On 22.10.2020 04:12, David Mertz wrote: > To bring it back to a concrete idea, here's how I see things: > > 1. The idea of f-string-like assignment targets has little support. Only > Chris, and maybe the OP who seems to have gone away. > 2. The idea of a "scanning language" seems to garner a fair amount of > enthusiasm from everyone who has commented. > 3. Having the scanning language be "inspired by" f-strings seems to fit > nicely > with Python > 4. 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. > 5. 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/ > > 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.
I like this idea :-) There are lots of use cases where regular expressions + subsequent type conversion are just overkill for a small parsing task. The above would fit this space quite nicely, esp. since it already comes with a set of typical format you have to parse, without having to worry about the nitty details (as you have to do with REs) or the type conversion from string to e.g. float. -- Marc-Andre Lemburg eGenix.com Professional Python Services directly from the Experts (#1, Oct 22 2020) >>> Python Projects, Coaching and Support ... https://www.egenix.com/ >>> Python Product Development ... https://consulting.egenix.com/ ________________________________________________________________________ ::: We implement business ideas - efficiently in both time and costs ::: eGenix.com Software, Skills and Services GmbH Pastor-Loeh-Str.48 D-40764 Langenfeld, Germany. CEO Dipl.-Math. Marc-Andre Lemburg Registered at Amtsgericht Duesseldorf: HRB 46611 https://www.egenix.com/company/contact/ https://www.malemburg.com/ _______________________________________________ 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/YD6B2JR7QKVD3MBPQMQQUUROFR7B4AQ2/ Code of Conduct: http://python.org/psf/codeofconduct/
