[Tutor] Implementing a MUD engine from scratch

[Christer Enfors]

I'm new to Python, but I've been programming other languages for over 15 
years. Now, I've decided that I want to code my own MUD engine from 
scratch in Python. A MUD is a bit like a MMORPG (like World of 
Warcraft), only it uses text instead of graphics. A MUD is the graphical 
MMORPGs what books are to movies. A MUD acts like a telnet server - you 
use telnet to connect and play. This makes it very easy to try new MUDs; 
unlike graphical MMORPGs, you don't need specific client software for 
each MUD. MUDs are also typically free to play.

To explain more clearly just what it is I want to create, I have to 
explain where I'm coming from. For the past 12 years, I've been playing 
on, and coding with, an existing MUD engine called LPMUD. The LPMUD 
engine itself is coded in C, but it implements a interpreted language 
called LPC. Once you've telnetted to an LPMUD, you can create monsters, 
areas, powers, quests, etc by writing LPC programs. LPC programs can be 
written and edited while the LPMUD is online, so there is no need to 
restart an LPMUD (and thus disconnect all players) to fix coding errors 
or add new game content. LPC is also inherently sandboxed, so a 
malevolent coder can't affect filesystems outside of the dedicated LPMUD 
directory, and so on.

I want to make something similar in Python. Like I said, the LPMUD 
engine is coded in C, but uses the LPC language to create the actual 
game content. I my case, Python will be used for both purposes.

Now on to my actual questions:

1) I want to be able to update parts of the code (the game content) 
while the MUD (the engine) is running. Errors in the game shouldn't stop 
the entire MUD - I guess I should use exceptions for this? Any pointers 
as to where I should begin to research how to accomplish this? I'm 
guessing that perhaps IDLE could be worth a look (since it is a Python 
program that allows you to edit and run Python programs inside it).

2) Would it be realistically possible to sandbox my MUD, so that 
arbitrary Python programs (written by appointed MUD staff) can't affect 
the hosting machine?

Thanks in advance.

-- 
Christer Enfors