[NTG-context] arguments to ctxlua

30 Mar 2010

      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