I am not enthusiastic about this idea at all: as I perceive it it is an IDE problem, external to the language, and should be resolved there - maybe with a recommendation PEP.
But on the other hand, I had seem tens of e-mails discussing string-subclassing, so that annotations could suffice as a hint to inner-string highlighting - and then: subclassing is not really needed at all: Maybe we can allow string tagging in annotations by using `str['html']`, "str['css']" and so on. (the typing module even could take no-op names such as "html", "css", etc... to mean those without any other signs, so stuff could be annotated like `template: html = "xxxx"` which the the same typing machinery that makes things like `TypedDict`. `Required`, etc... work would present these as plain "str" to the runtime, while allowing any tooling to perceive it as a specialized class. In other words, one could then either write: mytemplate: str['html'] = "<html> ....</html>" Or from typing import html mytemplate: html = ... (the former way could be used for arbitrary tagging as proposed by the O.P. , and it would be trivial to add a "register" function to declaratively create new tags at static-analysis time. This syntax has the benefits that static type checkers can take full-beneffit of the string subtypes, correctly pointing out when a "CSS" string is passed as an argument that should contain "HTML", with no drawbacks, no syntax changes, and no backwards compatibility breaks. On Thu, Dec 22, 2022 at 1:42 AM Christopher Barker <python...@gmail.com> wrote: > > On Wed, Dec 21, 2022 at 9:35 AM Chris Angelico <ros...@gmail.com> wrote: > >> >From the look of things, PyUnicode_Join (the internal function that >> handles str.join()) uses a lot of "reaching into the data structure" >> operations for efficiency. It uses PyUnicode_Check (aka "isinstance(x, >> str)") rather than PyUnicode_CheckExact (aka "type(x) is str") and >> then proceeds to cast the pointer and directly inspect its members. >> >> As such, I don't think UserString can ever truly be a str, > > > I had figured subclasses of str wouldn’t be full players in the C code — > but join() us pretty fundamental:-( > > -CHB > -- > Christopher Barker, PhD (Chris) > > Python Language Consulting > - Teaching > - Scientific Software Development > - Desktop GUI and Web Development > - wxPython, numpy, scipy, Cython > _______________________________________________ > 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/C2HG3QJOU5SLU536CGOJ26VKXVEBZYBH/ > Code of Conduct: http://python.org/psf/codeofconduct/ >
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