[kepler-dev] problems with annotations
Edward A. Lee
eal at eecs.berkeley.edu
Thu Oct 27 09:10:54 PDT 2005
A change request does not have to be a MoML string. In fact,
many of them are not. In particular, a change request is an
instance of ChangeRequest. MoMLChangeRequest is a subclass.
However, the "undo" mechanism in Vergil will only work if the
change request is an instance of MoMLChangeRequest. Thus,
if you make changes using ChangeRequest, they are not undone
by the undo command. There are many circumstances in which
this is OK.
At 01:45 AM 10/27/2005 -0700, Shawn Bowers wrote:
>The following comment may be coming from far left field, but I have
>never quite understood why a change request as it is currently defined
>in ptolemy requires the passing of a MoML XML string.
>In particular, it is confusing to me as a developer why I have to deal
>with *both* the object model of ptolemy/kepler as well as the
>serialization syntax of the part of the object model I'm
>instantiating or modifying.
>I think it would be more convenient to pass *objects* to change
>request, not XML serializations of the things I want to update.
>Does that make sense?
>Edward A. Lee wrote:
>>At 08:01 AM 10/26/2005 -0700, Christopher Brooks wrote:
>>>Your design of using EmptyChangeRequest seems reasonable, though
>>>it seems to point out a bug in the Ptolemy code.
>>I don't think it's a bug in the Ptolemy code.
>>The reason that EmptyChangeRequest works is that after
>>any change request, the model gets redrawn. This is
>>a very brute-force way to react to change requests,
>>and in fact is very costly (even changes that have no
>>visible side effects will trigger a redraw).
>>Thus, the real problem is long term: If we fix Ptolemy II
>>so that redraws occur only when necessary, then the
>>EmtpyChangeRequest will no longer do what you want...
>>Edward A. Lee
>>Professor, Chair of the EE Division, Associate Chair of EECS
>>231 Cory Hall, UC Berkeley, Berkeley, CA 94720
>>phone: 510-642-0253 or 510-642-0455, fax: 510-642-2845
>>eal at eecs.Berkeley.EDU, http://ptolemy.eecs.berkeley.edu/~eal
>>Kepler-dev mailing list
>>Kepler-dev at ecoinformatics.org
Edward A. Lee
Professor, Chair of the EE Division, Associate Chair of EECS
231 Cory Hall, UC Berkeley, Berkeley, CA 94720
phone: 510-642-0253 or 510-642-0455, fax: 510-642-2845
eal at eecs.Berkeley.EDU, http://ptolemy.eecs.berkeley.edu/~eal
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