anchor.diff:      ?line true = true orelse false,
       ?line true = false orelse true,
       ?line false = false orelse false,
  +
  +    ?line true = ?GUARD(true orelse true),
  +    ?line true = ?GUARD(true orelse false),
  +    ?line true = ?GUARD(false orelse true),
  +    ?line false = ?GUARD(false orelse false),
   
       ?line true = true orelse glurf,
       ?line true = true orelse exit(exit_now),
  
positive.code: 
     ok.
  
  t_andalso(Config) when is_list(Config) ->
      Bs = [true,false],
      Ps = [{X,Y} || X <- Bs, Y <- Bs],
  
negative.code:     ?line false = true andalso false,
      ?line false = false andalso true,
      ?line false = false andalso false,
  
      ?line true = ?GUARD(true andalso true),
      ?line false = ?GUARD(true andalso false),
      ?line false = ?GUARD(false andalso true),
      ?line false = ?GUARD(false andalso false),
  
      ?line false = false andalso glurf,
      ?line false = false andalso exit(exit_now),
  