anchor.diff:    ;
   
   small_stmt
  -  : (expr_stmt | print_stmt | del_stmt | pass_stmt | flow_stmt | import_stmt | assert_stmt)
  +  : (expr_stmt | print_stmt | stub_stmt | pass_stmt | flow_stmt | import_stmt | assert_stmt)
     ;
   
   expr_stmt
  
positive.code: OR: 'or';
  NOT: 'not';
  ASSERT: 'assert';
  DEL: 'del';
  PASS: 'pass';
  CONTINUE: 'continue';
  THROW: 'throw';
  FUNC: 'func';
negative.code:   ;
  
  throw_stmt
    : THROW test?
    ;
  
  // URLs refer to directory structure within sandbox or component, or to
  