PEP 701 – Syntactic formalization of f-strings

[guido (Guido van Rossum)]

@pablogsal

In general, we found that just modifying the tokenizer to know when to switch is not only much easier, but also much cleaner and debuggable, and requires many many fewer changes. At the end of the day, one of our cornerstones is making this part of CPython more maintainable so our implementation went this route.

Thanks, this actually makes sense.

Trying to get the discussion back on track (away from .join()) a bit, have you thought about my parenthetical remark about using \{ and \} to escape curlies instead of, or in addition to, {{ and }}? I believe that when PEP 498 was discussed, there was a good reason to use the latter, but somehow I can’t find that reason in the PEP, and I can’t recall what it was. Maybe it was for compatibility with str.format()? The doubling has always irked me, and I think I’ve forgotten that it existed several times over the years (because I so rarely have a real need to put a curly brace in an f-string).