#  Copyright (c) PARRRATE T&V 2021. All rights reserved.

from bu4.evaluation.av.envtype import envtype
from bu4.evaluation.constructs.enull import ENull
from bu4.evaluation.constructs.evaluable import Evaluable
from bu4.linking.constructs.linked import Linked

__all__ = ('LNull',)


class LNull(Linked):
    def __init__(self):
        self.future = set()

    def evaluable(self, env: envtype) -> Evaluable:
        return ENull()

    def __str__(self):
        return '?'