ShEx features not supported by DCTAP

The Shape Expressions language (ShEx) is a sophisticated language for describing RDF graph structures, with a well-defined grammar and a level of expressivity beyond what is attainable in a two-dimensional table.

Many ShEx features are not supported in the base DCTAP model, notably:

• Reusable expressions
• Combinations with AND, OR, or NOT
• Nested shapes
• Inverse triple constraints
• Negative triple constraints
• Imported schemas

Other features in the pipeline for the next release of the ShEx semantics include:

• inheritance: defining a shape expression as an extension or restriction of another shape

• abstract shapes: flagging a shape such that only shapes inheriting from that shape may satisfy the shape (analogously to object-oriented programming, where abstract classes may not be instantiated, only used for deriving non-abstract classes)