PEP 701 – Syntactic formalization of f-strings

PEPs
68

Couldn’t resist…

def bart(foo):
    f"""{(

    foo := foo + 1,
    print('Finally, curly brackets in Python ;-)'),
    [
        print('Teacher: You should not use full Python in f-strings.')
        for i in range(foo)
    ],
    print(f'But you can... {foo}-)')

)}"""

bart(7)

…

Finally, curly brackets in Python ;-)
Teacher: You should not use full Python in f-strings.
Teacher: You should not use full Python in f-strings.
Teacher: You should not use full Python in f-strings.
Teacher: You should not use full Python in f-strings.
Teacher: You should not use full Python in f-strings.
Teacher: You should not use full Python in f-strings.
Teacher: You should not use full Python in f-strings.
Teacher: You should not use full Python in f-strings.
But you can... 8-)

This is already possible in 3.10, but I strongly doubt that it was ever intended. Should we really head on in the same direction even more ?

Just to be clear: I like the PEP and support it, since it simplifies the implementation and removes some annoying bits (e.g. the backslash limitation), but I don’t like the removal of the string literal quoting rules and support for arbitrary nesting of f-strings. By keeping the quote restriction, arbitrary nesting can be prevented.

8 Likes