GOAL
  ns-prefix rdf = "http://www.w3.org/1999/02/22-rdf-syntax-ns#"
  ns-prefix dc  = "http://purl.org/dcelements/1.1"
  ns-prefix cal = "http://www.example.org/Calendar#"
  
  rdf:RDF[
    rdf:Description [
      attributes{rdf:about {"http:/www.example.org/Calendar/calendar.html"}},
        cal:events [
          rdf:Bag [
            all var Events,
        ]
      ]
    ],
    
    all var Event,
    all var Dates
  ]

FROM
  Events [
    EventList [var Events],
    Event[var Event],
    Date [var Dates]
  ] 
  
END


CONSTRUCT
  ns-prefix rdf ="http://www.w3.org/1999/02/22-rdf-syntax-ns#"
  ns-prefix dc  ="http://www.w3.org/1999/02/22-rdf-dyntax-ns#"
  ns-prefix cal ="http://www.example.org/Calendar#"
  
  Events[
    EventList [
      rdf:li [attributes{rdf:resources{var Summary}}]
    ],

    Event[
      rdf:Description[
        attributes{rdf:about{var Summary}},        

        optional cal:date[
          attributes{rdf:nodeID{var Date}}
        ],
        optional dc:title[var Titel],
        optional cal:summary[var Summary],
        optional cal:location[var Location],
        optional cal:contact[var Contact],
        
      ]
    ],
    
    Date[
      rdf:Description[
        optional attributes{rdf:nodeID{var Date}},
        optional cal: duration[var Duration],
        optional cal:startday[var Start],
        optional cal:starttime[var StartTime],
        
        optional cal:endday[var End],
        optional cal:endtime[var EndTime],
        optional cal:starttimezone[var EndZone],
        optional cal:endtimezone[var StartZone],
        optional cal:frequency[var Frequency],
     

      ]
    ]
  ] 
FROM
  in {
    resource ["file:Sprechstunde.html","html"],
      html [[
         body {{
          desc /.*/ {{
            attributes {class{"vevent"}},
            optional desc /.*/{{

              optional desc /.*/ {{
                attributes {class{/\s*summary\s*/}},
                var Titel
              }},
            
              optional desc /.*/{{
                attributes {class{/\s*summary\s*/}, title{var Titel}},
              }},
          
              optional desc /.*/{{
                attributes{class{"description"}},
                var Summary
              }},
           
              optional desc /.*/{{
                attributes{class{"duration"}, title{var Duration}},
              }},
              
              optional desc /.*/{{
                attributes{class{"location"}},
                var Location
              }},
              
              %optional desc /.*/{{
              %  attributes{class{"freq"}, title{var Frequency}},
              %}},
                               
              optional desc /.*/{{
                attributes{class{"dtstart"}, title{/^(var Start ->[0-9]{4}-?[0-9]{2}-?[0-9]{2})T(var StartTime ->[0-9]{2}:?[0-9]{2}(:?[0-9]{2})?)(var StartZone ->(Z|(-|\.+)[0-9]{2}:[0-9]{2}:[0-9]{2}))/}},
                var Date
              }},
             
              optional desc /.*/{{
                attributes{class{"dtstart"}, title{/^(var Start ->[0-9]{4}-?[0-9]{2}-?[0-9]{2})T(var StartTime ->[0-9]{2}:?[0-9]{2}(:?[0-9]{2})?)/}},
                var Date
              }},            
            
              optional desc/.*/{{
                attributes{class{"dtend"}, title{/^(var End ->[0-9]{4}-?[0-9]{2}-?[0-9]{2})T(var EndTime ->[0-9]{2}:?[0-9]{2}(:?[0-9]{2})?)(var EndZone ->(Z|(-|\.+)[0-9]{2}:[0-9]{2}:[0-9]{2}))/}},
              }},
 
              optional desc/.*/{{
                attributes{class{"dtend"}, title{/^(var End ->[0-9]{4}-?[0-9]{2}-?[0-9]{2})T(var EndTime ->[0-9]{2}:?[0-9]{2}(:?[0-9]{2})?)/}},
              }},
            
            }},

              optional desc /.*/{{
                attributes{class{/\s*url\s*/},href{var Contact}},
              }},
            }},
          }}
      }}
    ]]
  } 
END