Metadata in svg output

[Stuart Pullinger]

Hi,

I am writing an application to take the results of musical performance 
analysis and plot them above the score produced by Lilypond. I need to be 
able to trace which graphic elements in the svg file relate to which notes in 
the input file. Using svg also allows a certain amount of interactivity in 
the display which would be more difficult to achieve with ps/pdf.

Would it be possible to add support for metadata tags in Lilypond's svg 
output? An example:

% lilypond file
{
c' \svgmetadata {mynamespace notestarttime 0.12345}
}
% end

<!-- xml snippet !-->
<g 
    transform="translate(22.9263719527559, 18.8286614173228)">
    <text
        style="font-family:Emmentaler;
            font-style:20;
            font-size:4.0;
            text-anchor:west;"
        fill="currentColor">
        <tspan>
            <metadata>
                <mynamespace:notestarttime>
                0.12345
                </mynamespace:notestarttime>
            </metadata>
            &#xe127;
        </tspan>
    </text>
</g>
    
NB: According to the w3c SVG 1.1 spec 
(http://www.w3.org/TR/SVG11/metadata.html):
"The contents of the 'metadata' should be elements from other XML namespaces."

Thanks,
Stuart