[R-gui] Interfaces between GUIs and R

[Philippe Grosjean]

Byron Ellis wrote:
>I was curious how you were going to handle the graphics devices... Are
>you somehow capturing the output from the devga device under the
>Windows platform?

I capture the graph device window, i.e., I display it in my own application
instead of in its original place but R is still responsible directly of
(re)drawing its content. This way, I do not need to exchange large amounts
of data between the backend and the frontend (indeed, there are no exchanges
at all!) and all functionalities provided by the original R graph device are
still available in SciViews, like copy metafile/bitmap to the clipboard,
save the graphs directly in different formats, save and restore to and from
a variable in the R user workspace and management of a graph history that is
specific to the Windows version of R.

>As far as I can determine from working with the C APIs, the OpenMath
>and MathLink protocols are quite similar, though they use a slightly
>different protocol syntax you can generate a complete mapping from one
>to the other:
>	MLPutInteger -> OMputInt32
>	MLPutReal     -> OMputFloat64
>	MLPutSymbol-> OMputSymbol (though OpenMath seems to suport a namespace
>mechanism they call "CD"s for some reason)

Then, as you suggest, OpenMath could be an excellent solution to interface
R. However, R  being a statistical package there are few needs in
representing complex mathematical notation. Even, R uses its own notation
for statistical models (formulas). I wonder if and how this could be easily
and automatically translated in a more traditional mathematical notation,...
and even if this would be desirable?!

>There's no function for MLPutFunction, rather they use a more open
>ended mechanism (OMputApp,OMputSymbol,...,OMputEndApp) eliminating the
>need to send an argument count. This is slightly more difficult to
>serialize. There are also other elements for sending richer structures
>(to simulate MathLink arrays and whatnot) via OMputObject and
>OMputEndObject. This makes it pretty easy to build lists and arrays.
>You can also send opaque byte objects much like MathLink.

>The API has mechanisms for socket transfer (*NIX,Win32) and *NIX
>sockets (*NIX only, of course) with either binary or "XML"
>serialization (though it doesn't produce a document that conforms to
>the XML standard... it just happens to use an XML-like structure that
>you could stick into an XML document)

Do you intend to initiate a project for making an OpenMath interface for R?
If yes, I would like to take part of it, and ultimately include these
features to the SciViews R plug.

>Admittedly, the website and most of the papers seem to talk about these
>complex server set ups where various servers offer a variety of
>services dispatched through a hub of some sort, but the reality of the
>situation is the API is basically a MathLink clone (which is fine,
>since it was exactly what I expected it to be :-))

I have looked a little closer to it, and indeed yes, it is closer to
MathLink as it looks like when you first browse their web site.

Best Regards,

Philippe Grosjean

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( ( ( ( (       Dr. Philippe Grosjean
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