@shexjs/parser

@shexjs/parser

Parse ShExC, return ShExJ

Install

npm install @shexjs/parser

Quick start

Invoke from the command line:

node -e 'console.log(
  JSON.stringify(require("@shexjs/parser")
    .construct()
    .parse("<http://a.example/S1> { <http://a.example/p1> [1 2] }"), null, 2)
)'

The result is a ShExJ expression of the input schema:

{
  "type": "Schema",
  "shapes": [
    {
      "id": "http://a.example/S1",
      "type": "ShapeDecl",
      "shapeExpr": {
        "type": "Shape",
        "expression": {
          "type": "TripleConstraint",
          "predicate": "http://a.example/p1",
          "valueExpr": {
            "type": "NodeConstraint",
            "values": [
              {
                "value": "1",
                "type": "http://www.w3.org/2001/XMLSchema#integer"
              },
              {
                "value": "2",
                "type": "http://www.w3.org/2001/XMLSchema#integer"
              }
            ]
          }
        }
      }
    }
  ]
}

Base IRI

Providing a Base IRI (see MDN docs for URL) allows you to parse schemas with relative URLs for e.g. shape and property names:

node -e 'console.log(
  JSON.stringify(require("@shexjs/parser")
    .construct("http://a.example/")
    .parse("<S1> { <p1> [1 2] }"), null, 2)
)'

{
  "type": "Schema",
  "shapes": [
    {
      "id": "http://a.example/S1",
      "type": "ShapeDecl",
      "shapeExpr": {
        "type": "Shape",
        "expression": {
          "type": "TripleConstraint",
          "predicate": "http://a.example/p1",
          "valueExpr": {
            "type": "NodeConstraint",
            "values": [
              {
                "value": "1",
                "type": "http://www.w3.org/2001/XMLSchema#integer"
              },
              {
                "value": "2",
                "type": "http://www.w3.org/2001/XMLSchema#integer"
              }
            ]
          }
        }
      }
    }
  ]
}

Pre-loaded prefixes

A second parameter to construct is a map for prefixes that are not defined in the schema:

node -e 'console.log(
  JSON.stringify(require("@shexjs/parser")
    .construct("http://a.example/path/path2/", {v: "http://a.example/vocab#"})
    .parse("BASE <../path3>\nPREFIX : <#>\n<S1> { :p1 [v:v1 v:v2] }"), null, 2)
)'

{
  "type": "Schema",
  "shapes": [
    {
      "id": "http://a.example/path/S1",
      "type": "ShapeDecl",
      "shapeExpr": {
        "type": "Shape",
        "expression": {
          "type": "TripleConstraint",
          "predicate": "http://a.example/path/path3#p1",
          "valueExpr": {
            "type": "NodeConstraint",
            "values": [
              "http://a.example/vocab#v1",
              "http://a.example/vocab#v2"
            ]
          }
        }
      }
    }
  ]
}

Index option

The third construct parameter is for passing parsing options. One handy one is index, which returns the final base (._base) and prefix mapping (._prefixes) encountered during parsing, indexes the labeled shape declarations and triple expressions (._index), and records where each declaration was parsed (._locations) — what editor tooling wants:

node -e 'console.log(
  JSON.stringify(require("@shexjs/parser")
    .construct("http://a.example/path/path2/", {v: "http://a.example/vocab#"}, {index:true})
    .parse("BASE <../path3>\nPREFIX : <#>\n<S1> { :p1 [v:v1 v:v2] }"), null, 2)
)'

{
  "type": "Schema",
  "shapes": [ … as above … ],
  "_base": "http://a.example/path/path3",
  "_prefixes": {
    "": "http://a.example/path/path3#"
  },
  "_index": {
    "shapeExprs": {
      "http://a.example/path/S1": { … the ShapeDecl above … }
    },
    "tripleExprs": {}
  },
  "_sourceMap": null,
  "_locations": {
    "http://a.example/path/S1": {
      "filename": "http://a.example/path/path2/",
      "first_line": 3,
      "first_column": 0,
      "last_line": 3,
      "last_column": 24
    }
  },
  "_exprLocations": {}
}

@shexjs/parser is one of the shex.js packages; installing shex pulls in the whole suite, and its README maps them.