I came across an interesting issue (for me), which is probably the beginner, but accompanied me for a long time. The problem is probably that I do not understand very well the principles of operation LuaTeX and while I want to do more complex things. I think many beginners will love it when someone indicate solutions. My problem is that I need in my complex application, evaluate parameters of Lua functions, which are a TeX macros (respectively their expanded contents). I did not discover the possibility of expansion of TeX macros, which is a parameter Lua function. Here are three examples in which I demonstrate the problem. 1. In first example is function parameter a text string. \ctxlua{pars('a,b,c,d,e')} Everything works as expected - evaluation of parameter was carried out OK - comma separator was found and replaced. 2. In second example is a function parameter a TeX macro \printaction. Macro expanded before entering the function. Everything works as expected too - comma separator is found and replaced: \ctxlua{pars('\printaction')} 3. The third example of my most interesting. Function parameter in example is a TeX macro \printaction which not expanded, respectively expanded only when I printing it to TeX. Parameter of function is string "\printaction" in which it is futile to look for a comma separator. Comma not be found, although the content of macro face that is so. \ctxlua{pars('\\printaction')} Is there a possibility for this case, as in some way to save to Lua variable content of macro (of course expanded)? I note that this example is important for me and I would like there to be a Lua function (eg "expandtostring"), which expanded a TeX macro into variable until inside function Lua. I hope the my example (with comments) will be comprehensible and I apologize if the solution is too trivial. I searched dozens of examples, but I come across something similar. Thanx very much - Jaroslav Here is example: \startluacode function pars(inppar) strpar=tostring(inppar) -- here I need a function "expandtostring(inppar)" gsubstr=string.gsub(strpar, ',', ';') tex.print("Input parametr (string or macro): ") tex.write(inppar) tex.print("\\par") tex.print("Content of string (macro): "..strpar) -- There will always be expansion tex.print("\\par") tex.print("Length string (macro): "..string.len(inppar).."\\par") tex.print("Length of content : "..string.len(strpar).."\\par") tex.print("Occurrence of the commma separator: "..gsubstr.."\\par") end \stopluacode \def\printaction{x,y,z} \starttext Example 1) Function parameter in first example is a text string. Everything works as expected - comma separator is found and replaced: \ctxlua{pars('a,b,c,d,e')} \blank[big] Example 2) Function parameter in second example is a TeX macro \backslash printaction which expanded before entering the function. Everything works as expected too - comma separator is found and replaced: \ctxlua{pars('\printaction')} \blank[big] Example 3) The third example of my most interesting. Function parameter in example is a TeX macro \backslash printaction which not expanded, respectively expanded only when I printing it to TeX. Parameter of function is still string "\backslash printaction" in which it is futile to look for a comma separator. Comma not be found, although the content of macro face that is so. Is there a possibility for this case, as in some way to save to Lua variable content of macro (of course expanded)? \ctxlua{pars('\\printaction')} \stoptext