[IPython-dev] IPython pyreadline improvement of IPython

Fernando Perez Fernando.Perez at colorado.edu
Sun Jan 29 16:42:52 EST 2006

Vivian De Smedt wrote:

> I know that Fernando is on something big that will make all that 
> pathetic

Not at all: what I'm working on is long-term, and will take a while to bear 
fruit in a way that directly benefits today's ipython users.  It's important 
to understand that much of what is happening in the chainsaw effort is geared 
towards other goals, mostly ones of direct relevance to scientific computing 
(high-level access to parallel computing resources, GUIs which integrate with 
Latex and matplotlib to produce scientific documents, etc.).

This same architecture will allow, at the end, a new ipython to be built with
similar features to today's, and on top of a cleaner set of internals, but it 
won't necessarily provide many new features for plain-terminal usage.

For these reasons, the current cleanup and improvements Ville and others like 
yourself are working on are very important, and I expect the stable branch to 
remain the tool of choice for interactive work for quite a while.  I simply 
needed to move my energy into something more in line with my 'regular' 
professional activities (applied mathematics and scientific computing).

So by all means continue the work on trunk/: it's where the payoff is today, 
and we will all benefit from it.  I will also contribute there when I can, but 
I'm glad that Ville and others with more time than myself to work here are 
leading the charge.

Finally, it's important to note that there are rumblings in python-dev about 
perhaps dropping readline support from Python in the future.  The problem is 
that readline is GPL, and it's not 100% clear whether Python may be violating 
the GPL by linking to it as it does today.  This is all the more reason to 
push for the development of our own readline, as it might even solve a problem 
for the Python core in the future.  Note that python-dev has NOT decided to 
drop readline, they've just been going back and forth about the problem. 
Google for the info if you are curious (it's scattered on various threads).

> For Multi-line statement my idea is.
>     History is only made of one line statement and the first line of the
>     multi-line statement.
>     When we start editing a multi-line statement the down arrows let us
>     add the lines of the multi-line statement.
>     Suppose you made a mistake in the third line of a three lines
>     statement. Now you have to type.
>     up-up-up-return up-up-return up-up-[correction]-return
>     And with my proposition you will have to type
>     up-return down-return down-[correction]-return

This has actually been requested for ipython by SAGE, but we can't offer it 
today (given readline's limitations).  Having our own readline where this 
could be done would be great.



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