This repository was originally developed by Eric Prud'hommeaux (@ericprud). All credit goes to him and other original developers. The reason for creating a detached fork (original repo) in the LinkML organization was to be able to support Python 3.14 in LinkML and to put the project in an organization that would allow for sustainability through community exposure as the library did not receive updates in the last years. Efforts to get in touch with the original developers sadly was not successful.

PyShExC - The Python ShExC Parser

This package converts the Shape Expression Compact (ShExC) into Python JSON Schema Binding (pyjsg) objects. The pyjsg object representation can be used to:

• Produce equivalent ShEx definitions in ShEx JSON (ShExJ) notation
• Produce equivalent ShEx definitions in ShEx RDF (ShExR) notation
• Implement a Python ShEx interpreter

History

• 0.4.0 -- Almost ready for 2.1 release. 9 test errors remain, all involving unicode
• 0.4.1 -- Added contextcache. See test_shexr for how to use
• 0.4.2 -- Tweaks in 4 and 8 byte unicode parsing
• 0.5.0 -- Passes all 2.1 tests
• 0.5.1 -- Fix requirements
• 0.5.2 -- Add URL fetch ability and fix UTF8-BOM issue
• 0.5.3 -- Factor out fetch ability for re-use in other packages
• 0.5.4 -- Fix to 0.5.2 -- low probability type matches have to be ignored
• 0.10.0 -- Support for Python 3.10-3.14. Change of build.
• 0.10.1 -- Updated release workflow.

Installation

> pip install PyShExC

Usage

Command Line

usage: shexc_to_shexj [-h] [-nj] [-nr] [-j JSONFILE] [-r RDFFILE]
                      [--context CONTEXT]
                      [-f {trix,trig,ttl,n3,turtle,ntriples,xml,json-ld,nt11,pretty-xml,nquads,nt}]
                      infile

positional arguments:
  infile                Input ShExC specification

optional arguments:
  -h, --help            show this help message and exit
  -nj, --nojson         Do not produce json output
  -nr, --nordf          Do not produce rdf output
  -j JSONFILE, --jsonfile JSONFILE
                        Output ShExJ file (Default: {infile}.json)
  -r RDFFILE, --rdffile RDFFILE
                        Output ShExR file (Default: {infile}.{fmt suffix})
  --context CONTEXT     Alternative @context for json to RDF
  -f {trix,trig,ttl,n3,turtle,ntriples,xml,json-ld,nt11,pretty-xml,nquads,nt}, --format {trix,trig,ttl,n3,turtle,ntriples,xml,json-ld,nt11,pretty-xml,nquads,nt}
                        Output format (Default: turtle)

 > wget https://raw.githubusercontent.com/shexSpec/shexTest/master/schemas/FocusIRI2groupBnodeNested2groupIRIRef.shex -O test.shex
 > shexc_to_shexj test.shex  --context shex.jsonld
  JSON output written to test.json
  turtle output written to test.ttl

test.shex

<http://a.example/S1> IRI /^https?:\/\// {
   <http://a.example/p1> <http://a.example/dt1> ;
   <http://a.example/p2> BNODE {
     <http://a.example/p3> LITERAL ;
     <http://a.example/p4> IRI /^https?:\/\// @<http://a.example/S1>?
   } AND CLOSED { <http://a.example/p3> . ; <http://a.example/p4> . }
}

test.json

{
   "type": "Schema",
   "@context": "http://www.w3.org/ns/shex.jsonld",
   "shapes": [
      {
         "type": "ShapeAnd",
         "id": "http://a.example/S1",
         "shapeExprs": [
            {
               "type": "NodeConstraint",
               "nodeKind": "iri",
               "pattern": "^https?://"
            },
            {
               "type": "Shape",
               "expression": {
                  "type": "EachOf",
                  "expressions": [
                     {
                        "type": "TripleConstraint",
                        "predicate": "http://a.example/p1",
                        "valueExpr": {
                           "type": "NodeConstraint",
                           "datatype": "http://a.example/dt1"

                        }
                     },
                     {
                        "type": "TripleConstraint",
                        "predicate": "http://a.example/p2",
                        "valueExpr": {
                           "type": "ShapeAnd",
                           "shapeExprs": [
                              {
                                 "type": "ShapeAnd",
                                 "shapeExprs": [
                                    {
                                       "type": "NodeConstraint",
                                       "nodeKind": "bnode"
                                    },
                                    {
                                       "type": "Shape",
                                       "expression": {
                                          "type": "EachOf",
                                          "expressions": [
                                             {
                                                "type": "TripleConstraint",
                                                "predicate": "http://a.example/p3",
                                                "valueExpr": {
                                                   "type": "NodeConstraint",
                                                   "nodeKind": "literal"
                                                }
                                             },
                                             {
                                                "type": "TripleConstraint",
                                                "predicate": "http://a.example/p4",
                                                "valueExpr": {
                                                   "type": "ShapeAnd",
                                                   "shapeExprs": [
                                                      {
                                                         "type": "NodeConstraint",
                                                         "nodeKind": "iri",
                                                         "pattern": "^https?://"
                                                      },
                                                      "http://a.example/S1"
                                                   ]
                                                },
                                                "min": 0,
                                                "max": 1
                                             }
                                          ]
                                       }
                                    }
                                 ]
                              },
                              {
                                 "type": "Shape",
                                 "closed": "true",
                                 "expression": {
                                    "type": "EachOf",
                                    "expressions": [
                                       {
                                          "type": "TripleConstraint",
                                          "predicate": "http://a.example/p3"
                                       },
                                       {
                                          "type": "TripleConstraint",
                                          "predicate": "http://a.example/p4"
                                       }
                                    ]
                                 }
                              }
                           ]
                        }
                     }
                  ]
               }
            }
         ]
      }
   ]
}

test.ttl

@prefix rdf: <http://www.w3.org/1999/02/22-rdf-syntax-ns#> .
@prefix rdfs: <http://www.w3.org/2000/01/rdf-schema#> .
@prefix shex: <http://www.w3.org/ns/shex#> .
@prefix xml: <http://www.w3.org/XML/1998/namespace> .
@prefix xsd: <http://www.w3.org/2001/XMLSchema#> .

<http://a.example/S1> a shex:ShapeAnd ;
    shex:shapeExprs ( [ a shex:NodeConstraint ;
                shex:nodeKind shex:iri ;
                shex:pattern "^https?://" ] [ a shex:Shape ;
                shex:expression [ a shex:EachOf ;
                        shex:expressions ( [ a shex:TripleConstraint ;
                                    shex:predicate <http://a.example/p1> ;
                                    shex:valueExpr [ a shex:NodeConstraint ;
                                            shex:datatype <http://a.example/dt1> ] ] [ a shex:TripleConstraint ;
                                    shex:predicate <http://a.example/p2> ;
                                    shex:valueExpr [ a shex:ShapeAnd ;
                                            shex:shapeExprs ( [ a shex:ShapeAnd ;
                                                        shex:shapeExprs ( [ a shex:NodeConstraint ;
                                                                    shex:nodeKind shex:bnode ] [ a shex:Shape ;
                                                                    shex:expression [ a shex:EachOf ;
                                                                            shex:expressions ( [ a shex:TripleConstraint ;

        shex:predicate <http://a.example/p3> ;

        shex:valueExpr [ a shex:NodeConstraint ;

                shex:nodeKind shex:literal ] ] [ a shex:TripleConstraint ;

        shex:max 1 ;

        shex:min 0 ;

        shex:predicate <http://a.example/p4> ;

        shex:valueExpr [ a shex:ShapeAnd ;

                shex:shapeExprs ( [ a shex:NodeConstraint ;

                            shex:nodeKind shex:iri ;

                            shex:pattern "^https?://" ] <http://a.example/S1> ) ] ] ) ] ] ) ] [ a shex:Shape ;
                                                        shex:closed true ;
                                                        shex:expression [ a shex:EachOf ;
                                                                shex:expressions ( [ a shex:TripleConstraint ;
                                                                            shex:predicate <http://a.example/p3> ] [ a shex:TripleConstraint ;
                                                                            shex:predicate <http://a.example/p4> ] ) ] ] ) ] ] ) ] ] ) .

[] a shex:Schema ;
    shex:shapes <http://a.example/S1> .