anchor.diff:     ;
   
   verb
  -   : name ('(' expressionlist ')')?
  +   : name ('(' expressionlist? ')')?
      ;
   
   property
  
positive.code:    | real
     | list
     | DOLLAR
     ;
  
  functioninvocation
  
negative.code:    ;
  
  forblock
     : 'for' name 'in' expression statement + 'endfor'
     ;
  
  tryblock
  