anchor.diff:  
   patternConstraint: 'PATTERN' value ;
   
  -propertySettings: 'SETTINGS' simplestring ;
  +propertySettings: 'SETTINGS' SIMPLESTRING ;
   
   propertySettingsList: (propertyAndSettingPair)+ ;
   
   propertyAndSettingPair: propertyName '=' settingName ;
   
  -propertyName: psname ;
  -
  -settingName: psname ;
  +propertyName: PSNAME ;
  +
  +settingName: PSNAME ;
   
   durationRange: valueRange ;
   
  
positive.code: // Chapter 54 Encoding Control Sections
  encodingControlSections : encodingControlSection (WS encodingControlSections)* ;
  
  encodingControlSection: 'ENCODING-CONTROL' encodingreference encodingInstructionAssignmentList ;
  
  encodingInstructionAssignmentList: encodingreference ;
  
  encodingInstruction: encodingReference ;
  
  
negative.code: 	| parameterizedAssignment ;
  
  // Chapter 14 Referencing type and value definitions
  definedType: externalTypeReference | TYPEREFERENCE | parameterizedType | parameterizedValueSetType ;
  
  definedValue: externalValueReference | VALUEREFERENCE | parameterizedValue ;
  
  nonParameterizedTypeName: externalTypeReference | TYPEREFERENCE | XMLASN1TYPENAME ;
  
  externalTypeReference: MODULEREFERENCE '.' TYPEREFERENCE ;
  
  externalValueReference: MODULEREFERENCE '.' VALUEREFERENCE ;
  
  // Chapter 15
  
  // Chapter 16
  typeAssignment: TYPEREFERENCE '::=' type ;
  
  valueAssignment: VALUEREFERENCE type '::=' value ;
  
  xMLValueAssignment: VALUEREFERENCE '::=' xMLTypedValue ;
  
  xMLTypedValue
  	: '<' nonParameterizedTypeName '>' xMLValue '</' nonParameterizedTypeName '>'
  	| '<' nonParameterizedTypeName '/>' ;
  
  valueSetTypeAssignment: TYPEREFERENCE type '::=' valueSet ;
  
  valueSet: '{' elementSetSpecs '}' ;
  
  