'private' and Privacy

[Rick <rickduley@gmail.com>]

I have never fathomed out why we declare entities in packages to be
'private' and then have to go and tell the world what is in them.  I
would assume that 'private' has something to do with 'information
hiding' yet we expose what is 'private'.

I have:

   KEYPAD_ROWS_COUNT : constant Positive := 2;
   -- The number of rows on a keypad.

   KEYPAD_COLUMNS_COUNT : constant Positive := 2;
   -- The number of columns on a keypad.

   type Keys_Type is array
     (1 .. KEYPAD_ROWS_COUNT, 1 .. KEYPAD_COLUMNS_COUNT)
   of Gtk.Key_Button_Pkg.Gtk_Key_Button_Access;
   --Intermediate, addressable storage of keys for the keypad.

I am trying to find a way to ensure that the user only addresses items
in the array in the manner I provide rather than making use of the
information clearly visible about the range of the array.  I can use
functions instead of constants to define array range values but they
have to be fully declared before I define the array - and this exposes
that which I wish to remain private (the actual range).

Isn't this a contradiction in terms, or _is_ there a way to retain
'Privacy'?
--------------------------------------------
Rick Duley
North Perth,
Western Australia
http://rickduley.webs.com
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"Answers are easy;
         it's asking the right questions
                             which is hard."
The Doctor (Dr Who: The Face of Evil (1977)"