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Re: Dragging nodes
- To: info-mcl
- Subject: Re: Dragging nodes
- From: email@example.com (Andrew L. M. Shalit)
- Date: 29 Aug 91 20:09:22 GMT
- Distribution: comp
- In-reply-to: firstname.lastname@example.org's message of 29 Aug 91 18:45:00 GMT
- Newsgroups: comp.lang.lisp.mcl
- Organization: Apple Computer Inc, Cambridge, MA
- References: <JAMESJ.91Aug29114500@bert.cs.byu.edu>
- Sender: email@example.com
In article <JAMESJ.91Aug29114500@bert.cs.byu.edu> firstname.lastname@example.org (JAMES JEREMIAH WAYNE ) writes:
I am new to MCL, so this message may very well display my ignorance. I
would like to represent an undirected graph in a window which is freely
alterable by the user. That is, I would like to let the user add and delete
nodes and edges as well as drag the nodes around to suit his/her fancy and
trail any associated edges as a node is dragged. This last is the problem.
MCL does not seem to have the functions I need to modify a button-dialog-item
sufficiently to behave in this manner, and while attempting to design a custom
dialog-item, I discovered that defpascal, which I need to write the definition
function, appears to be crippled. It works fine when writing functions with
no parameters, but when I include even one parameter, the compiler complains
about its type. Does anyone have any ideas on how I can get around these
problems, or possibly an entirely different approach to implementing this?
1) You shouldn't need to do anything with defpascal.
2) If there is a problem subclassing button-dialog-item, could report this
as a bug?
3) Even if you can't subclass button-dialog-item, you should just be able
to subclass dialog-item. The button-dialog-item class doesn't add very
much behavior. To create a subclass of dialog-item, you need to define
a small set of methods, which are described in the manual.
4) The syntax of defpascal is described incorrectly in the manual. I don't
know the correct syntax, but I'm sure someone else reading this does.
Hope this helps.