Transform base direction from/toRdf. Uses i18n-datatype value for rdfDirection option only.

Author: gkellogg

CHANGELOG.md

@@ -3,6 +3,8 @@
 =======
 ### Added
 - Support for expansion and compaction of values container `"@direction"`.
+- Support for RDF transformation of `@direction`
+  when `rdfDirection` is 'i18n-datatype'.
 
 ## 2.0.2 - 2020-01-17
 

lib/fromRdf.js

@@ -29,6 +29,8 @@ const {
   XSD_STRING,
 } = require('./constants');
 
+const REGEX_BCP47 = /^[a-zA-Z]{1,8}(-[a-zA-Z0-9]{1,8})*$/;
+
 const api = {};
 module.exports = api;
 
@@ -41,7 +43,13 @@ module.exports = api;
  * @return a Promise that resolves to the JSON-LD output.
  */
 api.fromRDF = async (
-  dataset, {useRdfType = false, useNativeTypes = false}) => {
+  dataset,
+  {
+    useRdfType = false,
+    useNativeTypes = false,
+    rdfDirection = null
+  }
+) => {
   const defaultGraph = {};
   const graphMap = {'@default': defaultGraph};
   const referencedOnce = {};
@@ -79,7 +87,7 @@ api.fromRDF = async (
       continue;
     }
 
-    const value = _RDFToObject(o, useNativeTypes);
+    const value = _RDFToObject(o, useNativeTypes, rdfDirection);
     util.addValue(node, p, value, {propertyIsArray: true});
 
     // object may be an RDF list/partial list node but we can't know easily
@@ -270,7 +278,7 @@ api.fromRDF = async (
  *
  * @return the JSON-LD object.
  */
-function _RDFToObject(o, useNativeTypes) {
+function _RDFToObject(o, useNativeTypes, rdfDirection) {
   // convert NamedNode/BlankNode object to JSON-LD
   if(o.termType.endsWith('Node')) {
     return {'@id': o.value};
@@ -320,6 +328,17 @@ function _RDFToObject(o, useNativeTypes) {
       if(![XSD_BOOLEAN, XSD_INTEGER, XSD_DOUBLE, XSD_STRING].includes(type)) {
         rval['@type'] = type;
       }
+    } else if(rdfDirection === 'i18n-datatype' &&
+      type.startsWith('https://www.w3.org/ns/i18n#'))
+    {
+      const [, language, direction] = type.split(/[#_]/);
+      if(language.length > 0) {
+        rval['@language'] = language;
+        if(!language.match(REGEX_BCP47)) {
+          console.warn(`@language must be valid BCP47: ${language}`);
+        }
+      }
+      rval['@direction'] = direction;
     } else if(type !== XSD_STRING) {
       rval['@type'] = type;
     }

lib/toRdf.js

@@ -128,7 +128,8 @@ function _graphToRDF(dataset, graph, graphTerm, issuer, options) {
         }
 
         // convert list, value or node object to triple
-        const object = _objectToRDF(item, issuer, dataset, graphTerm);
+        const object =
+          _objectToRDF(item, issuer, dataset, graphTerm, options.rdfDirection);
         // skip null objects (they are relative IRIs)
         if(object) {
           dataset.push({
@@ -154,7 +155,7 @@ function _graphToRDF(dataset, graph, graphTerm, issuer, options) {
  *
  * @return the head of the list.
  */
-function _listToRDF(list, issuer, dataset, graphTerm) {
+function _listToRDF(list, issuer, dataset, graphTerm, rdfDirection) {
   const first = {termType: 'NamedNode', value: RDF_FIRST};
   const rest = {termType: 'NamedNode', value: RDF_REST};
   const nil = {termType: 'NamedNode', value: RDF_NIL};
@@ -165,7 +166,7 @@ function _listToRDF(list, issuer, dataset, graphTerm) {
   let subject = result;
 
   for(const item of list) {
-    const object = _objectToRDF(item, issuer, dataset, graphTerm);
+    const object = _objectToRDF(item, issuer, dataset, graphTerm, rdfDirection);
     const next = {termType: 'BlankNode', value: issuer.getId()};
     dataset.push({
       subject,
@@ -184,7 +185,7 @@ function _listToRDF(list, issuer, dataset, graphTerm) {
 
   // Tail of list
   if(last) {
-    const object = _objectToRDF(last, issuer, dataset, graphTerm);
+    const object = _objectToRDF(last, issuer, dataset, graphTerm, rdfDirection);
     dataset.push({
       subject,
       predicate: first,
@@ -213,7 +214,7 @@ function _listToRDF(list, issuer, dataset, graphTerm) {
  *
  * @return the RDF literal or RDF resource.
  */
-function _objectToRDF(item, issuer, dataset, graphTerm) {
+function _objectToRDF(item, issuer, dataset, graphTerm, rdfDirection) {
   const object = {};
 
   // convert value object to RDF
@@ -243,6 +244,14 @@ function _objectToRDF(item, issuer, dataset, graphTerm) {
     } else if(types.isNumber(value)) {
       object.value = value.toFixed(0);
       object.datatype.value = datatype || XSD_INTEGER;
+    } else if(rdfDirection === 'i18n-datatype' &&
+      '@direction' in item)
+    {
+      const datatype = 'https://www.w3.org/ns/i18n#' +
+        (item['@language'] || '') +
+        `_${item['@direction']}`;
+      object.datatype.value = datatype;
+      object.value = value;
     } else if('@language' in item) {
       object.value = value;
       object.datatype.value = datatype || RDF_LANGSTRING;
@@ -252,7 +261,8 @@ function _objectToRDF(item, issuer, dataset, graphTerm) {
       object.datatype.value = datatype || XSD_STRING;
     }
   } else if(graphTypes.isList(item)) {
-    const _list = _listToRDF(item['@list'], issuer, dataset, graphTerm);
+    const _list =
+      _listToRDF(item['@list'], issuer, dataset, graphTerm, rdfDirection);
     object.termType = _list.termType;
     object.value = _list.value;
   } else {

tests/test-common.js

@@ -278,9 +278,7 @@ const TEST_TYPES = {
       specVersion: ['json-ld-1.0'],
       // FIXME
       idRegex: [
-        // direction
-        /fromRdf-manifest.jsonld#tdi05$/,
-        /fromRdf-manifest.jsonld#tdi06$/,
+        // direction (compound-literal)
         /fromRdf-manifest.jsonld#tdi11$/,
         /fromRdf-manifest.jsonld#tdi12$/,
       ]
@@ -401,17 +399,7 @@ const TEST_TYPES = {
         /toRdf-manifest.jsonld#tpr36$/,
         /toRdf-manifest.jsonld#tpr37$/,
         /toRdf-manifest.jsonld#tpr39$/,
-        // direction
-        /toRdf-manifest.jsonld#tdi01$/,
-        /toRdf-manifest.jsonld#tdi02$/,
-        /toRdf-manifest.jsonld#tdi03$/,
-        /toRdf-manifest.jsonld#tdi04$/,
-        /toRdf-manifest.jsonld#tdi05$/,
-        /toRdf-manifest.jsonld#tdi06$/,
-        /toRdf-manifest.jsonld#tdi07$/,
-        /toRdf-manifest.jsonld#tdi08$/,
-        /toRdf-manifest.jsonld#tdi09$/,
-        /toRdf-manifest.jsonld#tdi10$/,
+        // direction (compound-literal)
         /toRdf-manifest.jsonld#tdi11$/,
         /toRdf-manifest.jsonld#tdi12$/,
       ]