[IPython-dev] Function specific hooks into the ipython tab completion system

[Robert McGibbon]

Hi,

Good spot, Matthias. I didn't see that method was already exposed -- I was just looking at IPCompleter.matchers, which what that method inserts into.

Annotations are cool, but they're not obviously composable. I worry that if I use them for this and then fix one syntax of how the annotation is parsed, and somebody else
is using annotations in their lib for something else, the two schemes won't be able to interoperate. Also they're py3k only.

My preferred syntax would be

from tablib import tabcompletion, filename,

@tabcompletion(fname=filename, mode=['r', 'w'])
def load(fname, mode, other_argument):
    pass

or maybe with a parameterized filename to get specific extensions

@tabcompletion(fname=filename('.txt'))
def f(fname, other_argument):
    pass

Is this something that other people would be interested in?

-Robert

On Nov 29, 2012, at 2:02 AM, Matthias BUSSONNIER wrote:

> Hi, 
> 
> I may be wrong, but IIRC you can insert your own completer in the IPython  completer chain and decide to filter the previous completion.
> 
> You should be able to have a custom completer that just forward the previous completion in most cases, 
> And just do a dir completion if the object is np.loadtxt in your case (or look at __annotations__ if you wish).
> 
> I've found one reference to inserting custom completer here
> http://ipython.org/ipython-doc/dev/api/generated/IPython.core.interactiveshell.html?highlight=interactiveshell#IPython.core.interactiveshell.InteractiveShell.set_custom_completer
> 
> 
> -- 
> Matthias
> 
> Le 29 nov. 2012 à 10:27, Aaron Meurer a écrit :
> 
>> I've often thought this as well.  Probably a full-blown IPEP is in
>> order here.  Perhaps __annotations__ would be the correct way to go
>> here.
>> 
>> Aaron Meurer
>> 
>> On Thu, Nov 29, 2012 at 12:58 AM, Robert McGibbon <rmcgibbo at gmail.com> wrote:
>>> Hey,
>>> 
>>> Tab completion in IPython is one of the things that makes it so useful,
>>> especially the context specific tab completion for things like "from ..."
>>> where only packages, or obviously the special completion for attributes when
>>> the line contains a dot.
>>> 
>>> I use IPython for interactive data analysis a lot, and one of the most
>>> frequent operations is loading up data with something like numpy.loadtxt()
>>> or various related functions.
>>> 
>>> It would be really awesome if we could annotate functions to interact with
>>> the tab completion system, perhaps for instance saying that argument 0 to
>>> numpy.loadtxt() is supposed to be a filename, so let's give tab-complete
>>> suggestions that try to look for directories/files. Some functions only
>>> files with specific extensions, so you could filter based on that or
>>> whatever.
>>> 
>>> By hacking on the code for completerlib.py:cd_completer, I sketched out a
>>> little demo of what you could do with this: https://gist.github.com/4167151.
>>> The architecture is totally wrong, but it lets you get behavior like:
>>> 
>>> ```
>>> In [1]: ls
>>> datfile.dat  dir1/        dir2/        file.gz      random_junk  test.py
>>> 
>>> In [2]: directory_as_a_variable = 'sdfsfsd'
>>> 
>>> In [3]: f = np.loadtxt(<TAB>
>>> datfile.dat  dir1/        dir2/        file.gz
>>> 
>>> In [4]: normal_function(<TAB>
>>> Display all 330 possibilities? (y or n)
>>> 
>>> In [5]: g = np.loadtxt(di<TAB>
>>> dict                      dir1/                     directory_as_a_variable
>>> divmod
>>> dir                       dir2/                     directory_of_my_choosing
>>> ```
>>> 
>>> Basically hitting the tab completion, when np.loadtxt is on the input line,
>>> only shows directories and files that end with a certain extension. If you
>>> start to type in the name of an object in your namespace, it'll show up too,
>>> but only once you've typed in more than 1 matching character.
>>> 
>>> The implementation in my gist is pretty lame. The way I've coded it up, the
>>> special behavior is based on simply finding the string "np.loadtxt" on the
>>> input line, not on the actual function. This means you can't really make the
>>> behavior specific to your position in the argument list (i.e. I know that
>>> the first arg is a filename, and so should be tab completed like this, but
>>> the other ones are not). I suspect the right way to do the implementation is
>>> via function decorators to specify the behavior and then adding to
>>> IPCompleter instead.
>>> 
>>> I think I'm up for giving this a shot.
>>> 
>>> Thoughts? Is this a feature anyone else would find interesting?
>>> 
>>> -Robert
>>> 
>>> 
>>> 
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