08-229r1
To: J3
From: Van Snyder, originally Michael Ingrassia
Subject: Public Comment J32015
Date: 2008 August 11

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

Commenter: Robert Corbett
Subject: "assumed constraints for names"

Some time ago, I had an e-mail correspondence with a
member of the committee who asserted that the statement

     In order to minimize the number of additional
     syntax rules and convey constraint information,
     the following rules are assumed.

in Section 1.6.5 meant that if an xyz-name appeared in
a syntax rule, an assumed constraint required the name
to be the name of an xyz.  I pointed out that
constraint C101 explicitly said when an implicit
constraint should be assumed, and that because there
was no corresponding constraint for names, there were
no assumed constraints for names, except, of course,
for scalar-names.  If my interpretation is wrong, a
constraint similar to constraint C101 should be added
for xyz-names.

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

J3 response:

Requiring <xyz-name> to be the name of an <xyz> would not work for at
least two reasons.  First, there is frequently no syntax term <xyz>, for
example, there is no term <local> to which <local-name> could refer.
Second, there are cases where an implicit constraint would be
inappropriate, for example in R438 where an implicit constraint would
require the <component-name> in the definition of <component-decl> to be
the name of a component.  Where a constraint is required, one appears
explicitly, e.g. C437.