anchor.diff:  
   // 11. Event Declaration
   eventDeclaration
  -    : 'event' eventTypeDeclaration Identifier? parametersList
  +    : 'event' eventTypeDeclaration Identifier? parametersList delimiter
       ;
   
   eventTypeDeclaration
       : 'type'
       | creatorType
       ;
  -	
  +
   creatorType
       : 'create'
       | 'destroy'
       ;
  +
  +// 12. Event Implementation
  +eventImplementation
  +    : eventImplementationHead eventImplementationBody eventImplementationEnd
  +    ;
  +
  +eventImplementationHead
  +    : 'event' eventImplementationHeadType? eventImplementationHeadId? eventImplementationClosure parametersList?
  +    ;
  +
  +eventImplementationHeadType
  +    : 'type' dataTypeName
  +    ;
  +
  +eventImplementationHeadId
  +    : Identifier '::'
  +    ;
  +
  +eventImplementationClosure
  +    : Identifier
  +    | 'open'
  +    | 'close'
  +    ;
  +
  +eventImplementationBody 
  +    : statement*?
  +    ;
  +
  +eventImplementationEnd
  +    : 'end' 'event' delimiter
  +    ;    
  +	
   
   parametersList
       : '(' parametersDeclarators? ')'
  
positive.code:     | functionImplementation
      | onImplementation
      | eventDeclaration
     // | eventImplementation
      ;
  
  // 1. Forward Declaration
  
negative.code:     |   'DATE'
      |   'DATETIME'
      |   'DECIMAL'
      |   'dec'
      |   'DOUBLE'
      |   'integer'
      |   'int'
      |   'long'
      |   'longlong'
      |   'real'
      |   'string'
      |   'TIME'
      |   'UNSIGNEDINTEGER'
      |   'UINT'
  