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From: Brian May <bam@snoopy.apana.org.au>
Newsgroups: comp.lang.ada
Subject: Re: Ada Popularity: Comparison of Ada/Charles with C++ STL (and
 Perl)
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Date: Sat, 02 Oct 2004 20:00:05 +1000
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Date: 2004-10-02T20:00:05+10:00
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>>>>> "K" == K  <slatyb@yahoo.com> writes:

    K> dbmap<Order> order_map;

    K> order_map.insert("ORDER.NUMBER", &Order::number)
    K> .insert("ORDER.CUSTOMER", &Order::customer_number)
    K> .insert("ORDER.ACCEPTED", &Order::acceptance_date)
    K> .insert("ORDER.PROMISED", &Order::promised_ship_date)
    K> ...

    K> and then be able to write:

    K> Order order;
    K> order_map.read(dbreader, order);
    K> order.promised_ship_date = ship_date(order.line_items);
    K> order_map.update(dbconnection, order);

Hmmmm... Thinking aloud: One approach that might work, at least for
some applications:

declare
        type Index_Type is (Number, Customer_Number, Acceptance_Date,
                   Promised_Ship_Date, ...);
begin
        insert(Order_Map, Number);
        insert(Order_Map, Customer_Number);
        insert(Order_Map, Acceptance_Date);
        insert(Order_Map, Promised_Ship_Date);
        ...     
end;

...          

declare      
        type Order is array (Index_Type) of ????
begin
        Read(Order_Map, dbreader, Order);
        Order(Promised_Ship_Date) := ship_date(order.line_items);
        Update(Order_Map,dbconnection, Order);
        ...
end;

(not tested; syntax may not be exactly correct)

The obvious problem with this is that all values need be the same
type. I am not sure if your code has this limitation or not.

Perhaps you could solve this with using a tagged type and
inheritance. I have a vague feeling this won't work; you can't have an
array of unconstrained types...
-- 
Brian May <bam@snoopy.apana.org.au>