Comment by blksv

I strongly support your point, but the example is still sand-in-the-eyes for me. I hold that one symbol should not alter the semantics of a program and there should never ever be sequences of one-symbol syntactic elements.

In an Ada-like language, it would be something like

  generic
      type Path_Type implements As_Path_Ref;
      type Reader implements IO.File_Reader;
  function Read(Path: Path_Type) return Reader.Result_Vector_Type|Reader.Error_Type is
      function Inner_Read(P: Path) return Read'Result_Type is
      begin
          File:  mutable auto := try IO.Open_File(P);
          Bytes: mutable auto := Reader.Result_Vector_Type.Create();
          try Reader.Read_To_End(File, in out Bytes);
          return Bytes;
      end;
  begin
      return Inner_Read(Path.As_Ref());
  end Read;