Currently format strings (and f-string expressions) support three conversions: !s -- str, !r -- repr and !a for ascii. I propose to add support of additional conversions: for int, float and operator.index. It will help to convert automatically printf-like format strings to f-string expressions: %d, %i, %u -- use int, %f -- use float, %o, %x -- use operator.index. For float the conversion letter is obvious -- !f. But I am not sure for what !i should be used, for int or operator.index. If make it operator.index, then !d perhaps should be used for int. If make it int, then !I perhaps should be used for operator.index. Or vice verse? Also I propose to support applying multiple conversions for the same item. It is common when you output a path or URL object as quoted string with all escaping, because in general it can contain special or non-printable characters. Currently I write f"path = {repr(str(path))}" or f"path = {str(path)!r}", but want to write f"path = {path!s!r}". Do we need support of more standard conversions? Do we want to support custom conversions (registered globally as encodings and error handlers). re.escape, html.escape and shlex.quote could be very useful in some applications.