Re: Some additional obscure questions...

["Randy Presuhn" <randy_presuhn@mindspring.com>]

Hi -

> From: "Bob Natale" <Bob.Natale@AppliedSNMP.com>
> To: "Randy Presuhn" <randy_presuhn@mindspring.com>
> Cc: <mibs@ops.ietf.org>
> Sent: Thursday, February 06, 2003 11:37 AM
> Subject: Re: Some additional obscure questions...
...
> That is, the possible value for any DEFVAL clause
> of any OBJECT-TYPE definition is any value from
> the set of legal values according to the SYNTAX
> clause of that definition.  Since the SYNTAX
> clause defines the set (of values), the designation
> of any value among that set is not a "forward
> reference".

From a compiler / language design perspective, it
is a forward reference since the value cannot be
computed until more input is processed.  Indeed,
the compiler won't even know whether such a DEFVAL
is of the correct data type until that subsequent object
definition has been processed.

> In my view, the meaning of "forward reference"
> that is central to this discussion refers to a
> specification in the naming hierarchy of the MIB
> that is not rooted in the predecessor  portion
> of the MIB (modulo de jure standard starting
> points).  (Note that the use of "the MIB",
> rather than "a MIB" is deliberate there.)
...

I think that definition is a bit too narrow.  For purposes
of a MIB compiler, resolving references is not limited
to the registration of a defintion, but also resolution
of the contents of that definition (e.g. the OBJECTS
mentioned in a NOTIFICATION-TYPE).   Since a
compiler needs to be able to cope with forward
references for the various cases already brought up
in this thread, limiting the ability to have forward
references in the MODULE-IDENTITY would, in my
view, make things more complicated rather than
simpler.  (I.e., one would need to implement two
OID value resolution algorithms rather than one.)

Randy