mapnik/tests/visual_tests/styles/text-line-wrap.xml

<!DOCTYPE Map>
<Map background-color="#b5d0d0" srs="+proj=longlat +ellps=WGS84 +datum=WGS84 +no_defs" minimum-version="0.7.2">
    <Style name="1">
        <Rule>
            <TextSymbolizer
                size="15"
                dy="-5"
                allow-overlap="true"
                face-name="DejaVu Sans Book"
                wrap-width=".1"
                repeat-wrap-character="[repeat-wrap-character]"
                wrap-character="[wrap-character]"
                halo-radius="1">[label]</TextSymbolizer>
            <PointSymbolizer allow-overlap="true" />
        </Rule>        
    </Style>

    <Layer name="point" srs="+proj=longlat +ellps=WGS84 +datum=WGS84 +no_defs">
        <StyleName>1</StyleName>
        <Datasource>
            <Parameter name="inline">

            {
                "type": "FeatureCollection",
                            
                "features": [
                
                    { "type": "Feature", 
                        "properties": {
                            "label": "this,that",
                            "wrap-character":",",
                            "repeat-wrap-character":true
                        },
                        "geometry"  : { "type": "Point", "coordinates": [ 2.5, 2.5 ] }
                    },
                    { "type": "Feature", 
                        "properties": {
                            "label": "this-that",
                            "wrap-character":"-",
                            "repeat-wrap-character":true
                        },
                        "geometry"  : { "type": "Point", "coordinates": [ 0, 5 ] }
                    }
                ]
            }
            
            </Parameter>
            <Parameter name="type">geojson</Parameter>
        </Datasource>
    </Layer>

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

    <Style name="frame">
        <Rule>
            <PointSymbolizer />
        </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
-1,-1
6,-1
-1,6
6,6
            </Parameter>
        </Datasource>
    </Layer>

</Map>