On 18 January 2018 at 07:46, Steven D'Aprano <st...@pearwood.info> wrote: > To justify a keyword, it needs to do something special that a built-in > function can't do, like delayed evaluation (without wrapping the > expression in a function).
My reaction to these threads for a while has been "We should just add a function for unconditional assertions in expression form", and I finally got around to posting that to the issue tracker rather than leaving it solely in mailing list posts: https://bugs.python.org/issue32590 The gist of the idea is to add a new ensure() builtin along the lines of: class ValidationError(AssertionError): pass _MISSING = object() def ensure(condition, msg=_MISSING, exc_type=ValidationError): if not condition: if msg is _MISSING: msg = condition raise exc_type(msg) There's no need to involve the compiler if you're never going to optimise the code out, and code-rewriters like the one in pytest can be taught to recognise "ensure(condition)" as being comparable to an assert statement. Cheers, Nick. -- Nick Coghlan | ncogh...@gmail.com | Brisbane, Australia _______________________________________________ Python-ideas mailing list Python-ideas@python.org https://mail.python.org/mailman/listinfo/python-ideas Code of Conduct: http://python.org/psf/codeofconduct/
