DMN12 — No notation for ItemDefinition

The notion of a 'type' or ItemDefinition is in the metamodel (with some pending issues) and in the semantics and concepts, but little is in the notation. Thus, we have notation that allows you to execute an expression with actual arguments, but no notation to allow validation based on type information without actual values.

We have most of the pieces, so it should not be difficult. E.g., individual values can be number, string, date and time, etc. We can allow numeric ranges using our unary tests, e.g. '>0', '[10..30)', etc. We can allow LOVs using "abc", "def", "ghi". These can be 'simple items', and we can also define structures using something similar to boxed contexts.

no proposal for this missing feature, defer

Still seems useful.