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

25 lines
690 B
Python

from typing import Mapping, Iterator
from bu4.evaluation.avcontainer import AVContainer
from bu4.evaluation.aftervalue import AfterValue, envtype, Evaluable
class LambdaEnv(Mapping):
def __getitem__(self, k: bytes) -> AfterValue:
if k == self.name:
return self.container
else:
return self.env[k]
def __len__(self) -> int:
return len(self.env) + 1
def __iter__(self) -> Iterator[AfterValue]:
yield self.name
yield from self.env
def __init__(self, env: envtype, name: bytes, evaluable: Evaluable):
self.env = env
self.name = name
self.container = AVContainer(evaluable).after_value