[IPython-dev] Highlight lines of code in code cells?

[Mark Voorhies]

On 12/02/2013 03:19 PM, Greg Wilson wrote:
> On 2013-12-02 5:03 PM, Mark Voorhies wrote:
>> On 12/02/2013 09:26 AM, Eric Matthes wrote:
>>> I am not very familiar with the codebase yet, and I have few "good long
>>> afternoons" at this time of the year. I don't want to clutter my notebooks
>>> in a way that will be laborious to clean, so I think will use the
>>> commenting approach I described above, but also write a quick script that
>>> strips the notebooks of these formatting comments. This way anyone who is
>>> using the raw notebooks for their own purposes can choose to use my hack,
>>> or have a set of clean, unhighlighted notebooks to work with.
>>>
>>> I like the efficiency of your approach, though, so when I do get a nice
>>> afternoon to hack I will play with that approach. If anyone else has a good
>>> suggestion, I'd love to hear it as well.
>>>
>>> Thanks.
>>>
>>> Eric
>>>
>>>
>>> On Mon, Dec 2, 2013 at 8:01 AM, Matthias BUSSONNIER <
>>> bussonniermatthias at gmail.com> wrote:
>>>
>>>> Le 2 déc. 2013 à 17:37, Eric Matthes a écrit :
>>>>
>>>>> Hello,
>>>>>
>>>>> I often use IPython Notebook to write tutorials. In tutorials, I find it
>>>> helpful to highlight the lines of code that are being changed in each
>>>> iteration of a project. Is there a straightforward way to highlight
>>>> individual lines of code within a code cell?
>>>>> I came up with one approach, but it feels like an ugly hack. I write a
>>>> comment before the line[s] I want to highlight, and a comment after. Then
>>>> when converting to html I convert these comment lines to <b> and </b>. This
>>>> works, but it clutters the raw notebook file with formatting comments.
>>>>> ##bold
>>>>> print("I'd like to highlight this line.")
>>>>> ##/bold
>>>>>
>>>>> becomes:
>>>>>
>>>>> <b>print("I'd like to highlight this line.")</b>
>>>>>
>>>>> Is there a better way?
>>>> One could bind code mirror gutter event (click on line number) to store
>>>> metadata into the cells,
>>>> and write a custom highlighter for the templates in nbconvert.
>>>> This is more or less the only thing I  see. I would say that it's a good
>>>> long afternoon hack if you
>>>> are familiar with the codebase/codemirror and Pygment.
>>>>
>>>> It would have the advantage that you can easily toggle this highlight on
>>>> and of with a flag.
>>>>
>>>> --
>>>> Matthias
>> It would be very nice to have this as a cell magic that would highlight lines not in a reference
>> cell (or render as a diff relative to the reference cell).
>>
>> E.g.,
>>
>> [23] def Hello():
>>           print "Hello, World"
>>
>> [24] %%diff 23
>>         def Hello(s)
>>           print "Hello, %s" % s
>>
>> No idea how to do this, though =)
>>
>> --Mark
>>
> Software Carpentry would really like this feature as well, but I'd
> prefer not to tie it to cell numbers, since they change as the notebook
> is re-executed.  Instead, could we use cell tagging to give cells names,
> then display the diff against a named cell?
> Thanks,
> Greg

Just started fiddling with this, using rmagic.py and cythonmagic.py as references.

Can anyone point me at documentation for getting at retrieving cell content by
number and/or tag via the IPython shell instance?

Thanks,

Mark