mapnik/tests/visual_tests/styles/marker-path-expression.xml

<Map srs="+proj=longlat +ellps=WGS84 +datum=WGS84 +no_defs">

    <Style name="ellipse">
        <Rule>
            <MarkersSymbolizer file="../../data/svg/[FILENAME].[FILETYPE]" />
        </Rule>
    </Style>

    <Layer name="layer" srs="+proj=longlat +ellps=WGS84 +datum=WGS84 +no_defs">
        <StyleName>ellipse</StyleName>
        <Datasource>
            <Parameter name="type">csv</Parameter>
            <Parameter name="inline">
x,y,FILENAME,FILETYPE
2.5,2.5,rect2,svg
            </Parameter>
        </Datasource>
    </Layer>

    <!-- points to frame data view -->

    <Style name="frame">
        <Rule>
            <PointSymbolizer />
            <DebugSymbolizer />
        </Rule>
    </Style>

    <Layer name="frame" srs="+proj=longlat +ellps=WGS84 +datum=WGS84 +no_defs">
        <StyleName>frame</StyleName>
        <Datasource>
            <Parameter name="type">csv</Parameter>
            <Parameter name="inline">
x,y
0,0
5,0
0,5
5,5
            </Parameter>
        </Datasource>
    </Layer>
    
</Map>