anchor.diff:      ;
   
   methodExpression
  -    : implicationExpression (methodOrParameterName specialFunctor)*
  +    : implicationExpression 
  +      (methodOrParameterName specialFunctor | 'case' '(' expression ')' specialFunctor)*
       ;
   
   methodOrParameterName
  
positive.code:     ;
      
  positionalArguments
      : '(' (assignable (',' assignable)*)? ')'
      ;
  
  formalParameters
  
negative.code:     ;
  
  forIterator
      : formalParameter containment
      ;
      
  containment
      : 'in' expression
      ;
      
  doWhile
  