Oscar Benjamin writes: > On Fri, 26 Feb 2021 at 02:49, Stephen J. Turnbull > <turnbull.stephen...@u.tsukuba.ac.jp> wrote:
> > Thing is, this "mutual inclusion" condition isn't really about parsing > > (ie, syntax)[1]; this is about semantics -- like all input validation. > > I don't object to having it in argparse, but it's going to be so > > domain-dependent that I don't think we should do more than provide > > hooks to validate individual arguments (eg, a 0 <= p <= 1 constraint > > on probabilities or proportions), and an args.validate hook to do > > cross-argument validation. > > Given that the hook would just be called after parsing the args would > be the advantage of using a hook compared to just validating the args > yourself after calling parse_args? "Quis custodiat ipsos custodes?" That is, it has no extra value in validating the args, but by providing a standard place to put validation code, it helps us to validate the validators. For most of my scripts, I'm not going to write *any* command line validation code, but for programs called by other tools, I think it would be helpful to me to have all command line validation in one standard place. We could even have a tool in argparse to report which arguments have validators and which don't, though that smells like overkill (and I myself would probably write it as a search in Emacs Lisp rather than use an argparse-provided tool). _______________________________________________ Python-ideas mailing list -- python-ideas@python.org To unsubscribe send an email to python-ideas-le...@python.org https://mail.python.org/mailman3/lists/python-ideas.python.org/ Message archived at https://mail.python.org/archives/list/python-ideas@python.org/message/A22OJJSJOZ33ITLOBXLASK37LU3IB67Y/ Code of Conduct: http://python.org/psf/codeofconduct/
