Hi Manuel, Everybody, I am just getting into LuaLaTeX. I needed to do some work with MetaPost. While working I came across a kudo. That is once inside the mblibcode environment one can not call Lua. THIS I consider a missing feature and a VERY important one. I figured it should not be not hard to add in this functionality, Which as it seems it is not. I look into the luamplib manual and notice that all that was needed was to patch luamplib.addline. All that was needed was to create a syntax/command that was inside the MetaPost code noticed this command extract the function call and have it executed. I have done this. It is just a couple of lines of code. On the TeX of LuaLaTeX side, one can know write \begin{mplibcode} <some normal Metapost commands> mplibcodedolua(<Lua function call>) <more Metapost commands> \end{mplibcode} My questions are: 1) Is there any interest in such a function. As I mentionedabove this is not a Lua function, just syntatic sugar so that the provide Lua function gets called. 2) What should it be called. mblibcodedolua ? I am asking this before I present my code here so that my code presents a rounded picture. regards Keith.