anchor.diff:   (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
    THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
   */
  -
   grammar ANTLRv3;
   
   grammarDef
  -   : DOC_COMMENT? ('lexer' | 'parser' | 'tree')? 'grammar' id ';' optionsSpec? tokensSpec? attrScope* action* rule_ +
  +   : DOC_COMMENT? ('lexer' | 'parser' | 'tree')? 'grammar' id ';' optionsSpec? tokensSpec? attrScope* action* rule_+
      ;
   
   tokensSpec
  -   : TOKENS tokenSpec + '}'
  +   : TOKENS tokenSpec+ '}'
      ;
   
   tokenSpec
  
positive.code:    ;
  
  rewrite_tree_alternative
     : rewrite_tree_element +
     ;
  
  rewrite_tree_element
  
negative.code:    ;
  
  alternative
     : element+
     ;
  
  exceptionGroup
     : (exceptionHandler)+ (finallyClause)?
     | finallyClause
     ;
  
  