search.jshop

(defdomain search (

  (:operator (!move ?agent ?from ?to)
    (
      (at ?agent ?from)
      (adjacent ?from ?to)
    )
    ((at ?agent ?from))
    ((at ?agent ?to))
  )

  (:operator (!!visit ?agent ?pos)
    ()
    ()
    ((visited ?agent ?pos))
  )

  (:operator (!!unvisit ?agent ?pos)
    ()
    ((visited ?agent ?pos))
    ()
  )

  (:method (forward ?agent ?goal)
    base
    ((at ?agent ?goal))
    ()

    recursion
    (
      (at ?agent ?from)
      (adjacent ?from ?place)
      (not (visited ?agent ?place))
    )
    (
      (!move ?agent ?from ?place)
      (!!visit ?agent ?from)
      (forward ?agent ?goal)
      (!!unvisit ?agent ?from)
    )
  )

  (:method (backward ?agent ?goal)
    base
    ((at ?agent ?goal))
    ()

    recursion
    (
      (adjacent ?place ?goal)
      (not (visited ?agent ?place))
    )
    (
      (!!visit ?agent ?goal)
      (backward ?agent ?place)
      (!move ?agent ?place ?goal)
      (!!unvisit ?agent ?goal)
    )
  )

  (:method (bidirectional_forward ?agent ?goal)
    base
    ((at ?agent ?goal))
    ()

    recursion
    (
      (at ?agent ?from)
      (adjacent ?from ?place)
      (not (visited ?agent ?place))
    )
    (
      (!move ?agent ?from ?place)
      (!!visit ?agent ?from)
      (bidirectional_backward ?agent ?goal)
      (!!unvisit ?agent ?from)
    )
  )

  (:method (bidirectional_backward ?agent ?goal)
    base
    ((at ?agent ?goal))
    ()

    recursion
    (
      (adjacent ?place ?goal)
      (not (visited ?agent ?place))
    )
    (
      (!!visit ?agent ?goal)
      (bidirectional_forward ?agent ?place)
      (!move ?agent ?place ?goal)
      (!!unvisit ?agent ?goal)
    )
  )

  ; This method is beyond JSHOP definition
  (:method (meta ?search ?predicate ?agent ?goal)
    base
    ((?predicate ?agent ?goal))
    ()

    recursion
    ()
    (
      (?search ?agent ?goal)
    )
  )
))