private methods restricted to self?

[Marc Herbert <marc.herbert.1@ml.free.fr>]

On Tue, 22 Mar 2005, Remi Vanicat wrote:

> > I don't understand why my private subupdater is "made public implicitly"

> In ocaml, you can only call a private method on self. super#forward
> is not self, so you cannot call the color_forward method on it.

Indeed! This other example, without any subclass, is even more
surprising:

 class functional_point =
   object(self)
     val x = 0
     val y = 0
     method private bump_x = {< x = x + 1 >}
     method private bump_y = {< y = y + 1 >}

     method private bump_both = self#bump_x#bump_y
   end

 Warning: the following private methods were made public implicitly:
   bump_y



> In ocaml, you can only call a private method on self. super#forward
> is not self, so you cannot call the color_forward method on it.

Thanks a lot for the reasoning. But I still don't get the rationale.
Could I find the answer in Jerôme Vouillon's "an object calculus with
views"? Elsewhere? Thanks in advance.


About the reference documentation
---------------------------------

However ignorant are my questions above, I nevertheless think the
documentation is not clear about this whole issue.

To find this self#private restriction you have to dive into section
'6.9.2 Class expressions'. Unfortunately you may never go so far since
the more user-friendly '3.6 Private methods' section gives the less
restrive, more usual definition:

  "Private methods are methods that do not appear in object
  interfaces. They can only be invoked from other methods of the same
  object."

which made me think I knew enough about 'private' and prevented me to
look further.

Section '6.9.1 class types' also states:

  "The flag private indicates whether the method can be accessed from
  outside the class."

Coming from another OO-language, it's hard to understand "outside" as
"restricted to self".

So as a conclusion I find the manual at least confusing on this, if
not erroneous. Is it?

By the way, maybe some extra comment in the Warning message above
would not hurt either.


-- 
So einfach wie möglich. Aber nicht einfacher -- Albert Einstein