but a string of length 1.

That is a bit of a nuisance because I would like to use the Lua idiom:
function f(a,b)
local b = b or default
but that is frustrated by the behaviour shown.


Is this an artifact of either luatex or ConTeXt? Can it be avoided such that in this case b will be nil?


Hans van der Meer

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