You then override the function which calculates the price a character will get for an object, and insert an if-check for your race, doubling the price. Now type test, followed by some string. The command interpreter, after trying the MUD created commands, will try to find a command in your personal home directory. This would be e.g. The .arc file contains a class definition .
Compilation is the process in which the raw text is turned into actual machine code.
At that point, all syntax errors are found. Once the class has been compiled once, it does not have to be compiled again until it's changed. After the class is compiled, the MUD creates an object of that class. This is in this case done only once, just after the command is first compiled. Finally, the command is executed.