On Thu, 22 Oct 2020 at 03:16, David Mertz <me...@gnosis.cx> wrote: > > To bring it back to a concrete idea, here's how I see things: > > The idea of f-string-like assignment targets has little support. Only Chris, > and maybe the OP who seems to have gone away. > The idea of a "scanning language" seems to garner a fair amount of enthusiasm > from everyone who has commented. > Having the scanning language be "inspired by" f-strings seems to fit nicely > with Python > Lots of folks like C scanf() as another inspiration for the need. I was not > being sarcastic in saying that I thought COBOL PICTURE clauses are another > similar useful case. I think Perl 6 "rules" were trying to do something > along those lines... but, well, Perl.
There's also SNOBOL (and Icon) matching functions, although they are less of a pattern "language" and more of a set of building blocks for making matchers. > In my opinion, this is naturally a function, or several related functions, > not new syntax (I think Steven agrees) > > So the question is, what should the scanning language look like? Another > question is: "Does this already exist?" > > I'm looking around PyPI, and I see this that looks vaguely along the same > lines. But most likely I am missing things: https://pypi.org/project/rebulk/ The other one I know of (mentioned previously somewhere in all of this) is https://pypi.org/project/parse/ > > In terms of API, assuming functions, I think there are two basic models. We > could have two (or more) functions that were related though: > > # E.g. pat_with_names = "{foo:f}/{bar:4s}/{baz:3d}" > matches = scan_to_obj(pat_with_names, haystack) > # something like (different match objects are possible choices, dict, > dataclass, etc) > print(matches.foo) > print(maches['bar']) > > Alternately: > > # pat_only = "{:f}/{:4s}/{:3d}" > foo, bar, baz = scan_to_tuple(pat_only, haystack) > # names, if bound, have the types indicated by scanning language > > There are questions open about partial matching, defaults, exceptions to > raise, etc. But the general utility of something along those lines seems > roughly consensus. Agreed Paul _______________________________________________ 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/N4HFLC6J5R47GXOTKLW4KY546MR5QTVK/ Code of Conduct: http://python.org/psf/codeofconduct/
