Resolving PDDL Parsing Errors in plasp while Successful in Fast Downward

Question

I am working on a PDDL project for a LightsOut game. While my PDDL code executes successfully in Fast Downward, I face parsing errors in the Visual Studio Code PDDL plugin, and plasp is unable to process it correctly.

Here's a part of my PDDL code causing issues:

(define (domain lightsout)
    (:requirements :strips :disjunctive-preconditions :conditional-effects :typing)

    (:types
        light 
    )

    (:predicates
        (on ?l - light) 
        (off ?l - light) 
        (adjacent ?l1 ?l2 - light) 
    )

    (:action toggle
        :parameters (?l - light)
        :precondition (or (on ?l) (off ?l)) 
        :effect (and
            
            (when (on ?l) (and (not (on ?l)) (off ?l)))
            (when (off ?l) (and (not (off ?l)) (on ?l)))
            
            (forall (?adj - light) 
                (when (adjacent ?l ?adj)
                    (and
                        (when (on ?adj) (and (not (on ?adj)) (off ?adj)))
                        (when (off ?adj) (and (not (off ?adj)) (on ?adj)))
                    )
                )
            )
        )
    )
)

The errors reported by the VSC PDDL plugin at line 25 are:

"Syntax error in (and ...)" "Syntax error in action declaration." "Unreadable structure" In addition, plasp is unable to parse this PDDL code. I believe the issue is related to the nested when and forall structures in the action. How can I modify my PDDL code to resolve these parsing errors while maintaining the intended functionality for my game? Are there alternative structures or refactoring techniques I can use to make the code compatible with both the VSC PDDL plugin and plasp?

Any advice or insights to solve these parsing issues would be greatly appreciated.

Answer 1

Split the action into two actions, on's case and off's case? It is probably or that is causing the error.