This is a Game Maker 7.0 Interactive Development Envirnoment (IDE) use to test one or more lines of code easily.
Simply type a line of code in the small box at the bottom and press Enter to run it and print the return value.
You can also use the "print" command to print a value or simple expression, e.g. "print(1+1)" or "print(mouse_x)".
If people find this useful, I will make it easier to create scripts and run multiple lines of code.