A program, located in blockland base folder, that works like a scripting GUI... basically is one.
It allows you to create a new CS file, and then enter your script.
When you click 'Syntax Check' it checks the entire code for errors as it would if it were loading it in an add-on.
A mini simulator window in the corner would be nice too, basically a SinglePlayer server.
Also, auto-enter might be nice : You begin typing a bit of script, and in a window on the right it checks for all functions that have that in their name.
Would be very useful for add-on makers who don't want to have to start a server, see it fail, end server, modify, repeat over and over until it works.
A GUI maker would be quite nice too... i just can't understand all that code about GUIs.