Q: Dynamically testing type of any variable

Q: Dynamically testing type of any variable

[david scott gibson]

Hi.  Is there any way to determine the type of an arbitrary Ada95
variable at runtime?  Inside a generic unit, I'd like to test if a
generic formal has been instantiated with a scalar type, and then if
so, initialize it to some valid representation.  It doesn't appear
that the 'Class or 'Valid attributes help much since neither is
defined for all types.  Also, I'd prefer not using any exception
trickery to deal with this.  Any ideas?

Dave
--
dgibson@cis.ohio-state.edu

Re: Q: Dynamically testing type of any variable

[Norman H. Cohen]

In article <4ov0miINN99m@snoopy.cis.ohio-state.edu>,
dgibson@snoopy.cis.ohio-state.edu (david scott gibson) writes: 

|> Hi.  Is there any way to determine the type of an arbitrary Ada95
|> variable at runtime?  Inside a generic unit, I'd like to test if a
|> generic formal has been instantiated with a scalar type, and then if
|> so, initialize it to some valid representation.  It doesn't appear
|> that the 'Class or 'Valid attributes help much since neither is
|> defined for all types.  Also, I'd prefer not using any exception
|> trickery to deal with this.  Any ideas?

This is a peculiar requirement.  Can you give us a better idea of what
you are trying to accomplish?

If your template is doing things with objects of your generic formal type
that are improper for uninitialized scalars, and if a particular
invocation of a particular instance actually does these things to
uninitialized scalars, why do you want to mask the error behind an
arbitrary "valid" value?

--
Norman H. Cohen    ncohen@watson.ibm.com