<table dojoType="dojox.grid.DataGrid">
  <thead>
    <tr>
      <th field="id">ID</th>
      <th field="contact.name">Name</th>
      <th field="contact.tel">Telephone</th>
      <th field="contact.birthdate.time">Birthday</th>
    </tr>
  </thead>
</table>

[{
'id':1,
'contact':{
  'name':'Doh',
  'firstname':'John',
  'tel':'123-123456',
  'birthdate':{
    'javaClass':'java.sql.Timestamp',
    'time':1234567893434}}
}]

<table dojoType="dojox.grid.DataGrid">
  <thead>
    <tr>
      <th field="id">ID</th>
      <th field="contact" get="myGrid.getContactName">Name</th>
      <th field="contact" get="myGrid.getContactTel">Telephone</th>
      <th field="contact" get="myGrid.getContactBirthdateTime">Birthday</th>
    </tr>
  </thead>
</table>

myGrid.getContactName = function(colIndex,item){
  return item.name;
};

myGrid.getContactName = function(colIndex,record){
  if(record)return record.contact.name;
  else return null;
};

dgc._Base.markupFactory = function(node, cellDef){
var d = dojo;
...
var comparator = d.trim(d.attr(node,"comparator")||"");
if(comparator){
  cellDef.comparator = dojo.getObject(comparator);
}
...
}

getSortProps:function(){
...
return[{attribute:c.field,descending:desc,comparator:c.comparator}];
}

function execute(array){
    // execute the whole query, first we filter
    var results = dojo.filter(array, query);
    // next we sort
    if(options && options.sort){
        results.sort(function(a, b){
            for(var sort, i=0; sort = options.sort[i]; i++){
                var aValue = a[sort.attribute];
                var bValue = b[sort.attribute];
                if (aValue != bValue) {
                    // changed Part start
                    if(options.sort[i].comparator){
                        return !!sort.descending == options.sort[i].comparator(aValue,bValue) ? -1 : 1;
                    }
                    else{
                        return !!sort.descending == aValue > bValue ? -1 : 1;
                    }
                    // changed Part end
                }
            }
            return 0;
        });
    }
    ...
    return results;
}

...
<td field="myArray" get="getsNameFromArray" comparator="comparesNames">Name</td>
...

compareNames = function(a,b){
  return a.name > b.name;
}

getNamesFromArray= function(idx,record){
  return record.myArray.name;
}

...
<th field="contact" get=myGrid.getContactName>Name</th>
...