Re: Support for callbacks...

[Lars Clausen <lrclause cs uiuc edu>]

On Tue, 15 Jul 2003, Herman Bruyninckx wrote:
> What is the status of callbacks in the Dia roadmap?
>
> I mean, is it (or will it be) possible to let some dia actions call a
> user-defined function?
>
> For example, a callback on each (dis)connection event on the canvas
> gives a lot of possibilities to add user-specific functionality to
> Dia. (E.g., to check whether it has a meaning in the users'
> application context to connect two given objects together.)

That's funny, I was just thinking about that in the shower this morning.  A
callback function would allow both elements and connectors to decide
whether they will allow the connection, and if they do, make any changes
that are needed.

Unless, by 'user-defined function', you mean that the user can add a bit of
scripting to an object to be evaluated upon connection.  Given the above,
that could be added using the Python plugin, or any other plugin that
anyone cares to add.  Design/CPN has something slightly similar, annotating
connections with SML expressions that are evaluated during a simulation step.

-Lars

-- 
Lars Clausen (http://shasta.cs.uiuc.edu/~lrclause)| HÃrdgrim of Numenor
"I do not agree with a word that you say, but I   |----------------------------
will defend to the death your right to say it."   | Where are we going, and
    --Evelyn Beatrice Hall paraphrasing Voltaire  | what's with the handbasket?