I don't think that would be a good idea since we already have .format() which covers that use case and is more flexible than f-strings (it supports positional arguments, as well as *args and **kwargs).
I think keeping f-strings simple is a better idea. Best, Luciano On Thu, Jun 24, 2021 at 1:30 PM Eric Nieuwland <eric.nieuwl...@gmail.com> wrote: > > In a recent discussion with a colleague we wondered if it would be possible > to postpone the evaluation of an f-string so we could use it like a regular > string and .format() or ‘%’. > > I found > https://stackoverflow.com/questions/42497625/how-to-postpone-defer-the-evaluation-of-f-strings > and tweaked it a bit to: > > import inspect > > class DelayedFString(str): > def __str__(self): > vars = inspect.currentframe().f_back.f_globals.copy() > vars.update(inspect.currentframe().f_back.f_locals) > return self.format(**vars) > > delayed_fstring = DelayedFString("The current name is {name}") > > # use it inside a function to demonstrate it gets the scoping right > def new_scope(): > names = ["foo", "bar"] > for name in names: > print(delayed_fstring) > > new_scope() > > > While this does what it should it is very slow. > So I wondered whether it would be an idea to introduce d-strings (delayed > f-strings) and make f-strings syntactic sugar for > > f"The current name is {name}" = str(d"The current name is {name}") > > > And perhaps access to the variables and conversions specified in the d-string. > > _______________________________________________ > 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/GT5DNA7RKRLFWE3V42OTWB7X5ER7KNSL/ > Code of Conduct: http://python.org/psf/codeofconduct/ -- Luciano Ramalho | Author of Fluent Python (O'Reilly, 2015) | http://shop.oreilly.com/product/0636920032519.do | Technical Principal at ThoughtWorks | Twitter: @ramalhoorg _______________________________________________ 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/LVPDNGURA677ODMLBVUURPXKYGBKJ6A4/ Code of Conduct: http://python.org/psf/codeofconduct/
