Subject: Connect construct
From: Rick Reed (Rick.Reed#etsi.fr)
Date: Mon Jun 04 2001 - 08:21:44 GMT
Dear All,
Observation resulting from ETSI STF188 work.
A <connect area> (or in textual grammar a <connect part>) represents the
transition to be taken on exit from a composite state. It contains an
optional <connect list>, which defines the exits that lead to the
transition.
The <connect list> can be omitted, to denote and then denotes the unnamed
exit from the composite state, or it can be a list of <\underline{state exit
point} name>s or an <asterisk>.
If the composite state has an unnamed exit, and named exits (for example, an
unnamed return, and returns named A and B). It is not possible to include
the unnamed return and a subset of the other returns in the <connect list>.
If in the example, the same state is to be taken for the unnamed exit and
exit A (but not exit B), these would have to be shown as two <connect
area>s.
Moreover the Model for <asterisk connect list> is such that in the example
given above, it denotes A and B, but not the unnamed exit.
The abstract grammar for a Connect-node appears to be defined in the wrong
place: it is part of a Composite-state-type-definition, but includes a
Transition which should lead to a Terminator or Decision-node in the context
in which the Composite-state-type-definition is used. In my opinion
Connect-node-set should therefore by part of a State-node, rather than part
of Composite-state-type-definition.
--Suggestions:
1. The keyword DEFAULT should be allowed in the <connect list> meaning the unnamed exit (similar to the DEFAULT entry point).
2. The asterisk notation should also denote the DEFAULT exit.
3. There should be a condition on the abstract grammar that the State-exit-point-name should be defined in the Composite-state-type identified by the Composite-state-type-identifier of the State-node.
4. Change the point in the abstract grammar where Connect-node-set appears to be State-node.
5. Allow <asterisk> to be followed by a list of <\underline{state exit point} name>s (or DEFAULT) meaning all exits except those listed.
-- Rick Reed (at ETSI) Tel: +33 4 92 94 42 68 mob: +44 79 70 50 96 50 email: rickreed#tseng.co.uk
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