anchor.diff:  parenthesizedExpression : '(' expressionElementList? ')'  ;
   expressionElementList : expressionElement (',' expressionElement)*  ;
   expressionElement : expression | expressionElementIdentifier ':' expression  ;
  +// Swift Language Reference does not have "keyword"
   expressionElementIdentifier: identifier | keyword ;
   
   // GRAMMAR OF A WILDCARD EXPRESSION
  
positive.code: 
  identifier : Identifier | contextSensitiveKeyword ;
  
  keyword : 'convenience' | 'class' | 'deinit' | 'enum' | 'extension' | 'func' | 'import' | 'init' | 'let' | 'protocol' | 'static' | 'struct' | 'subscript' | 'typealias' | 'var' | 'break' | 'case' | 'continue' | 'default' | 'do' | 'else' | 'fallthrough' | 'if' | 'in' | 'for' | 'return' | 'switch' | 'where' | 'while' | 'as' | 'dynamicType' | 'is' | 'super' | 'self' | 'Self' | 'Type' | 'repeat' ;
  
  contextSensitiveKeyword :
   'associativity' | 'convenience' | 'dynamic' | 'didSet' | 'final' | 'get' | 'infix' | 'indirect' |
  
negative.code:  | attributes? sType
   | externalParameterName? localParameterName typeAnnotation '...'
   ;
  // Swift Language Reference does not have "keyword"
  externalParameterName : identifier | keyword | '_'  ;
  localParameterName : identifier | '_'  ;
  defaultArgumentClause : '=' expression  ;
  