anchor.diff:      ;
   
   regexExpression
  -    : ^(REGEX (e+=expression)+) -> regexExpression(expression={$e})
  +    : ^(REGEX (e+=expression)+) -> regexExpression(type={$REGEX.text}, expression={$e})
       ;
       
   subStringExpression
  
positive.code:  */
  tree grammar SparqlT; 
  
  options {
  tokenVocab=Sparql; // reuse token types
  ASTLabelType=CommonTree; // $label will have type CommonTree
  output=template; //template;
  
negative.code: groupGraphPattern
      : ^(GROUP_GRAPH_PATTERN g=groupGraphPatternSub) -> groupGraphPattern(groupGraphPatternSub={$g.st})
      | ^(GROUP_GRAPH_PATTERN s=subSelect) -> groupGraphPattern(subselect={$s.st})
      | ^(GROUP_GRAPH_PATTERN GROUP_GRAPH_PATTERN) -> groupGraphPattern(attribute={""})
      ;
    
  groupGraphPatternSub
  