builtup4/bu4/parsing/lnull.py
2021-07-24 02:34:37 +03:00

34 lines
759 B
Python

from bu4.evaluation.enull import ENull
from bu4.codes import CODE_NULL
from bu4.parsing.linked import Linked, LinkingState, Parsed
from bu4.linking.linkingfinished import LinkingFinished
from bu4.evaluation.aftervalue import envtype, Evaluable
__all__ = ('LNull', '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])