[kasbah]

To me the interesting thing is the logic programming "rules" and their overlap with game rules. Inspired by work at Stanford on the logic programming based Game Description Language [1] I implemented Tic Tac Toe in Datascript yesterday: https://github.com/kasbah/datascript-games/blob/e06a37025bf9...

I am still not clear whether there isn't a more succinct rule definition than what I have there. In the Stanford paper you have rules like:

   (<= (column ?n ?x)
     (true (cell 1 ?n ?x))
     (true (cell 2 ?n ?x))
     (true (cell 3 ?n ?x)))

But in Datascript I have to do much more rigmarole around shuffling the data around:

  [(column ?n ?x) 
    [?current "ident" "current"] 
    [?coord0 "type" "coord"] 
    [?coord1 "type" "coord"] 
    [?coord2 "type" "coord"]
    [?coord0 "m" 0] 
    [?coord1 "m" 1] 
    [?coord2 "m" 2] 
    [?coord0 "n" ?n] 
    [?coord1 "n" ?n] 
    [?coord2 "n" ?n] 
    [?coord0 "name" ?key0] [?current ?key0 ?x]
    [?coord1 "name" ?key1] [?current ?key1 ?x]
    [?coord2 "name" ?key2] [?current ?key2 ?x]]

I don't know if this is down to Datascript/Datomic Datalog limitations or more the limitations of my understanding.

How do you approach your experiments? If you have any of your work to share or some tips on what I am doing I'd be very interested.

[1]: https://www.cs.uic.edu/~hinrichs/papers/love2006general.pdf

[refset]

This is a consequence of the Datomic information model which is focused on handling a single universe of triples (to facilitate natural schema growth) instead of independent n-ary relations. However unlike when building serious business applications, for most simple games you probably won't ever care about the ease of handling the schema growth of persisted data. You would likely care more once you think about supporting long-lived multiplayer environments or introducing played-defined concepts within the game.

[kasbah]

Interesting, thanks. I am especially interested in the idea of introducing player-defined concepts.

Would you be able to recommend a Datalog implementation that allows independant n-ary relations. Ideally one I can use from Python or Javascript in a sort of sandboxed way, as I am doing with Datascript, but if you have any recommendation at all it would be helpful to me.

[refset]

DataScript already supports processing n-ary relations, it's just not how the data is naturally stored when you use `d/transact!`. Even though it's all in-memory anyway (ignoring the recent addition of durable storage on the JVM) the main benefit you get when 'storing' data is the suite of persistent B-Tree EAVT indexes. DataScript also let's you store plain vectors (and most other objects) as values, which you can access from the Datalog, so it's very flexible really. And learning Clojure is good fun.

If you want to try something more exotic I would be tempted by https://logica.dev/ + some flavour of SQLite (potentially in-memory/WASM).