[IPython-dev] Extensible pretty-printing

Robert Kern robert.kern at gmail.com
Thu Oct 28 11:07:17 EDT 2010

On 10/27/10 9:52 PM, Fernando Perez wrote:
> Howdy,
> On Wed, Oct 27, 2010 at 8:37 AM, Robert Kern<robert.kern at gmail.com>  wrote:
>> In the ticket discussion around my patch to restore the result_display hook,
>> Brian suggested that the real issue is what the extensibility API for this
>> functionality should be. I would like to propose the pretty extension as that
>> API. I propose that it should be integrated into the core of IPython as the
>> pretty-printer instead of pprint. pretty allows one to specify pretty-print
>> functions for individual types and have them used in nested contexts.
> I've been looking carefully at the CommandChainDispatcher code, since
> you raised the design points about it in the discussion on github.  I
> agree that it's a very reasonable design pattern and we're likely to
> end up re-implementing something quite similar to it if we discard it,
> so there's no need to.  It just needs a few tests to pin down the
> expected functionality for the long run, and I'd like to change the
> notion that undispatched functions in the chain can modify the
> arguments along the way.  That just seems to me like a source of
> hard-to-find bugs and I fail to see the need for it.  But otherwise I
> have no problems with it.

Well, although I said that before, I do think that pretty's API makes 
CommandChainDispatcher irrelevant for this use case, and I think we should just 
use it directly here.

Robert Kern

"I have come to believe that the whole world is an enigma, a harmless enigma
  that is made terrible by our own mad attempt to interpret it as though it had
  an underlying truth."
   -- Umberto Eco

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