Use `raise XslxValueError` and other error handling improvements

[cnpryer]

fixes #233 by

• [x] replacing eprint calls with direct XlsxValueError raises
• [x] use sys.exit directly

[cnpryer]

what if we did a little more and also replaced eprint with raisees where eprint was called and where sys.stderr.write is called? https://github.com/dilshod/xlsx2csv/blob/ee4d40cf543903a44083a92c97a1912af719ff0e/xlsx2csv.py#L1118

edit: added to the PR (see above)

[cnpryer]

@ghuls! You're the best. Thanks for the pointers.

Now that I'm curious, is it more ideal to use sys.stderr.write + a sys.exit or should this just throw a sys.exit?

https://docs.python.org/3/library/sys.html#sys.exit

[ghuls]

@ghuls! You're the best. Thanks for the pointers.

Now that I'm curious, is it more ideal to use sys.stderr.write + a sys.exit or should this just throw a sys.exit?

https://docs.python.org/3/library/sys.html#sys.exit

Seems like sys.exit is viable for writing the error message.

[cnpryer]

What about this guy under the main https://github.com/dilshod/xlsx2csv/blob/ee4d40cf543903a44083a92c97a1912af719ff0e/xlsx2csv.py#L1205

[ghuls]

It should be hanlded by: https://github.com/dilshod/xlsx2csv/blob/ee4d40cf543903a44083a92c97a1912af719ff0e/xlsx2csv.py#L1205 , but could also be handled explicitly.

This should also raise a InvalidXlsxFileException exception: https://github.com/dilshod/xlsx2csv/blob/ee4d40cf543903a44083a92c97a1912af719ff0e/xlsx2csv.py#L1039

[dilshod]

It seems good