P11e2: type labels

[Ed Barkmeyer]

Jochen,

My 2 cents:

Penny 1.  The purpose of "type labels" is to be the parameter names for
"parametrized types".  And that in turn serves only one function in 
Express -- to say that the types of two objects with parametrized types 
are *the same*.  If there is a value to being able to say this for an 
attribute of an ABSTRACT ENTITY, then we should reverse the decision on 
UK-9.  Otherwise it could be syntactically permitted, but redundant -- 
it does not and cannot say anything useful.

I think there are situations in which it is useful to say that two 
attributes, or an attribute and the base type of an aggregate, have the
same actual type, even though they are both declared GENERIC_OBJECT,
for example.  On the other hand, it is also possible to declare this
in a WHERE clause in the ABSTRACT ENTITY declaration.  For formal 
parameters and local variables, there is no WHERE clause, so the
"type label" mechanism was created for that purpose.  So for ABSTRACT
ENTITY, "type labels" are a redundant but useful mechanism, and we
can decide either way.

Penny 2.  I put on my ISO procedures hat and ask why this is sent to WG11.
Unlike the version labeling and E2-E1 mapping annex, which affect other
WG11 projects, this is an E2 Editing Committee issue (an Express project
issue only).  You are suggesting we review the decision on UK-9.  From an
email discussion in the WG generally, how will we establish consensus on 
the decision?

-Ed

P.S. I disagree with Bernd in a minor way:  "Procedures and functions"
are not two cases, but one.  And there are many special rules for that
case.  One should not be "astonished" if the rules for entity 
declarations and the rules for "algorithm" declarations are different.
I do think Bernd is right that they are both (sometimes) "templates".

-- 
Edward J. Barkmeyer                       Email: edbark at nist.gov
National Institute of Standards & Technology
Manufacturing Systems Integration Division
100 Bureau Drive, Mail Stop 8260          Tel: +1 301-975-3528
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