Hi list! See the following example: \startluacode userdata = userdata or {} --Toy example --My actual function receives an argument, but the problem remains the same userdata.myfunction = function() return "343327959841638047651959775267761420323" .. "657838053757849835434002826851807933276" .. "324327913964298509889902373459201557839" .. "84828001486412574060553756854137069878601" end interfaces.implement{ name = "myfunction", public = true, actions = function () context(userdata.myfunction()) end } \stopluacode \def\colorfulnumbers#1{\colored[h=\luaexpr{40*#1},s=1,v=1]{#1}\ }% \starttext %It doesn't work %\handletokens{\myfunction}\with\colorfulnumbers \expandafter\handletokens\expandafter{\myfunction}\with\colorfulnumbers \stoptext As readily seen from my example, I want to color each figure of the numbers generated by a Lua function. However, the use of \expandafter's is cumbersome in this case. I don't want to loop over the result in Lua because I want to be able to apply \handletokens...\with... (or another macro with a similar purpose) with different macros at the TeX end once Lua has delivered results. How should I do it in ConTeXt? Thanks in advance. Cordially, Jairo