(registered 2021-05-10, last updated 2021-05-10)

Name: Eric Prud'hommeaux

Email: eric&w3.org

Media type name: text

Media subtype name: shex

Required parameters: None

Optional parameters: None

Encoding considerations: 8bit

   ShEx Compact Syntax (ShExC) is a text language which is encoded in
   UTF-8.

Security considerations: ShExC is purely declarative in nature and 
   contains no active or executable context. However, it does have an
   extension mechanism which can, in principle, evalute arbitrary 
   code, possibly as some trusted agent. Such extensions should not 
   be executed if they don't come from a trusted source.

   Exposing the structure of an RDF graph can reveal information 
   about the content of conformant data. For instance, a schema with 
   a predicate to describe cancer stage indicates that conforming 
   graphs describe patients with cancer. Since ShExC itself does not 
   provide privacy protection, any required protection must be 
   supplied externally, e.g., through the use of SSL/TLS.

   ShExC contains IRIs that must be expanded as part of processing.

   The process of testing a graph's conformance to a schema may 
   involve many detailed queries which could draw resources to 
   respond to API calls or SPARQL queries.

   Given that ShExC allows the substitution of long IRIs with short 
   terms, ShExC documents may expand considerably when processed and,
   in the worst case, the resulting data might consume all of the 
   recipient's resources. Applications should treat any data with due
   skepticism.

Interoperability considerations: N/A

Published specification: http://shex.io/shex-semantics/

Applications which use this media: Any programming environment that 
   requires the exchange of directed graphs. Implementations of ShEx 
   have been created for JavaScript, Python, Ruby, and Java.

Fragment identifier considerations: The structure of a ShEx schema is
   defined by its representation in JSON per ShEx JSON Syntax (ShExJ)
   <http://shex.io/shex-semantics/#shexj>. The JSON-LD context 
   <http://www.w3.org/ns/shex.jsonld> defines the RDF representation 
   (ShExR) for every ShEx schema. A ShEx fragment identifies an 
   instance of either the shapeExpr or tripleExpr ShExJ productions, 
   as well as the RDF resource (see RDF 1.1 Concepts and Abstract 
   Syntax §6 <https://www.w3.org/TR/rdf11-concepts/#section-fragID>) 
   in the corresponding ShExR.

Restrictions on usage: None

Additional information:

   1. Deprecated alias names for this type: None
   2. Magic number(s): None
   3. File extension(s): .shex
   4. Macintosh file type code: TEXT
   5. Object Identifiers: None

General Comments: None

Person to contact for further information:

   1. Name: Eric Prud'hommeaux
   2. Email: eric&w3.org

Intended usage: Common

   See Application Usage

Author/Change controller: W3C