python-varname VS watchpoints

# https://old.reddit.com/r/learnpython/comments/vx8kw0/if_variable_y_within_function_fxy_calls_to/ # Qackydontus.py # https://github.com/pwwang/python-varname # python -m pip install varname from varname import argname def G(z): Name = argname('z') return z, Name def F(x, y): return x, G(y) print(F(1, 2)) # (1, (2, 'y'))

That's possible, but complicated. See this package

It's sad that Python does not really support some of these debugging methods.

E.g. you cannot really watch variable changes. There are some workarounds, like writing a custom __setattr__ or __setattribute__ in case of an object, or checking all STORE_* operations. https://youtrack.jetbrains.com/issue/PY-30387 https://github.com/gaogaotiantian/watchpoints

Reverse debugging is also sth I would like to have, and there are a few projects to support this, but it's not really well supported in standard CPython. https://foss.heptapod.net/pypy/revdb https://pytrace.com/

There is also the watchpoints module to track changes to variables, but I don't think you can use the two of them together since they both use the same underlying callback in Python.

It uses Python's built-in inspect module to get the caller frame. https://github.com/gaogaotiantian/watchpoints/blob/68bc13716...

It then uses sys.settrace (which is intended as an interface for debuggers) to step through the code and check whether the variable has been changed. Documentation on sys.settrace: https://docs.python.org/3/library/sys.html#sys.settrace

Python exposes most of its guts as part of the standard library, making clever hacks like this possible.