todo: failing to parse tetris
Closed this issue · 4 comments
While parsing the domain file, it fails to recognize an implied type "pieces"
This is one of those things where people don't agree what is or is not correct in :types specifications. We had many discussions about these, including things like
non-unique supertypes:
(:types
b c - object
a - c
a - b)
cyclic specs:
(:types
a - b
b - a)
self-referential specs:
(:types a - a)
Pyperplan follows the semantics that all types other than the universal supertype object (which is mentioned as such in the PDDL 1.2 paper) need to be explicitly introduced. When I researched this a long time ago, I think this was the semantics that Drew McDermott's type library actually used, but I could never get 100% confirmation of this.
Long story short, there is no agreement on what the semantics of types should be, and so whatever semantics pyperplan picks, someone would be unhappy with it. :-(
I am somewhat reluctant to change the semantics, but we could for example add an FAQ item or something similar. What do people think?
Adding a short FAQ item (to the README?) sounds like a good idea.
Are you willing to take this on, Jendrik?
I copied your main sentence to the README: ec559e8