Three-ish questions: 1. What could this do that Macropy does not already do? (yes, I know "run as top-level script", but that's uninspiring for me).
2. Do you have any evidence Numba developers would actually want this?! (as claimed in draft FAQ). I know a lot of them, and teach Numba sometimes, although have not directly contributed. I do not believe they would prefer the AST to the bytecode for the analysis. 3. I guess not really a question, but I just can't see a language feature like this as fully "opt-in". Any feature that is added is going to occur in code I wind up having to maintain. That's already a pain point with e.g. metaclasses/decorators, monkey patching, and other constructs, where code often doesn't mean what it *looks like* it would mean. ... macros, even if hygienic, seem to make that need to learn a new DSL or language for every code base much worse than those other constructs. Looking at code with entirely novel flow control constructs adds a lot of cognitive burden. Not least because there are likely to be a hundred different implementations that make "case" or "do until" do very subtly different things in each one. On Tue, Sep 15, 2020 at 9:27 AM Mark Shannon <m...@hotpy.org> wrote: > > Hi all, > > I'd like to propose a new PEP for hygienic macros. > > I'm attempting to reduce the controversy and pain of adding new syntax > to Python, > ... by adding new syntax. > > That might sound silly, but I hope to persuade that it isn't. > > Adding a new feature to the language is always controversial. > > Before a new module or functionality is added to the standard library, > it must usually prove itself as a package on PyPI. > > (Not always the same package, the value of dataclasses was demonstrated > by "attrs".) > > However, this isn't currently possible with new language features. > > Any new language feature has pros and cons. > It adds expressive power for some (usually experienced) users, > but potentially confuses and inconveniences other users (especially > beginners). > However, it is very hard, if not impossible, to determine whether adding > new syntax will be be beneficial or harmful before the syntax is added. > > Is there a way to add new syntax in a way that allows it be battle > tested before adding to the released version of the language? > Yes there is, Macros. > > I'm not talking about C-style macros which do textual substitution, but > "hygienic" macros that rewrite the AST during compilation. > > Macros allow domain specific new syntactic features, without bloating > the language or confusing newcomers. > > In general, I would except macros to be used within libraries, so that > those libraries gain the power of their custom macros without making > Python ever larger and more complex. > > However, there is no reason why they cannot be made more widely > available. Should a macro become widely used and popular, then it can be > considered for adoption into the language. > > The PEP: > > https://github.com/markshannon/peps/blob/hygenic-macros/pep-0700.rst > > > Cheers, > Mark. > _______________________________________________ > Python-Dev mailing list -- python-dev@python.org > To unsubscribe send an email to python-dev-le...@python.org > https://mail.python.org/mailman3/lists/python-dev.python.org/ > Message archived at > https://mail.python.org/archives/list/python-dev@python.org/message/7BX4S6ROKPMTTJR64UPRJ4D66C23HMHI/ > Code of Conduct: http://python.org/psf/codeofconduct/ > -- The dead increasingly dominate and strangle both the living and the not-yet born. Vampiric capital and undead corporate persons abuse the lives and control the thoughts of homo faber. Ideas, once born, become abortifacients against new conceptions.
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