Develop a Library of Problem Generators

[gfrances]

I should find time to port to Tarski some of the countless problem generators that I have written for different papers / projects. Having some generators submodule (again, no need for that to live under this repo) that is basically a user module of Tarski and its io module and provides off-the-shelf generators for standard problems (blocksworld, gripper, and so on) would be a great way of showcasing the capabilities of Tarski (in fact the change from my old python generator scripts to developing generators using Tarski has really saved me a lot of time), and eventually of having a good library of problem generators that fosters collaboration from the community, etc.

[miquelramirez]

I think this is a great idea - it would have certainly helped @emilkeyder quite a bit. I guess it is possible to have different pip packages correspoding to submodules (which we can then easily install with pip when needed).

[emilkeyder]

I think it would also be really nice to be able to automatically add common objects/attributes like counts (next ?c1 ?c2, less-than ?c1 ?c2, etc) and location graphs (adjacent ?x ?y, agent-at ?x). Doing that in a generic way that's easy to understand and write probably requires more thought though.

[miquelramirez]

We could have special theories like ORDERED_SET and GRAPHS, defining predicates like that (and some helpful default sorts too).

One issue with the latter is that we dropped support for sorts (types) being defined as subsets of more than one sort (type) - i.e. there's no multiple inheritance in tarski. That complicate some of the "idioms" you can see in the IPC where multiple types are used to tag objects and help the grounding process to produce succinct representations.