On Tuesday, November 29, 2016, Wes Turner <wes.turner@gmail.com> wrote:
The existing docs for errors and exceptions:
- https://docs.python.org/2/library/exceptions.html - https://docs.python.org/3/library/exceptions.html - https://hg.python.org/cpython/file/tip/Doc/library/exceptions.rst - https://github.com/python/cpython/blob/master/Doc/library/exceptions.rst
- https://docs.python.org/2/tutorial/errors.html - https://docs.python.org/3/tutorial/errors.html - https://hg.python.org/cpython/file/tip/Doc/tutorial/errors.rst - https://github.com/python/cpython/blob/master/Doc/tutorial/errors.rst
- https://www.tutorialspoint.com/python/python_exceptions.htm
- If the docs don't answer the question (and match to the search terms), they probably should.
- [ ] DOC: something about why "except Exception: pass" is usually bad - [ ] DOC: something about SystemExit and atexit: https://docs.python. org/2/library/atexit.html
You can get alot more traceback from pytest (w/ pytest-sugar) and/or nose (with nose-progressive).
There is extra information in the stack at exception time; but, IIUC, it would take a number of subclasses with class-specific docs and/or class introspection to be as detailed as "you probably wanted .append there because this is a List and the length is n but the key was".
Maybe a "learning mode" which automatically calls inspect.getdoc() on Exception would be useful (sys.excepthook)? Practically, I usually just open an extra IPython shell and run `list.append?` for docs or `list.append??` for (Python but not C!) source (inspect.getsource). IPython also prints the function signature with `?`
- [ ] How could I also print out type annotations w/ function signatures and docstrings?/??/??? https://github.com/python/typeshed/blob/master/stdlib/2/typing.pyi
The pdb++ debugger requires funcsigs in order to print function signatures. If pdb++ is installed, it preempts the standard pdb module; so `nosetests --pdb` and `pytest --pdb` launch pdb++ when an error or exception is raised.
https://pypi.python.org/pypi/pdbpp/
http://nose.readthedocs.io/en/latest/plugins/debug.html
http://doc.pytest.org/en/latest/usage.html
https://docs.python.org/2/library/inspect.html
Exceptions could be better someday. Testing (and debugging) skills are always good to learn; coincidentally, there are many great tools for it.
... https://westurner.org/wiki/awesome-python-testing#debugging
On Tuesday, November 29, 2016, Victor Stinner <victor.stinner@gmail.com <javascript:_e(%7B%7D,'cvml','victor.stinner@gmail.com');>> wrote:
Hi,
Python is optimized for performance. Formatting an error message has a cost on performances.
I suggest you to teach your student to use the REPL and use a custom exception handler: sys.excepthook: https://docs.python.org/2/library/sys.html#sys.excepthook
Using a custom exception handler, you can run expensive functions, like the feature: "suggest len when length is used".
The problem is then when students have to use a Python without the custom exception handler.
Victor _______________________________________________ Python-ideas mailing list Python-ideas@python.org https://mail.python.org/mailman/listinfo/python-ideas Code of Conduct: http://python.org/psf/codeofconduct/