IPython 5.0 and key bindings in console

The new release of IPython does not depend any more on readline but uses the pure Python library prompt-toolkit, solving maintenance problems on Apple's and Windows' systems.

A new feature is the ability to edit a multi-line code block, using the cursor keys to move freely in the code block — with this power it comes, at least for me, a problem: because a ret inserts a new line in your code, to pass the whole block to the interpreter you have to use the shortcut alt+ret or possibly the less convenient key sequence esc followed by ret.

I say, this is a problem, because my terminal emulator of choice is the XTerm and, on many Linux distributions, the shortcut alt+ret is not passed to the application but it is directly used by the XTerm in which IPython is running, to toggle the screen-fullness of the said terminal (@ThomasDickey, xterm's mantainer and co-author pointed out that, by default, xterm doesn't care to send to the application the modifier bit on Enter even when one unbinds the Fullscreen action).

For this reason I'd like to modify at least this specific IPython key binding.

I've found instructions (sort of) for the previouos versions, the readline based ones, of IPython that do not apply to the new, 5.0 version.

What I would need are instructions that lead me to find, in IPython's user documentation, the names of the possible actions that I can bind, the names of the shortcuts to bind with the actions and the procedure to follow to configure a new key binding.

Failing to have this type of canonical answer, I may be happy with a recipe to accomplish this specific keybinding, with the condition that the recipe still works in IPython 6.0

Solution

You could change xterm's configuration.

xterm is configurable (and documented). In the xterm manual, the Default Key Bindings section shows the default binding for this key:

                        Alt <Key>Return:fullscreen() \n\

You can suppress that binding in more than one way:

using the omitTranslation resource to suppress the feature
setting the fullscreen resource to never

However, just suppressing it will not make it send something interesting (xterm ignores the modifier for Enter). Setting a translation resource works, e.g., in your $HOME/.Xdefaults file:

*VT100*translations:      #override \n\ 
     Alt <Key>Return: string("\033[27;3;13~")