game engine (as in rules not graphics)

[Aaron Brady]

On Dec 29, 4:14 am, Martin <mar... at marcher.name> wrote:
> Hi,
>
> 2008/12/29 Phil Runciman <ph... at aspexconsulting.co.nz>:
>
> > See: Chris Moss, Prolog++: The Power of Object-Oriented and Logic Programming (ISBN 0201565072)
>
> > This book is a pretty handy intro to an OO version Prolog produced by Logic Programming Associates.
> > From: Aaron Brady [mailto:castiro... at gmail.com]
> > Sent: Sunday, 28 December 2008 1:22 p.m.
> > Not my expertise but here are my $0.02.  You are looking for ways to represent rules: buying a house is legal in such and such situation, and the formula for calculating its price is something.  You want "predicates" such as InJail, OwnedBy, Costs.
>
> > Costs( New York Ave, 200 )
> > InJail( player2 )
> > OwnedBy( St. Charles Ave, player4 )
> > LegalMove( rolldie )
> > LegalMove( sellhouse )
>
> I'm not sure I'm looking for prolog, i had an introductory course back
> at the university but it didn't exactly like it. I'm after some info
> how such rules would defined in python (specifically python althou
> logic programming is probably the more appropriate way).
>
> I guess I'm missing quite some basics in the design of such concepts,
> I'll head back to google to find some introductory stuff now :).
snip

It depends on what you want to do with it.  Do you want to answer a
question about whether something is legal?  Do you want a catalog of
legal moves?  Do you want to forward-chain moves to a state?  Do you
want just a representation for its own sake?

For instance, the game just started.  Player 1 landed on Oriental,
bought it, and Player 2 landed in the same place.  Here are the legal
possibilities.

Player 1 offers to sell Oriental to Player X.
Player X offers to buy Oriental from Player 1.
Player 1 mortgages Oriental.
Player 1 collects rent from Player 2.
Player 3 rolls dice.

Thinking aloud, I think the closest thing to predicates you'll have in
Python is to build a Relation class or use a relational database.
Some tables you might use are: Property( id, name, price, rent0houses,
rent1house, ..., numhouses, mortgaged, owner ).  Player( id, location,
money ).  LastMove( player.id ).

P.S.  There is 'pyprolog' on sourceforge; I did not check it out.