title: join two expressionList with "or" or "and"
body: <p>I'm having some trouble to join 2 expressionList with an "or".
  This is an example of what I'm doing:</p>
  
  <pre><code>RelationGroup prg =...
  ExpressionList&lt;User&gt; exp = User.find.where();
  List&lt;ExpressionList&lt;User&gt;&gt; expressions = new ArrayList&lt;ExpressionList&lt;User&gt;&gt;()
  List&lt;String&gt; relations = new ArrayList&lt;String&gt;()
  
  while(prg != null){
  
      if(prg.prevGroupRelation != null)
          relations.add(prg.prevGroupRelation);
  
      for(RelationAtt pra : prg.prAtt){
          if(pra.rel.equals("eq"))
              exp = exp.eq(pra.name, pra.value1 );
          else if(pra.rel.equals("lt"))
              exp = exp.lt(pra.name,   pra.value1);
          else if(pra.rel.equals("gt"))
              exp = exp.gt(pra.name,  pra.value1);
          else if(pra.rel.equals("bw"))
              exp = exp.gt(pra.name,  pra.value1).lt(pra.name,  pra.value2);
      }
  
      expression.add(exp);
      prg=prg.nextPRG();
      exp = new ExpressionList&lt;User&gt;(); 
  }
  
  for(i=0;i&lt;expressions.count-1; i++)
      if(relations[i].equals("or")){
          //ToDo: (expressions[i]) or (expressions[i+1])                      
      }else{
          //ToDo: (expressions[i]) and (expressions[i+1])                     
      }
  </code></pre>
  
  <p>I need to have something like:</p>
  
  <pre><code>select *
  from tableName
  where (varName1=value and varName2=value) or (varName3) or (varName4=value and varName5=value) 
  </code></pre>
  
  <p>This is fully dynamic so the varNames can be any of the currently existing(because the queries are build by the user using a web page interface), so i can't use raw SQL that easily. Now i need to join prevExp and exp with an or/and and replace exp. The <code>ExpressionList.or(exp, exp)</code> receive 2 Expressions.
  Any help with this is appreciated thank you</p>