@shexjs/writer

Write ShExJ as ShExC

install

npm install --save @shexjs/writer

Quick Start

Invoke from the command line:

node -e 'new (require("@shexjs/writer"))()
  .writeSchema(
    {
      "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"
                }
              ]
            }
          }
        }
      ]
    },
    (error, text, prefixes) => {
      if (error)
        throw error;
      console.log(text);
    })'

The result is a ShExJ expression of the input schema:

<http://a.example/S1> {
  <http://a.example/p1> [1 2]
}

option: base - Base IRI for terse relative URLs

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 'new (require("@shexjs/writer"))({
    base: "http://a.example/"
  })
  .writeSchema(
    {
      "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"
                }
              ]
            }
          }
        }
      ]
    },
    (error, text, prefixes) => {
      if (error)
        throw error;
      console.log(text);
    })'

BASE <http://a.example/>
<S1> {
  <p1> [1 2]
}

option: prefixes - Pre-loaded namespace prefixes

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

node -e 'new (require("@shexjs/writer"))({
    base: "http://a.example/",
    prefixes: {
      "": "http://a.example/path/path3#",
      v: "http://a.example/vocab#"
    }
  })
  .writeSchema(
    {
      "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"
              ]
            }
          }
        }
      ]
    },
    (error, text, prefixes) => {
      if (error)
        throw error;
      console.log(text);
    })'

PREFIX : <http://a.example/path/path3#>
PREFIX v: <http://a.example/vocab#>

BASE <http://a.example/>
<path/S1> {
  :p1 [v:v1 v:v2]
}

option: simplifyParentheses

simplifyParentheses: true eliminates ()s to the degree possible using the ShExC parsing precedunce rules. For example, a ()'d EachOf expression:

<S1> {
(    <p1> . ;
     <p2> @<S2>?)
}

will be serialized without the ()s:

<S1> {
    <p1> . ;
    <p2> @<S2>?
}

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)