Remove <> operator from Grammar/Grammar

[elibendersky]

BPO	13239
Nosy	@freddrake, @warsaw, @brettcannon, @ncoghlan, @pitrou, @benjaminp, @merwok, @florentx
Files	issue13239.patch

^{Note: these values reflect the state of the issue at the time it was migrated and might not reflect the current state.}

Show more details

GitHub fields:

assignee = None
closed_at = <Date 2011-11-13.23:08:23.967>
created_at = <Date 2011-10-21.09:11:20.365>
labels = ['interpreter-core', 'type-bug', 'docs']
title = 'Remove <> operator from Grammar/Grammar'
updated_at = <Date 2011-11-14.13:23:41.384>
user = 'https://bugs.python.org/elibendersky'

bugs.python.org fields:

activity = <Date 2011-11-14.13:23:41.384>
actor = 'eric.araujo'
assignee = 'docs@python'
closed = True
closed_date = <Date 2011-11-13.23:08:23.967>
closer = 'python-dev'
components = ['Documentation', 'Interpreter Core']
creation = <Date 2011-10-21.09:11:20.365>
creator = 'eli.bendersky'
dependencies = []
files = ['23656']
hgrepos = []
issue_num = 13239
keywords = ['patch']
message_count = 15.0
messages = ['146070', '146071', '146072', '146110', '146111', '146113', '146116', '146117', '146118', '147424', '147447', '147509', '147519', '147576', '147592']
nosy_count = 11.0
nosy_names = ['fdrake', 'barry', 'brett.cannon', 'ncoghlan', 'pitrou', 'benjamin.peterson', 'eric.araujo', 'eli.bendersky', 'flox', 'docs@python', 'python-dev']
pr_nums = []
priority = 'normal'
resolution = 'fixed'
stage = 'resolved'
status = 'closed'
superseder = None
type = 'behavior'
url = 'https://bugs.python.org/issue13239'
versions = ['Python 3.2', 'Python 3.3']

[elibendersky]

Operator <> was removed in Python 3, but still appears in Grammar/Grammar (and hence in Doc/reference/grammar.rst)

Reported by Alexander Ivanyuta on the docs mailing list

[elibendersky]

The relevant code in Parser/parsetok.c is:

#ifdef PY_PARSER_REQUIRES_FUTURE_KEYWORD
        if (type == NOTEQUAL) {
            if (!(ps->p_flags & CO_FUTURE_BARRY_AS_BDFL) &&
                            strcmp(str, "!=")) {
                err_ret->error = E_SYNTAX;
                break;
            }
            else if ((ps->p_flags & CO_FUTURE_BARRY_AS_BDFL) &&
                            strcmp(str, "<>")) {
                err_ret->text = "with Barry as BDFL, use '<>' "
                                "instead of '!='";
                err_ret->error = E_SYNTAX;
                break;
            }
        }
#endif

Hmm... I'm too new to remember this joke, but here it presents a practical problem - since Grammar/Grammar is being directly reflected into the documentation (.. literalinclude:: ../../Grammar/Grammar) and thus can confuse.

Is it safe to just remove the whole thing from Grammar/Grammar and correspondingly Parser/parsetok.c ?

[florentx]

This is PEP-401.

"[Because] the != inequality operator ... was a horrible, finger pain inducing mistake, the FLUFL reinstates the <> diamond operator as the sole spelling. This change is important enough to be implemented for, and released in Python 3.1. To help transition to this feature, a new future statement, from __future__ import barry_as_FLUFL has been added."

[brettcannon]

Probably need a comment in the Grammar file so people know why an
unused operator is in there.

[benjaminp]

Or perhaps we don't need joke backward compatibility? (That's nearly 3 years old.)

[brettcannon]

On Fri, Oct 21, 2011 at 11:35, Benjamin Peterson <report@bugs.python.org> wrote:

Benjamin Peterson <benjamin@python.org> added the comment:

Or perhaps we don't need joke backward compatibility? (That's nearly 3 years old.)

Then you tell the FLUFL that you want to take his precious operator away. =)

[warsaw]

On Oct 21, 2011, at 06:35 PM, Benjamin Peterson wrote:

Benjamin Peterson <benjamin@python.org> added the comment:

Or perhaps we don't need joke backward compatibility? (That's nearly 3 years
old.)

OTOH, __future__ imports (even jokes) should never be removed.

[pitrou]

OTOH, __future__ imports (even jokes) should never be removed.

But their meaning can be altered?
(as part of another joke if you want :)

[warsaw]

On Oct 21, 2011, at 07:33 PM, Antoine Pitrou wrote:

Antoine Pitrou <pitrou@free.fr> added the comment:

> OTOH, __future__ imports (even jokes) should never be removed.

But their meaning can be altered?
(as part of another joke if you want :)

Well, you have 6 months to work that out then. :)

[elibendersky]

Attaching a patch with a clarifying comment in Grammar/Grammar. Should be enough for now?

[brettcannon]

I think the clarification should be enough.

[merwok]

+1 for a comment too. I’d even make it shorter:

# don't look at <>, it's not a real operator (see PEP-401)

[elibendersky]

Éric, do you feel strongly about the wording, or can I just go ahead and commit my version if I like it more :) ?

[python-dev]

New changeset a259511351d9 by Eli Bendersky in branch '3.2':
Clarify the existence of the <> operator in Grammar/Grammar with a comment, for bpo-13239
http://hg.python.org/cpython/rev/a259511351d9

New changeset 410115400838 by Eli Bendersky in branch 'default':
Clarify the existence of the <> operator in Grammar/Grammar with a comment. Closes bpo-13239
http://hg.python.org/cpython/rev/410115400838

[merwok]

+# <> isn't actually a valid comparison operator in Python. It's here for the
+# sake of a __future__ import described in PEP-401

If we wanted to be exact, the operator isn’t here for a __future__ import but for a feature enabled by a __future__ import. But I don’t feel strongly about this at all :)