CurrentDiscussion

Migrated from https://www.w3.org/2001/sw/wiki/ShEx/CurrentDiscussion

Current Discussion and work

=== Discussion 1, redefining and including other SHEX definitions ===

The RELAX NG compact syntax allows for including other definitions and it allows for redefining element in existing definitions. I think it would be nice if SHEX would support something similar.

''Redefining rules''

In the following example a property is been redefined twice ex:Person { ex:age xsd:int, foaf:friend @xsd:Person* } ex:PetLover & ex:Person { foaf:friend @xsd:Pet* } With the current implementation a redefinition means that both rules must be satisfied, which is good.

However, in some cases you would like to either #indicate is that is either should apply to the first or the new rule (what we want in this example) #redefine the rule completely #remove the rule

This would look like ex:Person { ex:age xsd:int, foaf:friend @xsd:Person* } ex:PetLover & ex:Person { |= foaf:friend @xsd:Pet* #define or relation ship with the other rule properties = foaf:friend @xsd:Pet* #completely redefine the rule property

• foaf:friend #remove the rule property }

''Inclusion''

One SHEX file should be able to include another one if defined within a namespace. This could look something like

SHEX ex:persons #define namespace which can then be extended { ex:Person { ex:age xsd:string, foaf:friend @xsd:Person* } }

included by the a second namespace

@include persons1.sh #include file and load all namespaces specified in these file SHEX ex:personsv2 { use ex:persons #use namespace ex:persons ex:Person {(ex:age xsd:string | ex:age xsd:int)?,
= ex:age xsd:int } }

''named groups''

To be able to update/redefine subgroup they should be named. Being able to name them and define separately without them to be directly a Resource Shape would solve the problem of having an higher expressive power in the RDF serialization format than in the SHEX language definition. See RDF_serialization Overview and discussion.

This would look something like #defining an or rule which is not a ResourceShape and can not be referenced by a ShapeProperty, but can be used within an ruleGroup or ResourceShape SHEX ex:persons { @someOrRule { prop1 xsd:string, prop2 xsd:string }

ex:Person & someOrRule { @ageOrGroup(ex:age xsd:string | ex:age xsd:int)?,
} } Which can be the redefined with something like SHEX ex:persons2 { use ex:persons @ageOrGroup { =ex:age xsd:int #redefine the age property to int and remove the optional } }

=== Discussion 2, occurs, multiplicity and reverse multiplicity ===

Currently(28-2-2017) SHEX support the definition of forward as well as reverse multiplicity as it is also possible in UML.

ex:Person { ex:friends @ex:Person* #A person can have multiple friends ^ex:friends @ex:Person* #A person can be friend of multiple persons (reverse multiplicity) ex:spous @ex:Person #Person can only have one lover ^ex:spous @ex:Person #Person can only once Persons spous ex:owns ex:Car* #A Person may own multiple cars }

ex:Car { ex:brand xsd:String ^ex:owns ex:Car* #A car can only have one owner }

However, defining the reverse multiplicity is quiet cumbersome and would look nicer if it would be defined like as

ex:Person { ex:friends @ex:Person*-* #Set forward and reverse multiplicity at once 0:N <-> 0:N ex:spous @ex:Person1-1 #Set forward and reverse multiplicity at once 1:1 <-> 1:1 ex:owns ex:Car*-1 #Set forward and reverse multiplicity at once 1:N <-> 1:N }

ex:Car { ex:brand xsd:String }

=== Discussion 3, enumeration values, full class support ===

In my opinion it would be nice not to only support simple enumeration ranges like:

{ ex:state [ex:unassigned ex:assigned] }

However if would be nice if you could specify a complete ontology like the Gene Ontology or Snomed Ontology. Like

{ ex:function type::GO:Molecular_Function. }

The function property can point to any of the subclasses of the Molecular_Function class in the GO ontology.

Classes/terms/enumeration values within this 'extended' enumeration can define concepts that are subconcepts of other classes/terms/enumeration values.

=== Discussion 4, Support for named graphs===

Proposed for 1.1 See the ShEx/Graph_Named_Graphs page ====Use Cases====

Enable validation outside of a single named graph:

Dataset: Default graph: { :lookInGraph } : { :p2 :o2 }

Schema: { :lookInGraph GRAPH{ @ } } { :p2 . }

=== Discussion 5, Unique ===

• Unique