anchor.diff:   */
   tree grammar SparqlT; 
   
  -options { 
  +options {
   tokenVocab=Sparql; // reuse token types
   ASTLabelType=CommonTree; // $label will have type CommonTree
   output=template; //template;
  
positive.code: 
  numericLiteral
      : u=numericLiteralUnsigned -> numericLiteral(numericLiteralUnsigned={$u.st})
      | p=numericLiteralPositive -> numericLiteral(numericLiteralUnsigned={$p.st})
      | n=numericLiteralNegative -> numericLiteral(numericLiteralUnsigned={$n.st})
      ;
  
  numericLiteralUnsigned
  
negative.code:     ;
  
  groupOrUnionGraphPattern
      : ^(UNION  g1=groupOrUnionGraphPattern g2=groupGraphPattern) -> groupOrUnionGraphPattern(unionGraphPattern={$g1.st}, groupGraphPattern2={$g2.st})
      | g=groupGraphPattern -> groupOrUnionGraphPattern(groupGraphPattern1={$g.st})
      ;
  
  filter
  