[IPython-dev] messaging protocol

Jason Grout jason-sage at creativetrax.com
Sat Apr 9 11:47:45 EDT 2011

On 4/9/11 7:21 AM, Thomas Kluyver wrote:
> On 9 April 2011 07:30, Jason Grout <jason-sage at creativetrax.com
> <mailto:jason-sage at creativetrax.com>> wrote:
>     Interesting.  So execution count really is just a counter on
>     executions where the namespace is preserved.  What do you mean by
>     "namespace is preserved"?  How do you test for it?
> Well, if I do "a=12" <compute>, "a" <compute>, I will get 12 back if the
> namespace is preserved, but get a NameError if not. A quick test with
> aleph suggests that it's not, so each run is effectively a one-cell
> session. Likewise, in IPython trunk, if you do %reset, it nukes your
> namespace, gets a new history session, and sets the execution counter
> back to 1.

Ah, right.  So we were communicating correctly.  Yes, aleph and the 
single-cell server are doing exactly what you describe.  No state is 
preserved between calls.  That is simpler and lets us play with the 
design of the compute system and protocol before implementing a 
full-blown notebook.  It's also a lower barrier of entry for the public.


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