anchor.diff:      | functionImplementation
       | onImplementation
       | eventDeclaration
  -   // | eventImplementation
  +    | eventImplementation
       ;
   
   // 1. Forward Declaration
  
positive.code:     |   'DATE'
      |   'DATETIME'
      |   'DECIMAL'
      |   'DEC'
      |   'DOUBLE'
      |   'INTEGER'
      |   'INT'
      |   'LONG'
      |   'LONGLONG'
      |   'REAL'
      |   'STRING'
      |   'TIME'
      |   'UNSIGNEDINTEGER'
      |   'UINT'
  
negative.code: 
  // 11. Event Declaration
  eventDeclaration
      : '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? ')'
  