anchor.diff:     ;
   
   describedecl
  -   : '@describe' (property | stringliteral) 'as' expression
  +   : '@describe' property 'as' expression
      ;
   
   contentsdecl
  
positive.code:    ;
  
  programdecl
     : '@program' name ':' name statement + '.'
     ;
  
  verbdecl
  
negative.code:    ;
  
  property
     : propertyname (('.' name) | '[' expression ']')*
     ;
  
  propertyname
     : name
     | stringliteral
     ;
  
  list
  