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.
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