PyConstants/pyconstants.py

34 lines
1.1 KiB
Python

import sys
from collections import defaultdict
from typing import Dict, Callable, List, Final
from dataclasses import dataclass
FRAMETYPE = object
@dataclass
class ConstantValue:
frame: FRAMETYPE # FIXME
name: str
value: object
def _traceFun(frame: FRAMETYPE, event: str, arg: object) -> None: # FIXME
for constant in constMap[frame]:
if constant.name in frame.f_locals and frame.f_locals[constant.name] != constant.value:
frame.f_locals[constant.name] = constant.value
raise SyntaxError(f"Cannot assign value to constant {repr(constant.name)}")
class _ConstClass:
def __setattr__(self, name, value):
"""This is the method called when a new constant is created"""
targetFrame = sys._getframe(1)
targetFrame.f_trace_lines = False
targetFrame.f_trace_opcodes = True
targetFrame.f_trace = _traceFun
targetFrame.f_locals[name] = value
constMap[targetFrame].append(ConstantValue(targetFrame, name, value))
constMap: Dict[FRAMETYPE, List[ConstantValue]] = defaultdict(list) # FIXME
sys.settrace(lambda frame, event, arg: None)
const = _ConstClass()