Absolute seeking on a StringIO treats the offset as a character count regardless of the contents, so given that there is no "pretend it's UTF-8 and advance a given number of 'bytes'" machinery anyway, there's no reason not to allow seeking relative to the current location or the end of the 'file'. The error message is also misleading: "Can't do nonzero cur-relative seeks" even when the seek is relative to the end.
Sounds like you should just submit a bug report (and a PR with a fix if you feel up to it). Since a relative seek to position p is typically just implemented as an absolute seek to position f.tell()+p, this looks like an odd omission, and I can't remember a reason for it. Looking at the code, the fix looks pretty easy -- update _io_StringIO_seek_impl() in Modules/_io/stringio.c. On Thu, Jan 16, 2020 at 7:19 PM Random832 <random832@fastmail.com> wrote:
-- --Guido van Rossum (python.org/~guido) *Pronouns: he/him **(why is my pronoun here?)* <http://feministing.com/2015/02/03/how-using-they-as-a-singular-pronoun-can-c...>
On Thu, Jan 16, 2020, at 23:07, Guido van Rossum wrote:
I guess my instinct was to post here first in case there was (or in case someone thought there was) a reason, since it's certainly something that's being specifically disallowed in the code rather than a consequence of something that's not checked properly. Submitted as issue 39365.
Sounds like you should just submit a bug report (and a PR with a fix if you feel up to it). Since a relative seek to position p is typically just implemented as an absolute seek to position f.tell()+p, this looks like an odd omission, and I can't remember a reason for it. Looking at the code, the fix looks pretty easy -- update _io_StringIO_seek_impl() in Modules/_io/stringio.c. On Thu, Jan 16, 2020 at 7:19 PM Random832 <random832@fastmail.com> wrote:
-- --Guido van Rossum (python.org/~guido) *Pronouns: he/him **(why is my pronoun here?)* <http://feministing.com/2015/02/03/how-using-they-as-a-singular-pronoun-can-c...>
On Thu, Jan 16, 2020, at 23:07, Guido van Rossum wrote:
I guess my instinct was to post here first in case there was (or in case someone thought there was) a reason, since it's certainly something that's being specifically disallowed in the code rather than a consequence of something that's not checked properly. Submitted as issue 39365.
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