On Mon, Sep 13, 2021 at 1:37 AM Serhiy Storchaka <storch...@gmail.com> wrote: > > 12.09.21 17:28, Guido van Rossum пише: > > This is cool. > > > > AFAIK pytest does something like this. How does your implementation differ? > > What pytest does is awesome. I though about implementing it in the > standard compiler since seen it the first time. > > > What is your argument for making this part of the language? Why not a > > 3rd party library? > > It needs a support in the compiler. The condition expression should be > compiled to keep all immediate results of subexpressions on the stack. > If the final result is true, immediate results are dropped. If it is > false, the second argument of assert is evaluated and its value together > with all immediate results of the first expression, together with > references to corresponding subexpressions (as strings, ranges or AST > nodes) are passed to the special handler. That handler can be > implemented in a third-party library, because formatting and outputting > a report is a complex task. The default handler can just raise an > AttributeError. >
I wonder, could this be simplified a bit, on the assumption that a well-written assertion shouldn't have a problem with being executed twice? Instead of keeping all the subexpressions around (a run-time cost), keep the AST of the expression itself (a compile-time cost). Then, when the exception is about to be printed to the console, re-evaluate it and do the display. ChrisA _______________________________________________ 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/IXPY4BRCZ3MPSSVBKWFYJGMR6ZHFGCJF/ Code of Conduct: http://python.org/psf/codeofconduct/
