ShExJ Schema Graphical Representation (Informative)
Following is a graphical representation of the ShExJ structure. The interconnections in the ShExJ schema are between these structures:
- Schema
- Shape
- ValueExprDefn
- shapeExpr
- valueExpr
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The Shape Expressions (ShEx) language describes RDF graph structures.
A shape describes the triples touching nodes in RDF [[!rdf11-concepts]] graphs.
These descriptions identify predicates and their associated cardinalities and datatypes.
ShEx shapes can be used to communicate data structures associated with some process or interface, generate or validate data, or drive user interfaces.
This document defines the Shape Expressions JASON (ShExJ) format.
Most applications that share data do so using prescribed data structures. While RDFS and OWL enable one to make assertions about the objects in some domain, ShEx describes data structures. This document defines a JSON [[!json]] structure for expressing ShEx schemas.
The ShExJ structure is a sublanguage of JSON. consists of lists and maps of typed objects and values. These are represented as definitions in the following grammar. The content of some constructs involve many choices. These are represented as declarations.
For example, the first production:
Schema : prefixes:[PREFIX->IRI] startActs:[SemAct] start:shapeLabel shapes:[shapeLabel->Shape]
indicates that a Schema object will have these properties:
The grammars below can be viewed with or without human language annotations:
ShExJ schema documents start with the Schema production. The root object will therefor have a "type":"Schema" property.
min and max attributes is the INTEGER 1.| Schema | : | prefixes:[PREFIX->IRI]? valueExprDefns:[valueExprLabel->ValueExprDefn]? startActs:[SemAct]? start:shapeLabel? shapes:[shapeLabel->Shape]? ; |
|---|---|---|
A Schema has a type: "Schema", prefixes: an optional a map from PREFIX to IRI, valueExprDefns: an optional a map from valueExprLabel to ValueExprDefn, startActs: an optional a list of SemActs, start: an optional shapeLabel, and shapes: an optional a map from shapeLabel to Shape. | ||
| { "type":"Schema", "prefixes": { "foaf": "http://xmlns.com/foaf/0.1/", "dc": "http://purl.org/dc/elements/1.1/"}, "valueClasses": { "http://a.example/vs1" ValueClass* }, "startActs": [ SemAct* ], "start":"http://co.example/IssueShape", "shapes":{ "http://co.example/IssueShape": Shape } } | ||
| Shape | : | virtual:BOOL? closed:BOOL? extra:[IRI]? expression:expr? inherit:[shapeLabel]? semActs:[SemAct]? ; |
A Shape has a type: "Shape", virtual: an optional BOOL, closed: an optional BOOL, extra: an optional a list of IRIs, expression: an optional expr, inherit: an optional a list of shapeLabels, and semActs: an optional a list of SemActs. | ||
| { "type":"Shape", "virtual":true, "closed":false, "extra":["http://www.w3.org/2000/01/rdf-Schema#label"], "expression":{ "type":"EachOf", "expressions":[expr], "max":"*" }, "inherit":[] } | ||
| SemAct | : | name:IRI code:STRING ; |
A SemAct has a type: "SemAct", name: IRI, and code: STRING. | ||
| { "type":"SemAct", "name":"http://a.example/extension1", "code":"val dt=o.datatype(); assert(dt.substr(20) == \"http://b.example/dt#\"); " } | ||
| expr | = | EachOf | OneOf | TripleConstraint | Inclusion ; |
| An expr is either: ‣ EachOf ‣ OneOf ‣ TripleConstraint ‣ Inclusion. | ||
| { "type":"TripleConstraint", "valueExpr":{ "type": "ValueClass", "reference": "http://a.example/UserShape" }, "max":"*" }, { "type":"EachOf", "expressions":[expr], "max":"*" } | ||
| EachOf | : | expressions:[expr] min:INTEGER? max:(INTEGER | "*")? semActs:[SemAct]? annotations:[Annotation]? ; |
An EachOf has a type: "EachOf", expressions: a list of exprs, min: an optional INTEGER, max: an optional (INTEGER | "*"), semActs: an optional a list of SemActs, and annotations: an optional a list of Annotations. | ||
| { "type":"EachOf", "expressions":[expr], "max":"*" } | ||
| OneOf | : | expressions:[expr] min:INTEGER? max:(INTEGER | "*")? semActs:[SemAct]? annotations:[Annotation]? ; |
A OneOf has a type: "OneOf", expressions: a list of exprs, min: an optional INTEGER, max: an optional (INTEGER | "*"), semActs: an optional a list of SemActs, and annotations: an optional a list of Annotations. | ||
| { "type":"EachOf", "expressions":[expr], "min":0 } | ||
| Inclusion | : | include:shapeLabel ; |
An Inclusion has a type: "Inclusion", include: shapeLabel. | ||
| { "type":"Inclusion", "include":"http://co.example/IssueShape" } | ||
| TripleConstraint | : | inverse:BOOL? negated:BOOL? predicate:IRI valueExpr:valueExpr min:INTEGER? max:(INTEGER | "*")? semActs:[SemAct]? annotations:[Annotation]? ; |
A TripleConstraint has a type: "TripleConstraint", inverse: an optional BOOL, negated: an optional BOOL, predicate: IRI, valueExpr: valueExpr, min: an optional INTEGER, max: an optional (INTEGER | "*"), semActs: an optional a list of SemActs, and annotations: an optional a list of Annotations. | ||
| { "type":"TripleConstraint", "value":ValueClass, "min":"1", "max":"*", "semActs":[ SemAct ] } | ||
| ValueExprDefn | : | valueExpr:valueExpr semActs:[SemAct]? annotations:[Annotation]? ; |
A ValueExprDefn has a type: "ValueExprDefn", valueExpr: valueExpr, semActs: an optional a list of SemActs, and annotations: an optional a list of Annotations. | ||
| { "type":"ValueExprDefn", "valueExpr": { "type":"ValueClass", "nodeKind":"IRI", "reference":"http://co.example/UserShape" "pattern":"^http://a.example/users/" } } | ||
| valueClassOrRef | = | ValueClass | ValueRef ; |
| A valueClassOrRef is either: ‣ ValueClass ‣ ValueRef. | ||
| { "type":"ValueClass", "reference":"http://co.example/IssueShape" }, { "type": "ValueRef", "valueExprRef": "http://co.example/valueDefn3" } | ||
| valueExpr | = | valueClassOrRef | ValueOr | ValueAnd ; |
| A valueExpr is either: ‣ valueClassOrRef ‣ ValueOr ‣ ValueAnd. | ||
| { "type": "ValueClass", "reference":"http://co.example/IssueShape" }, { "type": "ValueAnd", "valueExprs": [ { "type":"ValueClass", "reference":"http://co.example/IssueShape" }, { "type":"ValueClass", "reference":"http://co.example/RecordShape" } ] } | ||
| ValueClass | : | nodeKind:"literal" xsFacet* |
| | | nodeKind:("iri" | "bnode" | "nonliteral") reference:shapeLabel? stringFacet* | |
| | | datatype:IRI xsFacet* | |
| | | reference:shapeLabel stringFacet* | |
| | | values:[valueSetValue] | |
| | | /* empty */ ; | |
A ValueClass has a type: "ValueClass", either:‣ nodeKind: "literal", and xsFacet*‣ nodeKind: ("iri" | "bnode" | "nonliteral"), reference: an optional shapeLabel, and stringFacet*‣ datatype: IRI, and xsFacet*‣ reference: shapeLabel, and stringFacet*‣ values: a list of valueSetValues‣ no additional properties. | ||
| { "type":"ValueClass", "nodeKind":"IRI", "reference":"http://co.example/UserShape" "pattern":"^http://a.example/users/" } | ||
| ValueRef | : | valueExprRef:shapeLabel ; |
A ValueRef has a type: "ValueRef", valueExprRef: shapeLabel. | ||
| { "type": "ValueRef", "valueExprRef": "http://co.example/valueDefn3" } | ||
| ValueOr | : | valueExprs:[valueClassOrRef] ; |
A ValueOr has a type: "ValueOr", valueExprs: a list of valueClassOrRefs. | ||
| { "type": "ValueAnd", "valueExprs": [ { "type":"ValueClass", "reference":"http://co.example/ResolvedIssueShape" }, { "type":"ValueClass", "reference":"http://co.example/RejectedIssueShape" } ] } | ||
| ValueAnd | : | valueExprs:[valueClassOrRef] ; |
A ValueAnd has a type: "ValueAnd", valueExprs: a list of valueClassOrRefs. | ||
| { "type": "ValueAnd", "valueExprs": [ { "type":"ValueClass", "reference":"http://co.example/IssueShape" }, { "type":"ValueClass", "reference":"http://co.example/RecordShape" } ] } | ||
| Annotation | : | predicate:IRI object:IRI ; |
An Annotation has a type: "Annotation", predicate: IRI, and object: IRI. | ||
| xsFacet | = | stringFacet | numericFacet ; |
| A xsFacet is either: ‣ stringFacet ‣ numericFacet. | ||
| "length":20, "mininclusive":6.02e23 | ||
| stringFacet | = | (length|minlength|maxlength):INTEGER | pattern:STRING ; |
| A stringFacet is either: ‣ one of (length, minlength, maxlength):INTEGER ‣ pattern: STRING. | ||
| "lenght":20, "pattern":"^http://" | ||
| numericFacet | = | (mininclusive|minexclusive|maxinclusive|maxexclusive):numericLiteral |
| | | (totaldigits|fractiondigits):INTEGER ; | |
| A numericFacet is either: ‣ one of (mininclusive, minexclusive, maxinclusive, maxexclusive):numericLiteral ‣ one of (totaldigits, fractiondigits):INTEGER. | ||
| "mininclusive":3.14, "totaldigits":1024 | ||
| valueExprLabel | = | IRI | BNODE ; |
| A valueExprLabel is either: ‣ IRI ‣ BNODE. | ||
| "http://a.example/vs1" | ||
| shapeLabel | = | IRI | BNODE ; |
| A shapeLabel is either: ‣ IRI ‣ BNODE. | ||
| "http://co.example/IssueShape" | ||
| numericLiteral | = | INTEGER | DECIMAL | DOUBLE ; |
| A numericLiteral is either: ‣ INTEGER ‣ DECIMAL ‣ DOUBLE. | ||
| 1, 2.2, 3.3e3 | ||
| valueSetValue | = | IRI |
| | | STRING | |
| | | DATATYPE_STRING | |
| | | LANG_STRING | |
| | | StemRange ; | |
| A valueSetValue is either: ‣ IRI ‣ STRING ‣ DATATYPE_STRING ‣ LANG_STRING ‣ StemRange. | ||
| "http://a.example/assigned", "\"repair\"", { "type":"StemRange", "stem":"http://a.example/" } | ||
| StemRange | : | stem:IRI exclusions:[StemRange] ; |
A StemRange has a type: "StemRange", stem: IRI, and exclusions: a list of StemRanges. | ||
| { "type":"StemRange", "stem":"http://a.example/", "exclusions":[ "http://a.example/a", { "type":"StemRange", "http://a.example/b", } ] } | ||
| Terminals | ||
| PREFIX | = | ^.*$ |
| "foaf", "dc", the emtpy string "" | ||
| IRI | = | ^[^_].*$ |
| "http://co.example/IssueShape", "http://xmlns.com/foaf/0.1/" | ||
| BNODE | = | ^_.*$ |
| "_:IssueShape", "_:b1" | ||
| BOOL | = | ^(true|false)$ |
| true, false | ||
| INTEGER | = | ^.*$ |
| true, false | ||
| DECIMAL | = | ^.*$ |
| 2.2 | ||
| DOUBLE | = | ^.*$ |
| 3.3e3 | ||
| STRING | = | ^.*$ |
| "\"abc\"", "\"Bob said \"The moon is made of green cheese.\"\"" | ||
| DATATYPE_STRING | = | ^.*$ |
| "\"2015-11-15\"<http://www.w3.org/2001/XMLSchema#date>", "\"255\"^^xsd:byte", "\"MCMLXVII\"^^my:romanNumeral" | ||
| LANG_STRING | = | ^.*$ |
| "\"chat\"@fr", "\"Cette Série des Années Septante\"@fr-BE" | ||
Following is a graphical representation of the ShExJ structure. The interconnections in the ShExJ schema are between these structures:
"
The validation results grammar uses some objects from the schema grammar: ShExJ Validation Results documents start with the validation production. The root object will therefor have a "type":"validation" property.
validation : node:IRI, Shape:IRI, solutions:soln A validation object has:type:"validation",node:IRI,Shape:IRI, andsolutions: an array of soln. { "type": "test", "node": "http://a.example/Issue1", "shape": "http://co.example/IssueShape", "solutions": [ soln* ] } soln = groupSolutions | someOfSolutions | tripleConstraintSolutions A soln is either (group, OneOf or TripleConstraint). { "type":"group", "solutions":[soln], "max":"*" } groupSolutions : solutions:[groupSolution] min:INTEGER? max:(INTEGER|"*")? semActs:[SemAct]? A groupSolutions object has:type:"groupSolutions",solutions: an array of groupSolution, (optional)min:INTEGER and (optional)max:((INTEGER|"*"))semActs:[SemAct]?. { "type": "groupSolutions", "solutions": [ groupSolution* ], "min":"1", "max":"*", "semActs":[ SemAct ] } groupSolution : expressions:soln A groupSolution object has:type:"groupSolution",expressions: an array of soln. { "type": "groupSolution", "expressions": [ soln* ], } someOfSolutions : solutions:[someOfSolution] min:INTEGER? max:(INTEGER|"*")? semActs:[SemAct]? A someOfSolutions object has:type:"someOfSolutions",solutions: an array of someOfSolution, (optional)min:INTEGER and (optional)max:((INTEGER|"*"))semActs:[SemAct]?. { "type": "someOfSolutions", "solutions": [ someOfSolution* ], "min":"1", "max":"*", "semActs":[ SemAct ] } someOfSolution : expressions:soln A someOfSolution object has:type:"someOfSolution",expressions: an array of soln. { "type": "someOfSolution", "expressions": [ soln* ], } tripleConstraintSolutions : predicate:IRI value:ValueClass solutions:[testedTriple] min:INTEGER? max:(INTEGER|"*")? semActs:[SemAct]? A tripleConstraintSolutions object has:type:"tripleConstraintSolutions",predicate:IRI,value:ValueClass,solutions: an array of testedTriple, (optional)min:INTEGER and (optional)max:((INTEGER|"*"))semActs:[SemAct]?. { "type": "tripleConstraintSolutions", "solutions": [ tripleConstraintSolution* ], "min":"1", "max":"*", "semActs":[ SemAct ] } testedTriple : subject:(IRI|BNODE), predicate:IRI object:(IRI|STRING|BNODE|dtSTRING|langSTRING) referenced:validation? A testedTriple object has:type:"testedTriple",subject:(IRI or BNODE),predicate:IRI,object:(IRI, STRING, BNODE, dtSTRING or langSTRING), and (optional)referenced:validation. { "type": "test", "subject": "http://inst.example/#Issue1", "predicate": "http://ex.example/#reportedBy", "object": "http://inst.example/#User3", "referenced":{ "type": "test", "node": "http://a.example/User2", "shape": "http://co.example/UserShape", "solutions": [ soln* ] } }
min and max attributes is the INTEGER 1.The Internet Media Type / MIME Type for ShExJ Schemas is "application/json+shexschema".
It is recommended that ShExJ Schemas files have the extension ".shes" (all lowercase) on all platforms.
It is recommended that ShExJ Schemas files stored on Macintosh HFS file systems be given a file type of "TEXT".
This information that follows will be submitted to the IESG for review, approval, and registration with IANA.
charset — this parameter is required when transferring non-ASCII data. If present, the value of charset is always UTF-8.The Internet Media Type / MIME Type for ShExJ Validation Results is "application/json+shexval".
It is recommended that ShExJ Validation Results files have the extension ".shev" (all lowercase) on all platforms.
It is recommended that ShExJ Validation Results files stored on Macintosh HFS file systems be given a file type of "TEXT".
This information that follows will be submitted to the IESG for review, approval, and registration with IANA.
charset — this parameter is required when transferring non-ASCII data. If present, the value of charset is always UTF-8.