On 5 January 2018 at 16:28, Steve Barnes <gadgetst...@live.co.uk> wrote: > Currently invoking `python -c "some;separated;set of commands;"` will, > if you need to use any library functions, require one or more import > somelib; sections in the execution string. This results in rather > complex "one liners". > > On the other hand `python -m somelib` will load somelib and attempt to > execute its `__main__()` or give an error if there isn't one.
That's not quite how the -m switch works, but that doesn't affect your core point: "-m somemodule" terminates the option list and defines what will be run as `__main__`, so you can't compose it with other options (like `-c`). > What I would like to suggest is a mechanism to pre-load libraries before > evaluating the -c option as this would allow the use of code from > libraries that don't have a `__main__` function, or those that do but it > doesn't do what you want. This could be an interesting alternative to the old "python -C" idea in https://bugs.python.org/issue14803 (which suggests adding an alternative to "-c" that runs the given code *before* running `__main__`, rather than running it *as* `__main__`). To summarise some of the use cases from that discussion: * setting `__main__.__requires__` to change how `import pkg_resources` selects default package versions * reducing the proliferation of `-X` options to enable modules like tracemalloc and faulthandler * providing a way to enable code coverage as early as possible on startup (and have the setting be inherited by subprocesses) The main downside I'd see compared to that `python -C` and PYTHONRUNFIRST idea is that it might encourage the definition of modules with side-effects in order to use it to reconfigure the interpreter at startup. That concern could potentially be mitigated if we did both: * -M/PYTHONIMPORTFIRST: implicit imports in __main__ on startup * -C/PYTHONRUNFIRST: code to run in __main__ on startup (after the implicit imports) However, the issue then is that "python -M numpy" would just be a less flexible alternative to a command like "python -C 'import numpy as np'". Cheers, Nick. -- Nick Coghlan | ncogh...@gmail.com | Brisbane, Australia _______________________________________________ Python-ideas mailing list Python-ideas@python.org https://mail.python.org/mailman/listinfo/python-ideas Code of Conduct: http://python.org/psf/codeofconduct/
