builtup4/bu4/parsing/constructs/lnull.py
2021-07-24 15:10:11 +03:00

38 lines
933 B
Python

# Copyright (c) PARRRATE T&V 2021. All rights reserved.
from bu4.evaluation.constructs.enull import ENull
from bu4.evaluation.av.envtype import envtype
from bu4.linking.states.linkingstate import LinkingState
from bu4.parsing.codes import CODE_NULL
from bu4.parsing.constructs.linked import Linked, Parsed
from bu4.linking.states.linkingfinished import LinkingFinished
from bu4.evaluation.constructs.evaluable import Evaluable
__all__ = ('PNull',)
class LNull(Linked):
def __init__(self):
self.future = set()
def link(self) -> LinkingState:
return LinkingFinished(self)
def evaluable(self, env: envtype) -> Evaluable:
return ENull()
def __str__(self):
return '?'
def unlink(self) -> Parsed:
return PNull()
class PNull(Parsed):
def link(self, promise: set[bytes]) -> Linked:
return LNull()
def __bytes__(self):
return bytes([CODE_NULL])