[issue13214] Cmd: list available completions from the cmd.Cmd subclass and filter out EOF handler(s)

[Roundup Robot]

Change by Roundup Robot :


--
pull_requests: +16584
stage:  -> patch review
pull_request: https://github.com/python/cpython/pull/17074

___
Python tracker 

___
___
Python-bugs-list mailing list
Unsubscribe: 
https://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com

[issue13214] Cmd: list available completions from the cmd.Cmd subclass and filter out EOF handler(s)

[Kimball Leavitt]

Kimball Leavitt  added the comment:

I know that many people do something like:

def do_EOF(self, arg):
return True

to exit the program when you press Ctrl+d. Others might prefer something like 
ngie https://bugs.python.org/issue13214#msg145856:

def do_EOF(self, arg):
raise EOFError

The issue that I have is if the command you enter is 'EOF' (or 'EOF --some 
--arg'), you end up calling your do_EOF function. I think this unintended side 
effect could be avoided if the check for EOFError was removed and the exception 
was just raised. (see 
https://github.com/python/cpython/blob/master/Lib/cmd.py#L127).

--
nosy: +Kimball Leavitt

___
Python tracker 

___
___
Python-bugs-list mailing list
Unsubscribe: 
https://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com

[issue13214] Cmd: list available completions from the cmd.Cmd subclass and filter out EOF handler(s)

[Aldwin Pollefeyt]

Aldwin Pollefeyt  added the comment:

The EOF mentioned in msg309788 is the first reason why I searched in the 
library code for a solution. Then saw it as an opportunity to create hidden 
functions in the shell. So I created issue37030 [0] and PR13536 [1]. Later got 
notified about this thread.

[0] https://bugs.python.org/issue37030#msg343873
[1] https://github.com/python/cpython/pull/13536

--
nosy: +aldwinaldwin

___
Python tracker 

___
___
Python-bugs-list mailing list
Unsubscribe: 
https://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com

[issue13214] Cmd: list available completions from the cmd.Cmd subclass and filter out EOF handler(s)

[Raymond Hettinger]

Change by Raymond Hettinger :


--
assignee: rhettinger -> 

___
Python tracker 

___
___
Python-bugs-list mailing list
Unsubscribe: 
https://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com

[issue13214] Cmd: list available completions from the cmd.Cmd subclass and filter out EOF handler(s)

[Daniel]

Daniel  added the comment:

If you write a handler for EOF like so:

from cmd import Cmd

class FooShell(Cmd):
def do_EOF(self, args):
# exit on EOF
raise SystemExit()

shell = FooShell()
shell.cmdloop()

Then when running the shell, you can see "EOF" as an undocumented command in 
the help screen. You can see this when typing "?".

$ python fooshell.py
(Cmd) ?

Documented commands (type help ):

help

Undocumented commands:
==
EOF

I believe the correct behaviour should be (1) don't show it in the undocumented 
commands, since it's not really a command; and (2) maybe create a built-in 
command for this, since the literal string "EOF" is also caught by this handler.

--
nosy: +boompig
versions: +Python 3.6 -Python 3.3

___
Python tracker 

___
___
Python-bugs-list mailing list
Unsubscribe: 
https://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com

[issue13214] Cmd: list available completions from the cmd.Cmd subclass and filter out EOF handler(s)

[Catherine Devlin]

Catherine Devlin added the comment:

Needed to update the patch slightly for Python 3; now that filter() returns an 
iterator, ``do_help``'s call to 
names = self.get_names()
followed by
names.sort()
was throwing an error, so I changed get_names to return a list.

--
nosy: +Catherine.Devlin
Added file: 
http://bugs.python.org/file26593/python-cmd-better-filtering-py3.patch

___
Python tracker rep...@bugs.python.org
http://bugs.python.org/issue13214
___
___
Python-bugs-list mailing list
Unsubscribe: 
http://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com

[issue13214] Cmd: list available completions from the cmd.Cmd subclass and filter out EOF handler(s)

[Catherine Devlin]

Catherine Devlin added the comment:

Change to test_cmd.py to test for help displaying the name of the registered 
subcommand (as well as a simple test for the basic operation of the registered 
sub-CLI).

--
Added file: http://bugs.python.org/file26594/test_cmd.patch

___
Python tracker rep...@bugs.python.org
http://bugs.python.org/issue13214
___
___
Python-bugs-list mailing list
Unsubscribe: 
http://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com

[issue13214] Cmd: list available completions from the cmd.Cmd subclass and filter out EOF handler(s)

[Garrett Cooper]

Garrett Cooper yaneg...@gmail.com added the comment:

Here's a version incorporating your suggestion and better documenting the 
choices and the method for overriding purposes. I have a few reservations with 
the current implementation:

1. As noted, the information for the class really could be and should be cached 
as the attributes of a given cmd.Cmd derived class don't change all that 
frequently.
2. One has to override the entire function in order to get what I consider 
standard functionality (filtering).. so I don't know if that's a good idea.
3. I've thought about the do_EOF handler stuff, and it would be nice if that 
was shoved into the completer method(s) as a keyword argument, defaulting to 
False -- that way one could avoid having to explicitly install an EOF handler 
when dealing with ^D, etc, but this can be hashed out better in a different 
issue, over IRC, email, etc.

This module could be better cleaned up (isn't PEP8 compliant, overrides 
built-ins, is pythonic but not super pythonic, etc), but I'll see what other 
modules exist out there that could be used in its place, because they could 
have resolved some of these issues. There is some value that can be obtained 
from pexpect, some of the other cmd module variants, etc .. I just like this 
module because it's nice, simple, and standard -- it just needs a little love 
and it will be awesome.

Anyhow -- thanks again for the work :).

--
Added file: http://bugs.python.org/file23485/python-cmd-better-filtering.patch

___
Python tracker rep...@bugs.python.org
http://bugs.python.org/issue13214
___
___
Python-bugs-list mailing list
Unsubscribe: 
http://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com

[issue13214] Cmd: list available completions from the cmd.Cmd subclass and filter out EOF handler(s)

[Garrett Cooper]

New submission from Garrett Cooper yaneg...@gmail.com:

1. The current code in cmd.get_names does a dir on the derived class for
   cmd.Cmd object instead, which means that if I do something similar to
   the following:

class CLI(cmd.Cmd):
   def register_subcommand(self, cmd, cli_class):
   def call_cli(self):
   cli = cli_class()
   cli.cmdloop()
   setattr(self, 'do_%s' % (cmd, ), call_cli)

   it won't register the command in the completion list or help list.

2. Registering a do_EOF handler is a bit of a hack to work around
   the fact that entering in ^D on the command line prints out:

   (Cmd) *** Unknown syntax: EOF

   I can't speak to the fact that my desired behavior should be 
   enforced (basically trickle up the EOFError like so):

   def do_EOF(self, arg):
   raise EOFError

   so what I'm proposing instead is that it be filtered out by default.

Given that there's some value in allowing developers to build custom filter 
rules for the completions (example: certain commands can be undocumented, 
hidden to lower privilege users, etc), I figured it would be wise to create a 
custom mechanism for filtering out commands.

This could be cleaned up to use better python idioms like a generator, cache 
the data and have a refresh method, etc, but this is a good first start.

--
components: Library (Lib)
files: python-cmd-better-filtering.patch
keywords: patch
messages: 145856
nosy: yaneurabeya
priority: normal
severity: normal
status: open
title: Cmd: list available completions from the cmd.Cmd subclass and filter out 
EOF handler(s)
type: feature request
versions: Python 2.7, Python 3.4
Added file: http://bugs.python.org/file23449/python-cmd-better-filtering.patch

___
Python tracker rep...@bugs.python.org
http://bugs.python.org/issue13214
___
___
Python-bugs-list mailing list
Unsubscribe: 
http://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com

[issue13214] Cmd: list available completions from the cmd.Cmd subclass and filter out EOF handler(s)

[Raymond Hettinger]

Raymond Hettinger raymond.hettin...@gmail.com added the comment:

This looks to be a reasonable request.

I think the patch would be better if the filtering were done directly in 
get_names().  A subclass can override or extend that method if it wants to 
customize the filter.

--
assignee:  - rhettinger
nosy: +rhettinger
versions: +Python 3.3 -Python 2.7, Python 3.4

___
Python tracker rep...@bugs.python.org
http://bugs.python.org/issue13214
___
___
Python-bugs-list mailing list
Unsubscribe: 
http://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com