anchor.diff:      ;
   
   statements
  -    :   statement ( (NL | ';') statement)* NL*
  +    :   statement ( (NL | SEMI) statement)* NL*
       ;
   
   statement
       :   namespace
  -    |   enum_block
  +    |   enumeration
       |   if_block
       |   foreach_block
       |   while_block
  
positive.code:     ;
  
  expressions
      :   expression ( (NL | ',') expression)*
      ;
  
  expression
  
negative.code: DEBUG   :   'debug';
  DO      :   'do';
  ELSE    :   'else';
  ELIF    :   'elif';
  FOREACH :   'foreach';
  IF      :   'if';
  IN      :   'in';
  