Re: How to use associative arrays in Ada 2005?

[Simon Wright <simon@pushface.org>]

"snoopysalive" <matthias.kistler@gmx.de> writes:

> Nation    | Family Name   |  Name               | Age*
> ----------|---------------|---------------------|------
> German    | Goethe        | Johann Wolfgang     | 60
>           |               | Catharina Elisabeth | 80
>           |               | Johann Caspar       | 90
>           | Hesse         | Hermann             | 51
> Japanese  | Kusanagi      | Motoko              | 29
> American  | Ford          | Henry               | 45
>           |               | Harrison            | 41
> Finnish   | Torvalds      | Linus               | 35
> ----------|---------------|----------------------------

There's no reason I can see to use maps of maps *for this problem*. I
would use a hash function (Nation x Family_Name x Name) => Hash_Type
in a single map.

Matt, I see (A.18.4(5)) that Ada.Containers doesn't allow hash
collisions (which, if true, is demanding a lot of hash function
designers). If collisions aren't allowed we could go for an ordered
map based on 

    Left.Nation < Right.Nation 
    and then Left.Family_name < Right.Family_Name 
    and then Left.Name < Right.Name

or some likely-to-be-more-efficient order.