From: Matthew Heaney <matthew_heaney@acm.org>
Subject: Re: Generic type parameters
Date: 1999/06/15
Date: 1999-06-15T00:00:00+00:00 [thread overview]
Message-ID: <m37lp6cm5h.fsf@mheaney.ni.net> (raw)
In-Reply-To: 7k3ae5$stk$1@nnrp1.deja.com
On 14 Jun 1999 16:25, dommo1234@my-deja.com wrote:
> generic
> type TypeX is private;
> package Example is
> function One(..) return TypeX;
> function Two(..) return TypeX_A;
> function Three(..) return TypeX_AC;
> end Example;
>
> ... where 'TypeX_A' needs to be "access all TypeX"
> and 'TypeX_AC' needs to be "access constant TypeX".
>
> The problem is that if I delcare the two types 'TypeX_A' and 'TypeX_AC'
> inside the generic, then any code containing variables that catch the
> values of functions 'Two' and 'Threee' inside my generic must be of type
> <generic inst>.Type_A etc. This is not very readable or convenient!
>
> The only (not so sensible) solution I can think of is provide the
> generic with 3 formal parameters, ie. TypeX, TypeX_A and TypeX_AC ....
>
> Does anyone have a neater solution to this??
I don't know about "neater," but you can create another generic package
in which to declare the access types, and import an instantiation of
that package as a generic formal package:
generic
type TypeX is private;
package TypeX_Access_Types_G is
type TypeX_A is access all TypeX;
type TypeX_AC is access constant TypeX;
end;
with TypeX_Access_Types_G;
generic
with package TypeX_Access_Types is
new TypeX_Access_Types_G (<>);
use TypeX_Access_Types;
package Example is
<as above>
end;
next prev parent reply other threads:[~1999-06-15 0:00 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
1999-06-14 0:00 Generic type parameters dommo1234
1999-06-15 0:00 ` Matthew Heaney [this message]
1999-06-15 0:00 ` dommo1234
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