Append space after completed keywords

[serhiy-storchaka]

BPO	25209
Nosy	@Yhg1s, @pitrou, @vstinner, @bitdancer, @vadmium, @serhiy-storchaka
Files	rlcompleter_keyword_space.patch rlcompleter_keyword_space_2.patch rlcompleter_keyword_space_3.patch

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

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GitHub fields:

assignee = 'https://github.com/serhiy-storchaka'
closed_at = <Date 2015-09-27.10:47:57.388>
created_at = <Date 2015-09-21.21:25:13.997>
labels = ['extension-modules', 'type-feature']
title = 'Append space after completed keywords'
updated_at = <Date 2015-09-27.10:47:57.386>
user = 'https://github.com/serhiy-storchaka'

bugs.python.org fields:

activity = <Date 2015-09-27.10:47:57.386>
actor = 'serhiy.storchaka'
assignee = 'serhiy.storchaka'
closed = True
closed_date = <Date 2015-09-27.10:47:57.388>
closer = 'serhiy.storchaka'
components = ['Extension Modules']
creation = <Date 2015-09-21.21:25:13.997>
creator = 'serhiy.storchaka'
dependencies = []
files = ['40538', '40549', '40561']
hgrepos = []
issue_num = 25209
keywords = ['patch']
message_count = 11.0
messages = ['251262', '251282', '251332', '251347', '251511', '251513', '251514', '251515', '251628', '251698', '251700']
nosy_count = 7.0
nosy_names = ['twouters', 'pitrou', 'vstinner', 'r.david.murray', 'python-dev', 'martin.panter', 'serhiy.storchaka']
pr_nums = []
priority = 'normal'
resolution = 'fixed'
stage = 'resolved'
status = 'closed'
superseder = None
type = 'enhancement'
url = 'https://bugs.python.org/issue25209'
versions = ['Python 3.6']

[serhiy-storchaka]

Open parenthesis ('(') is appended after completed callable globals and attributes. I propose to add a space after completed keyword. In most cases a space is either required after the keyword, or recommended by PEP-8. Attached patch implements this.

[vadmium]

I agree with adding a space in some cases, but not others. E.g. "pass" would only need a space if you wanted to add a comment, "return" often takes no argument, "lambda" may need an immediate colon (lambda: x). See <https://github.com/vadmium/etc/blob/0f8d459/python/pythonstartup.py#L210\> for a whitelist of keywords that I thought should always have spaces, but beware this list may not be up to date (no “await” nor “async” for instance).

BTW I don’t agree with the default of forcing an open bracket “(” for callables; consider decorators, subclassing, deferred function calls, etc, where that bracket may not be wanted.

[serhiy-storchaka]

Good catch Martin. Indeed, "pass", "break" and "continue" don't need a space, and "True", "False" and "None" need a space only in rare cases like "None in collection". Some keywords ("else", "finally", "try") need a colon. But while "return" and "lambda" not always need a space, I think that needing a space is more common case, and in any case the redundant space doesn't make a harm.

Here is revised patch that doesn't add a space in some cases and instead adds a colon in some cases.

[vadmium]

“Else” doesn’t always use a colon. Consider “1 if x else 2”. Again, if Python started adding unwanted spaces and colons I imagine users could be annoyed and think Python is being too smart and complicated for its own good. But maybe see what others say.

[vstinner]

I tested the patch. "wi<tab>" displays "with " (space)., but "fo<tab>" displays "for" (no space). I don't understand why. Well, it's not a big issue, anyway the patch looks good to me. IMHO you should apply it to Python 3.4-3.6 (not only 3.6).

[vadmium]

Victor, maybe because “for” also stands for “format”?

[serhiy-storchaka]

“Else” doesn’t always use a colon. Consider “1 if x else 2”.

Good catch Martin. Unfortunately the completer doesn't take context into account. "else" with a colon is a common case, but unwanted colon could be annoyed. I agree that it would be safe to not append a colon after "else". At least unless we make the completer context aware. However I don't think that unwanted space would be so annoyed. Here is updated patch.

I see that your code does an autocompletion for module names in "import", Martin. This was my next idea. Do you want to provide a patch for including this in CPython?

I tested the patch. "wi<tab>" displays "with " (space)., but "fo<tab>" displays "for" (no space). I don't understand why.

Because there is "format(".

IMHO you should apply it to Python 3.4-3.6 (not only 3.6).

This is definitely a new feature. And there is a risk to break something (if standard completer is used programmatic).

[vstinner]

This is definitely a new feature. And there is a risk to break something (if standard completer is used programmatic).

Ok, it's up to you.

[vadmium]

Yes I am interesting in making a patch for auto-completing module names. I’ll leave it on my to-do list, but don’t expect it overnight. :) My code does some rough parsing of Python syntax, but maybe that is not needed for “import x”, though it might be needed to support module attributes for “from x import y”.

[python-dev]

New changeset f64ec4aac935 by Serhiy Storchaka in branch 'default':
Issue bpo-25209: rlcomplete now can add a space or a colon after completed keyword.
https://hg.python.org/cpython/rev/f64ec4aac935

[serhiy-storchaka]

Thank you for your review Martin. Hope to see your patch for completing import statement.