game engine (as in rules not graphics)

[Aaron Brady]

On Dec 29 2008, 8:52 am, Aaron Brady <castiro... at gmail.com> wrote:
> 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.

You know what I am thinking for this-- not that the OP is still
around-- is a regular expression / BNF grammar that transitions on
moves from one legal set of moves to the next.  It will need some sort
of concatenation structure, since late in the game, selling each
property a player has is a legal move.  Sorry for the replies to
myself.