Re: [pygame] Ridiculously simple way to seperate game-object code

[Kris Schnee <kschnee@xxxxxxxxxx>]

James Hofmann wrote:
> http://people.ucsc.edu/~jhofmann/programmables.py
>
> More "inspired by Megazeux" code.

Neat. I remember that in Megazeux the game's "objects" were actual 
things with a location in the game world, to the extent that if you 
wanted a "global function" you'd probably end up putting it inside a 
fake wall in the corner. Programs had ways of interacting that included 
traditional message-passing and physical action; eg. Robot A could 
respond to being shot, and B could shoot to get A to react!

Doesn't Python have a "compile" function that turns a complex statement 
into an executable code block? Something like that could be used for 
if-branches and the like. So could a kludge like turning if/then 
branches into GOTO statements; this could be done by some quick run-time 
parsing, eg:

if health < max_health:
    Cast("Heal")
else:
    Attack()

becomes at run-time something like:

switch( (health < max_health) )
IF:
    Cast("Heal")
ELSE:
    Attack()

...where switch is basically the goto function, and takes up a cycle. I 
can think of variations on this. The point is that you'd have a way to 
treat the if statement as a single statement by itself, and handle the 
resulting branches in seperate cycles.

I'd like to see this hooked up to some standard functions for 
interacting with a game world. When I work again on my tile engine I 
might include support for something like this.

As for security, you probably won't be able to make it perfect, but you 
can easily provide a first line of defense by doing a TestForEvil() 
function on each line before executing it, eg. "skip_line = False. for 
command in FORBIDDEN_COMMANDS: if command in line_to_be_executed: 
skip_line = True; print 'Hacker alert!'" You could also scan the whole 
program in advance for greater efficiency, but since this code would let 
a program change its own code while running (!), there's a big security 
hole there.

Kris