=====================
 Development version
=====================

This document describes in-flight development work.

.. warning::

    Please do not edit this file by hand (doing so will likely cause merge
    conflicts for other Pull Requests). Instead, create a new file in the
    `docs/source/whatsnew/pr` folder


Released .... ...., 2017


Need to be updated:

.. toctree::
   :maxdepth: 2
   :glob:

   pr/*



Prompt Rendering Performance improvements
=========================================

Pull Request :ghpull:`11933` introduced an optimisation in the prompt rendering
logic that should decrease the resource usage of IPython when using the
_default_ configuration but could potentially introduce a regression of
functionalities if you are using a custom prompt.

We know assume if you haven't changed the default keybindings that the prompt
**will not change** during the duration of your input – which is for example
not true when using vi insert mode that switches between `[ins]` and `[nor]`
for the current mode.

If you are experiencing any issue let us know.

Code autoformatting
===================

The IPython terminal can now auto format your code just before entering a new
line or executing a command. To do so use the
``--TerminalInteractiveShell.autoformatter`` option and set it to ``'black'``;
if black is installed IPython will use black to format your code when possible.

IPython cannot always properly format your code; in particular it will
auto formatting with *black* will only work if:

   - Your code does not contains magics or special python syntax.

   - There is no code after your cursor.

The Black API is also still in motion; so this may not work with all versions of
black.

It should be possible to register custom reformatter, though the API is till in
flux.

Arbitrary Mimetypes Handing in Terminal
=======================================

When using IPython terminal it is now possible to register function to handle
arbitrary mimetypes. While rendering non-text based representation was possible in
many jupyter frontend; it was not possible in terminal IPython, as usually
terminal are limited to displaying text. As many terminal these days provide
escape sequences to display non-text; bringing this loved feature to IPython CLI
made a lot of sens. This functionality will not only allow inline images; but
allow opening of external program; for example ``mplayer`` to "display" sound
files.

So far only the hooks necessary for this are in place, but no default mime
renderers added; so inline images will only be available via extensions. We will
progressively enable these features by default in the next few releases, and
contribution is welcomed.

We welcome any feedback on the API. See :ref:`shell_mimerenderer` for more
informations.

This is originally based on work form in :ghpull:`10610` from stephanh42
started over two years ago, and still a lot need to be done.

.. DO NOT EDIT THIS LINE BEFORE RELEASE. FEATURE INSERTION POINT.


Backwards incompatible changes
------------------------------

.. DO NOT EDIT THIS LINE BEFORE RELEASE. INCOMPAT INSERTION POINT.