Subject: The Unspecified Parameter Issue

From: Tom-PT Taylor <[email-masked]>
Date: Sat, 15 Apr 2000 21:22:54 -0500

We have an issue with the contradiction both within the generic rules of
section 7.1.1 concerning unspecified parameters, and between them and other
sections.  The problem comes about because at different times we want to do
the following, but each time we are using the same syntax:

(a) retain information already specified on a termination without having to
send it down again;

(b) use default or provisioned values for parameters rather than specify the
values explicitly;

(c) delete information previously specified on a termination.

For any specific item, it may make sense to say that only one of (a), (b),
or (c) will ever apply.  For instance, an omitted event or signal parameter
always means that the default or provisioned value should be used for that
parameter.  Unfortunately, I don't think we have spelled out our intent for
every parameter or property in the standard, and I'm concerned that we may
not be able to do so because we may find cases where we want to have more
than one of (a), (b), or (c) apply to the same item in different contexts.
I therefore propose that we give up on (a) (which is an optimization) and
make the following changes to existing text:

In the general rules of section 7.1.1, say that unless otherwise specified
in subsequent sections, omission of a parameter or property from a command
means that that parameter or property is given the special value "no value".
The MG may report an error if "no value" is inconsistent with the values of
other parameters and properties of the termination concerned.

Also say in section 7.1.1 that if CHOOSE is specified for a property or
parameter, the MG should substitute the default or provisioned value of that
parameter where there is no reason to provide a different value.

In the sections on event and signal descriptors, say specifically that
omission of a signal or event parameter causes that parameter to take on its
default or provisioned value.

Comments?

Tom Taylor
Phone and FAX: +1 613 736 0961
E-mail: [email-masked]