...
- ordering of slot definitions within an attribute does not adequately address the need to order items in the data.
- defining slots with regular expressions on archetype identifiers is limited, especially if we change the way specialised identifiers work (see here), because of the need to be able to constrain using ontological relationships rather than lexical patterns. Example: not all lab archetypes come under the 'lab_observation' archetype parent.
- currently it is not possible to include a reference to another archetype that has been factored out, the only way to do this is to create a slot whose inclusion pattern matches only one archetype
- the ability to simultaneously match on different parts of an archetype identifier in different ways is limited.
- the semantics of 'redefinition' of slots over specialisation is not defined
- the semantics of the 'include' and 'exclude' parts of the slot statement have not been properly defined.
...
- T1: basic filling: templates specify one or more 'fillers' for a slot (but see notes above).
- T2: complex ordering and occurrences: see bottom of this page herefor an example.
- T3: open/closed: ability to fully specify or leave open an attribute. This means that even if filler archetypes are specified, the author might want to allow those archetypes not to be used at runtime, instead allowing different archetypes that still fit one or more of the available slots in the attribute to be chosen at runtime. In this case, the filler archetypes can be understood as 'recommendations'. On the contrary, if the attribute is defined such that no further fillers could be used, the combined object constraints can be understood as 'required' archetypes.
- T4: ordering: ordering of slot 'fillers' should be independently constrainable from the definition of the slots.
- T5: a template can include another template in a slot rather than an archetype.
...
- Use of structured archetype slot specifications rather than archetype identifier regular expressions.
- Archetype references: the ability to directly refer to another archetype from with an archetype, without using a slot definition;
- Use of specialisation semantics: a slot definition can be specialised into both or either of a narrower slot definition, or one or more archetype references that fit the slot. This allows archetype references can be used as slot-fillers;
- Use of select construct: Use of 'select' construct to support more complex ordering and occurrences requirements (see this page here)
Structured Slot Definition
...
In fact, what we need is a way of separately matching the various parts of an archetype id, and especially for the concept part, some ontological operators. One reason this is needed is that in the future, if the recent governance and identification proposalsare taken up, the concept part of an archetype id will be weakened so that it no longer has to reflect the specialisation relationships of an archetype. The following example shows how such a constraint could look in ADL:
...
One problem that has come up in archteypes and templates to date is the need to specify the ordering of slot fillers. There appear to be two ways to deal with this. The first is to treat the position and related constraints of slots themselves (remembering that there can be more than one within the same attribute) as significant. See the discussion on the lower part of this page for this solution. With the help of the 'select' construct, this approach looks reasonable.
Q: Is there a need for complex ordering, occurrences etc of fillers within a given slot?
A Complex Example
An example of a template expressed as a set of specialised archetypes, based on the above principles is here (HTML files zipped; download and unzip in a local directory; then double click on the COMPOSITION template file). This shows the following features commonly found in templates, but expressed using the ADL 1.5 syntax, including above suggestions:
...