mniip:

Lol simon already started developing method of adding new elements

He did? I haven't seen anything on github about that, unless he hasn't even put anything on there yet.

I was trying to think of a way to do this recently too. What I thought of is that new elements are copies of existing elements and have their type set as that particle so they have all of it's properties. There would then be some flag that tells it it's actually a custom element, and to run custom update and graphics functions for it. It would also show up in the menu as another element, and also have separate properties than the ones in ptypes[]
Maybe there would also be a way to add a reaction to it with a line of lua code (ex. tpt.addreaction("PROT","ELEC","HYGN")), and the reaction is done in c, to reduce lag. A way to make custom graphics functions would have to be added too.

I will probably do this eventually, if another way is not made by someone else, and try to get it into the official version. I have been really busy recently, and so it wouldn't be anytime soon.

No, simon showed us two executables, in one PT_NUM was precompiler macro, in another it was a variable, and people checked which lags more
edit: btw i already made something...with lua that could add custom graphic functions