Re: Beginners question: Compound types, how-to?

[Jeffrey Carter <spam.jrcarter.not@spam.not.acm.org>]

On 10/31/2010 03:00 PM, Mart van de Wege wrote:
>
> games-rpg-dnd.ads:
> --with Games.RPG;
> -- Ignore parent package for now, we don't need the
> -- utility functions yet.

Children always have visibility into the specs of their ancestors, so you never 
need to "with" said ancestors.

> with Games.RPG.DnD, Ada.Text_IO, Ada.Integer_Text_IO;
> use Games.RPG.DnD, Ada.Text_IO, Ada.Integer_Text_IO;
>
> procedure Test_Game is
>     C : Character;

You have 2 things named Character at this point: Standard.Character, an 
enumeration type, and Standard.Games.RPG.DND.Character, a record type. 
Standard.Character is directly visible, and the other is "use visible", visible 
due to a use clause. The rule is that something that is use visible cannot hide 
something that is directly visible. Since both can't be referenced by the simple 
name Character, this must refer to the one that is directly visible, 
Standard.Character.

Things are different for subprograms, which can be overloaded; then both may be 
visible and referred to by the simple name.

But it's usually a good idea for a beginner to avoid use clauses.

-- 
Jeff Carter
"Why, the Mayflower was full of Fireflies, and a few
horseflies, too. The Fireflies were on the upper deck,
and the horseflies were on the Fireflies."
Duck Soup
95