[IPython-dev] Request: IPython.ext namespace

Takafumi Arakaki aka.tkf@gmail....
Thu Oct 25 16:04:28 CDT 2012

On Thu, Oct 25, 2012 at 9:41 PM, Jake Vanderplas
<vanderplas@astro.washington.edu> wrote:
> Hi,
> There's one particularly difficult issue with disparate packages sharing
> a namespace: multiple install paths cause problems.  For example, if you
> have a system-wide ipython installation and then install a new extension
> in a local folder, you can get an import error because the extension
> does not exist in the first version of the namespace found by python.
> This was one of the main problems that led to deprecation of the scikits
> namespace.
>     Jake

I see.  That's the fundamental problem.  Shared namespace definitely
not good idea then!

I'd like to have some rule such as ipyext_ prefix though.  But as
packages may have IPython extension as submodule like sympy does it
won't be constant anyway.

> On 10/25/2012 12:28 PM, Takafumi Arakaki wrote:
>> Hi,
>> I think IPython should provide namespace for IPython extensions, so
>> that extension authors can upload their extensions to PyPI.  I don't
>> care about what the actual name is (probably it can be ipythonext,
>> IPythonContrib, IPython.extensions, or what ever).  It is something
>> what Sphinx does for "sphinxcontrib.*" namespace.  I can think of many
>> reasons why it is better for IPython extension users and authors:
>> 1. When you want to use external Python module in your extension,
>>     currently there is no easy way to install it.  If you can upload
>>     your extension as `IPython.ext.YOUREXT`, it can be easily solved.
>> 2. Similarity, you can depends on other IPython extensions.  Currently
>>     there is no easy way to import other IPython extensions.
>> 3. It does not stop people using `%install_ext`.  If your extension is
>>     just one file, you can just do::
>>       %install_ext
>> https://raw.github.com/YOU/ipython-ext-YOUREXT/master/IPython/ext/YOUREXT.py
>> 4. You get IPython extension search engine for free.  People can just do::
>>       pip search IPython.ext
>>     Try ``pip search sphinxcontrib``, for example.
>> 5. It helps people avoiding namespace collision.  Currently there is
>>     no easy way to make sure if other people not using some name.
>>     Sure, you can google it, but you can't be 100% sure.
>> 6. IPython don't need to create any machinery for this.  All you need
>>     to do is to put some notice in the documentation for extension
>>     author.
>> To be fair, I will try to think the reasons why you should not do this:
>> 1. It may drive lazy people away from writing it.  "Oh, I need setup.py
>>     for IPython extension?  No... I won't upload it hen."
>>     (But you don't need to upload your extension to pypi, if your
>>     extension is just one file.)
>> 2. It increases the amount and complexity of documentation you need to
>>     maintain.  You need to explain:  "You can install extensions using
>>     `pip` (or `easy_install`, if you want).  Oh, you can use
>>     `%install_ext` magic by the way.  But it cannot be used for some
>>     packages blah blah blah...".
>> BTW, should I post something like this in ML or github issue?  As
>> there was old discussion in this ML [1]_, I am posting it here.
>> .. [1] http://mail.scipy.org/pipermail/ipython-dev/2012-June/thread.html#9427
>> --
>> Takafumi Arakaki
>> https://github.com/tkf
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