Re: [guppi-list] Re: Plot idl

[Havoc Pennington <rhpennin midway uchicago edu>]

On Thu, 17 Sep 1998, Dean Brettle wrote:
> 
> that make sense for the data.  If, for example, the data doesn't make
> sense as doubles, the doubles methods would just throw CoercionError. 
> Also, you don't really need the union anymore or the get_as_values() and
> set_as_values() methods anymore.  Callers would always use the other
> methods.
>

OK, I like this. The only disadvantage I see is that you have to give up
compile-time type checking; but it should be a fairly obvious error if
someone stuffs strings into a scatterplot. 
 
> BTW, I'm assuming that Row above is similar to Values from before.  I
> definitely like the name Row better than Values because it is singular,
> but you might want something which is less, err, directional. :)  How
> about something like Vector?  I don't know...just a thought.
>

Yes - Values was a dumb name. Vector is a good idea.
 
> I recommend exporting as little as possible to start while
> simultaneously ensuring that future additions can remain compatible.  To
> that end, I think you need something like a Values/Row/Vector interface,
> a generic Plot interface, and then derived interfaces for each Plot type
> you provide.  I have attached one possibility below.  I've changed
> Values/Row to Vector and added a VectorFactory interface which would be
> implemented by guppi for callers that do not provide their own Vectors.
>

Okie. I'm all for this; it also involves minimal initial work. :-) 

The remaining problem, for the IDL as well as Guppi, is handling arrays of
plots and overlaid plots simultaneously. Basically for each X axis, there
is a sequence of Vector pairs for each Y axis. When edited interactively
in arbitrary ways this gets real annoying. :-) The Vector pairs are one X
vector and one Y vector for each overlay.

> BTW, have you been following my discussion with Paolo on the gnumeric
> list or are you only subscribed to guppi-list?
> 

I'm only on guppi-list, but I'll check the archives.

Havoc