@shexjs/parser

Parse ShExC, return ShExJ

install

npm install --save @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": "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": "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": "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. The ._index provides indexes into the ShExJ's labled shape declarations and triple expressions :

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": [
    {
      "id": "http://a.example/path/S1",
      "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"
          ]
        }
      }
    }
  ],
  "_base": "http://a.example/path/path3",
  "_prefixes": {
    "": "http://a.example/path/path3#"
  },
  "_index": {
    "shapeExprs": {
      "http://a.example/path/S1": <ref to S1 above>
    },
    "tripleExprs": {}
  }
}

Lerna Monorepo

This repo uses lerna to manage multiple NPM packages. These packages are located in packages/*:

• shape-map -- a ShapeMap parser
• @shexjs/parser -- parse ShExC into ShExJ
• @shexjs/writer -- serialize ShExK as ShExC
• @shexjs/term -- RDF terms uses in ShEx
• @shexjs/util -- some utilities for transforming schemas or validation output
• @shexjs/visitor -- a visitor for schemas
• @shexjs/validator -- validate nodes in an RDF graph against shapes in a schema
• @shexjs/eval-validator-api -- API called by @shexjs/validator for validating Shapes, with tripleExpressions and EXTENDS etc.
• @shexjs/eval-simple-1err -- Implementation of @shexjs/eval-validator-api which reports only one error.
• @shexjs/eval-threaded-nerr -- Implementation of @shexjs/eval-validator-api which exhaustively enumerate combinations of ways the data fails to satisfy a shape's expression.
• @shexjs/loader -- an API for loading and using ShEx schemas
• @shexjs/node -- additional API functionality for a node environment
• @shexjs/cli -- a set of command line tools for transformaing and validating with schemas
• @shexjs/webapp -- the shex-simple WEBApp
• @shexjs/shape-path-query -- traverse ShEx schemas with a path language
• @shexjs/extension-test -- a small language for testing semantic actions in ShEx implementations (more)
• @shexjs/extension-map -- an extension for transforming data from one schema to another (more)
• @shexjs/extension-eval -- simple extension which evaluates Javascript semantic action code (more)