IPP Homepage: old syntax

Syntax and Semantics of Fact Files for IP² 1.0 and 2.0

The fact file contains all the typed objects of the domain as well as the initial and the goal state. It must be a text file of the form (name).fct . As in the .ops file, you need to put different problems into different files.

Here's an EBNF for the .fct file:

  FCT_FILE       ::=  TYPE_LIST

                      "initial:" CONST_LIT_LIST ";"

                      "goal:" CONST_LIT_LIST ";"

  TYPE_LIST      ::=  TYPE  |  TYPE TYPE_LIST

  TYPE           ::=  NAME ":" CONSTANT_LIST ";"

  CONSTANT_LIST  ::=  NAME | NAME SPC CONSTANT_LIST

  CONST_LIT_LIST ::=  CONST_LIT  |  CONST_LIT CONST_LIT_LIST

  CONST_LIT      ::=  NAME "("  {  NAME  }  ")"


  NAME           ::=  small_letter  {  small_letter  |  "-"  |  digit  }

  SPC            ::=  " "  {  " "  |  newline  }

TYPE stands for a list of constants of the same type, for example

location: freiburg melbourne cairo;

CONST_LIT_LIST stands for a list of ground atoms (facts): on(b1 table) arm-empty()

An example for a legal IP² fact file is:

  location: l1 l2 l3 home;
  object: o1 o2 o3;

  initial: is-at(home) at(o1 l1) at(o2 l2) at(o3 l3) 
           not-in(o1) not-in(o2) not-in(o3);

  goal: is-at(home)  at(o1 home) at(o2 home) at(o3 home);

NOTE:

We have skipped the LISP-oriented representation of facts and returned to a more logic-oriented one with the difference that the parameters of a predicate are not separated by commas, but space.
In case that you do not have any types in your planning problem, which implicitely requires that all operators must be ground, simply start the file with the initial and goal state specification.
If you have a literal without any parameters, you still have to add the "()", as in arm-empty().
An object can have several types, i.e., it can appear in more than one TYPE definition, cf. the next example. We do not pose any restrictions on the type hierarchy.
You should put objects of the same type into one single type declaration. Note the ";" that ends all entries including the state specifications.

This is the .fct file used for Russell's flat tire domain:


object: wrench jack pump wheel1 wheel2 nuts; 
hub: the-hub; 
nut: nuts;
container: boot;
wheel: wheel1 wheel2; 

initial: 

intact(wheel2) in(jack boot) in(pump boot) have(wheel2) 
in(wrench boot) on(wheel1 the-hub) on-ground(the-hub) tight(nuts the-hub)
not-inflated(wheel2) unlocked(boot) fastened(the-hub) closed(boot);

goal:
 
on(wheel2 the-hub) inflated(wheel2)
in(wheel1 boot)
in(wrench boot) in(jack boot) in(pump boot) 
tight(nuts the-hub) 
closed(boot);

Note that wheel1 and wheel2 have two different types; this makes it possible to treat them as objects when applying the put-in, put-out ( of boot ) operators and to distinguish them from other objects when applying the put-on-wheel or remove-wheel operators.

As in .ops files, space and newlines can be inserted wherever you like, except, of course, in names.
comments go from "#" to newline.

Important: Do not use Tabulator signs, they cause syntax errors.

Syntax and Semantics of Fact Files for IP2 1.0 and 2.0

Syntax and Semantics of Fact Files for IP² 1.0 and 2.0