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