mapnik/tests/data/good_maps/text_breaks.xml

<!DOCTYPE Map>
<Map background-color="#b5d0d0" srs="+init=epsg:4326" minimum-version="0.7.0">
    <Style name="1">
        <Rule>
            <Filter>([label]='center')</Filter>
            <TextSymbolizer name="'one&#10;two&#10;three'" size="10" dy="-5" face-name="DejaVu Sans Book" wrap-character="," wrap-width="1" halo-radius="1"/>
            <PointSymbolizer/>
        </Rule>
        <Rule>
            <ElseFilter/>
            <TextSymbolizer name="[label]" size="10" dy="-5" face-name="DejaVu Sans Book" wrap-character="," wrap-width="1" halo-radius="1"/>
            <PointSymbolizer/>
        </Rule>        
    </Style>

    <Layer name="point" srs="+init=epsg:4326">
        <StyleName>1</StyleName>
        <Datasource>
            <Parameter name="string">

            {
            
            "type": "FeatureCollection",
            
            /* comment */
            
            "features": [
            
                { "type": "Feature", 
                
                    "properties": { "x": 0, "y": 0, "label": "0\n0" },
                    "geometry"  : { "type": "Point", "coordinates": [ 0, 0 ] }
                },
                { "type": "Feature", 
                
                    "properties": { "x": 5, "y": 5, "label": "5\n5" },
                    "geometry"  : { "type": "Point", "coordinates": [ 5, 5 ] }
                },
                { "type": "Feature", 
                
                    "properties": { "x": 0, "y": 0, "label": "0,5" },
                    "geometry"  : { "type": "Point", "coordinates": [ 0, 5 ] }
                },
                { "type": "Feature", 
                
                    "properties": { "x": 5, "y": 0, "label": "5,0" },
                    "geometry"  : { "type": "Point", "coordinates": [ 5, 0 ] }
                },
                { "type": "Feature", 
                
                    "properties": { "x": 2.5, "y": 2.5, "label": "center" },
                    "geometry"  : { "type": "Point", "coordinates": [ 2.5, 2.5 ] }
                },
                
                ]
            }
            
            </Parameter>
            <Parameter name="layer_by_index">0</Parameter>
            <Parameter name="type">ogr</Parameter>
        </Datasource>
    </Layer>

</Map>