Effects 'When' and 'ForAll' lack instantiate method

[Jeffjewett27]

Subject of the issue

The recent action instantiation feature (#158) is useful. However, the current implementation fails for actions with a (forall ...) effect.

'Forall' object has no attribute 'instantiate'
  File "/home/jjewett/miniforge3/envs/skillet/lib/python3.11/site-packages/pddl/action.py", line 93, in instantiate
    effect=self.effect.instantiate(instantiation) if self.effect else None,
           ^^^^^^^^^^^^^^^^^^^^^^^
  File "/home/jjewett/project/embodied-repair/conditional_repair/.dev/fastd.py", line 21, in <module>
    grounded = action.instantiate([obj])
               ^^^^^^^^^^^^^^^^^^^^^^^^^

This is because pddl.logic.effects.ForAll is treated as a Formula in action.effect, but does not implement instantiate.

>>> action.effect.__repr__
'Forall(frozenset({Variable(p)}), (friendly ?o ?p))'

Your environment

• OS: Ubuntu 24.04
• Python version: 3.11.14
• Package Version 0.4.5

Steps to reproduce

(define (domain hello-world)
  (:requirements :typing :conditional-effects )
  (:predicates
    (hello-said)
    (friendly ?o ?p)
  )

  ; This action changes the state from not said to said
  (:action say-hello
    :parameters (?o)
    :precondition (and )
    :effect (and (forall (?p) (friendly ?o ?p)))
  )
)

(define (problem hello-world-problem)
 (:domain hello-world)
 (:objects
   o1 p1 p2 - object
 )
 (:init

 )
 (:goal (friendly o1 p1)
 )
)

domain = DomainParser()(domain_str)
problem = ProblemParser()(problem_str)

obj = next(iter(problem.objects))
action = next(iter(domain.actions))
grounded = action.instantiate([obj])

Expected behaviour

It should not error out. ForAll should instantiate its effect. When should instantiate its condition and effect.

Actual behaviour

pddl.logic.effects.ForAll gives the error showed above.

pddl.logic.effects.When gives a similar error.