Serhiy Storchaka <storchaka+cpyt...@gmail.com> added the comment:
I only seen this idiom in the code of Argument Clinic (written by Larry). I am sure that it is used in third-party code, but I do not know how common is it. As for the proposed code, checking that the value is a string is not enough. 1. It can be a str subclass with an overridden __format__. In this case the result will be different. 2. If it is a str subclass without an overridden __format__, the optimization adds an overhead for looking up and calling the __format__ method. It can reverse the benefit in this case. To fix this you can skip formatting for this "converter". But there is a corner case for ''.join([value]). The result should always be a str. It may be complicated. You may need two new converter codes. 3. It is worth to merge consequent string constants and skip empty string constants. '/'.join([base, 'data', user_arg]) should produce [base, '/data/', user_arg] instead of [base, '/', 'data', '/', user_arg], and ''.join([base, 'data', user_arg]) should produce [base, 'data', user_arg] instead of [base, '', 'data', '', user_arg]. ---------- _______________________________________ Python tracker <rep...@bugs.python.org> <https://bugs.python.org/issue44194> _______________________________________ _______________________________________________ Python-bugs-list mailing list Unsubscribe: https://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
