anchor.diff:  specialMethodArgument
       :(  methodOrParameterName | 'case' '(' expressions ')' ) specialFunctor 
       ;
  +
  +//if we want to support Smalltalk-style invocation with no arguments
  +/*methodExpression
  +    : implicationExpression specialMethodInvocation?
  +    ;
  +
  +specialMethodInvocation
  +    : methodOrParameterName ( specialFunctor specialMethodArgument* )?
  +    | caseMethodParameter specialFunctor specialMethodArgument*
  +    ;
  +
  +specialMethodArgument
  +    : ( methodOrParameterName | caseMethodParameter ) specialFunctor
  +    ;
  +
  +caseMethodParameter
  +    : 'case' '(' expressions ')'
  +    ;*/
   
   methodOrParameterName
       : LIDENTIFIER
  
positive.code:     ;
      
  instances
      : 'instances' instance (',' instance)* ';'
      ;
  
  instance 
  
negative.code: 
  // Lexer
  
  NATURALLITERAL
      : ('0' .. '9')('0' .. '9')*
      | '\'' HexDigit HexDigit HexDigit HexDigit '\''
      | '\'' HexDigit HexDigit '\''
  