From mboxrd@z Thu Jan  1 00:00:00 1970
X-Spam-Checker-Version: SpamAssassin 3.4.5-pre1 (2020-06-20) on
	ip-172-31-74-118.ec2.internal
X-Spam-Level: 
X-Spam-Status: No, score=-0.0 required=3.0 tests=BAYES_20 autolearn=ham
	autolearn_force=no version=3.4.5-pre1
Date: 12 Jul 91 22:17:57 GMT
From: munnari.oz.au!ariel!ucsvc.ucs.unimelb.edu.au!phillip.edu.au!x01233@uunet.
uu.net
Subject: Discriminants & limited privates - yuk?
Message-ID: <1991Jul12.171757.10257@phillip.edu.au>
List-Id: <comp.lang.ada>

Hello.


I have a question -  just HOW do i assign a value to a record with a
discriminant and a limited private component?

As I wish to set the value of the discriminant I have to use an aggregate(?),
which requires specifying values for all the components. The catch is that 
one component is limited private, and they can't appear in aggregates,
can they?


The procedure set (see below) must decide the value of the discriminant
(preferably the parameter would be an 'out' parameter,but that's a no-no) so 
its not acceptable to say that the discriminant should already have the 
required value.


Code that won't compile shown below...
---------------------------------------------------------------------------
-- define a limited private type and constant.

package lp is
	type blob is limited private;
	
	jelly	:constant blob;

private
	type blob is new integer;
	jelly	:constant blob:=42;
end lp;

---------------------------------------------------------------
with lp;	use lp;

procedure test is

	type enum_type is (a,b,c);

	type discriminant_record(discriminant:enum_type:=a) is
		record
			case discriminant is
			when a=>	
				item	:blob;
			when others=>
				null;
			end case;
		end record;


	item	:discriminant_record;

	---------------------------------------------------------------
	procedure set(	value	:in out	discriminant_record) is
	begin
		value:=(a,jelly);

			^^^^^^^^ Of course assignment is not available
				 for limited private types, so this is 
				 a no-no, but just how does 'value' get
				 a value?

	end;


begin
	set(item);
end;


------------------------------------------------------------------------------

Thanks in advance...


Dale.



------------------------------------------------------------------------
Dale Stanbrough			|
Phillip Institute of Technology	|
Melbourne, Australia		|
				|
dale@phillip.edu.au		|