Hi Todd Thank you for your contribution! I've got a couple of comments. The experts, I hope, will have more to say.
You wrote: > As to why this is useful, the overall problem is that the current logical > operators, like and, or, and not, cannot be overloaded, which means projects > like numpy and SQLAlchemy instead have to (ab)use bitwise operator > There was a proposal to allow overloading boolean operators in Pep-335 [2], > but that PEP was rejected for a variety of very good reasons. The key thing is, I think, the wish for a domain specific language. I find this to be a wholesome wish. But I'd rather create a broad solution, than something that works just for special cases. And if at all possible, implement domain specific languages without extending the syntax and semantics of the language. This would benefit many existing users and projects now, without having to wait for the introduction of a new version of Python, and their project adopting that version. It may help to build on PEP 465 -- A dedicated infix operator for matrix multiplication https://www.python.org/dev/peps/pep-0465/ This addition allows you (from the PEP) to write >>> S = (H @ beta - r).T @ inv(H @ V @ H.T) @ (H @ beta - r) You my want to extend the syntax and semantics so that >>> S = (H @beta - r).T @ inv(H @ V @ H.T) @ (H @beta - r) invokes double-under methods, whose name might be something like __at_beta__ I'm impressed by > https://en.wikipedia.org/wiki/Fluent_interface > https://martinfowler.com/bliki/FluentInterface.html and encourage work on tools for creating such in Python. There is the problem of short-circuiting evaluation, as in the 'and' and 'or' operators (and elsewhere in Python). This has to be a syntax and semantics feature. It can't be controlled by the objects. However, as Steve Dower pointed out last month, we can use lamda for this purpose. I think it's easy to define a function OR such that the following > EXP_1 or EXP_2 >> OR(lambda: EXP_1, lambda:EXP_2) do pretty the same thing (except refactoring the expressions into the lambdas). In fact, I think OR has to be >>> def OR(fn_1, fn_2): ... return fn_1() or fn_2() I hope this help you solve the underlying problems, and have a better time with Python. -- Jonathan _______________________________________________ Python-ideas mailing list Python-ideas@python.org https://mail.python.org/mailman/listinfo/python-ideas Code of Conduct: http://python.org/psf/codeofconduct/
