Improve @direction support.

- Support `compound-literal` `rdfDirection` option.
- Emit `toRdf` warning if `@direction` is used and `rdfDirection` is not
  set.
- Add safe mode support for `@direction`. Using `@direction` without
  `rdfDirection` set will cause a safe mode failure.
- Add tests.

CHANGELOG.md

@@ -1,5 +1,15 @@
 # jsonld ChangeLog
 
+## 8.3.0 - 2023-09-xx
+
+### Added
+- Support `compound-literal` `rdfDirection` option.
+- Emit `toRdf` warning if `@direction` is used and `rdfDirection` is not set.
+
+### Fixed
+- Add safe mode support for `@direction`. Using `@direction` without
+  `rdfDirection` set will cause a safe mode failure.
+
 ## 8.2.1 - 2023-08-31
 
 ### Fixed

lib/events.js

@@ -123,7 +123,9 @@ const _notSafeEventCodes = new Set([
   'relative graph reference',
   'relative object reference',
   'relative predicate reference',
-  'relative subject reference'
+  'relative subject reference',
+  // toRDF / fromRDF
+  'rdfDirection not set'
 ]);
 
 // safe handler that rejects unsafe warning conditions

lib/fromRdf.js

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2017 Digital Bazaar, Inc. All rights reserved.
+ * Copyright (c) 2017-2023 Digital Bazaar, Inc. All rights reserved.
  */
 'use strict';
 
@@ -18,7 +18,7 @@ const {
 
 // constants
 const {
-  // RDF,
+  RDF,
   RDF_LIST,
   RDF_FIRST,
   RDF_REST,
@@ -52,14 +52,30 @@ api.fromRDF = async (
   dataset,
   options
 ) => {
-  const defaultGraph = {};
-  const graphMap = {'@default': defaultGraph};
-  const referencedOnce = {};
   const {
     useRdfType = false,
     useNativeTypes = false,
     rdfDirection = null
   } = options;
+  // FIXME: use Maps?
+  const defaultGraph = {};
+  const graphMap = {'@default': defaultGraph};
+  const referencedOnce = {};
+  let processCompoundLiterals = false;
+  if(rdfDirection) {
+    if(rdfDirection === 'compound-literal') {
+      processCompoundLiterals = true;
+    } else if(rdfDirection !== 'i18n-datatype') {
+      throw new JsonLdError(
+        'Unknown rdfDirection value.',
+        'jsonld.InvalidRdfDirection',
+        {value: rdfDirection});
+    }
+  }
+  let compoundLiteralSubjects;
+  if(processCompoundLiterals) {
+    compoundLiteralSubjects = {};
+  }
 
   for(const quad of dataset) {
     // TODO: change 'name' to 'graph'
@@ -68,11 +84,18 @@ api.fromRDF = async (
     if(!(name in graphMap)) {
       graphMap[name] = {};
     }
+    if(processCompoundLiterals && !(name in compoundLiteralSubjects)) {
+      compoundLiteralSubjects[name] = {};
+    }
     if(name !== '@default' && !(name in defaultGraph)) {
       defaultGraph[name] = {'@id': name};
     }
 
     const nodeMap = graphMap[name];
+    let compoundMap;
+    if(processCompoundLiterals) {
+      compoundMap = compoundLiteralSubjects[name];
+    }
 
     // get subject, predicate, object
     const s = quad.subject.value;
@@ -83,6 +106,9 @@ api.fromRDF = async (
       nodeMap[s] = {'@id': s};
     }
     const node = nodeMap[s];
+    if(processCompoundLiterals && p === RDF + 'direction') {
+      compoundMap[s] = true;
+    }
 
     const objectIsNode = o.termType.endsWith('Node');
     if(objectIsNode && !(o.value in nodeMap)) {
@@ -194,6 +220,64 @@ api.fromRDF = async (
   for(const name in graphMap) {
     const graphObject = graphMap[name];
 
+    if(processCompoundLiterals) {
+      if(name in compoundLiteralSubjects) {
+        const cls = compoundLiteralSubjects[name];
+        for(const cl of Object.keys(cls)) {
+          const clEntry = referencedOnce[cl];
+          if(!clEntry) {
+            continue;
+          }
+          const node = clEntry.node;
+          const property = clEntry.property;
+          //const value = clEntry.value;
+          const clNode = graphObject[cl];
+          if(!types.isObject(clNode)) {
+            continue;
+          }
+          delete graphObject[cl];
+          for(const clReference of node[property]) {
+            if(clReference['@id'] === cl) {
+              delete clReference['@id'];
+            }
+            const value = clNode[RDF + 'value'];
+            // FIXME: error on !== 1 value
+            clReference['@value'] = value[0]['@value'];
+            const language = clNode[RDF + 'language'];
+            if(language) {
+              // FIXME: error on !== 1 language value
+              const v = language[0]['@value'];
+              if(!v.match(REGEX_BCP47)) {
+                throw new JsonLdError(
+                  'Invalid RDF syntax; rdf:language must be valid BCP47.',
+                  'jsonld.SyntaxError',
+                  {
+                    code: 'invalid language-tagged string',
+                    value: v
+                  });
+              }
+              clReference['@language'] = v;
+            }
+            const direction = clNode[RDF + 'direction'];
+            if(direction) {
+              // FIXME: error on !== 1 direction value
+              const v = direction[0]['@value'];
+              if(!(v === 'ltr' || v === 'rtl')) {
+                throw new JsonLdError(
+                  'Invalid RDF syntax; rdf:direction must be "ltr" or "rtl".',
+                  'jsonld.SyntaxError',
+                  {
+                    code: 'invalid base direction',
+                    value: v
+                  });
+              }
+              clReference['@direction'] = v;
+            }
+          }
+        }
+      }
+    }
+
     // no @lists to be converted, continue
     if(!(RDF_NIL in graphObject)) {
       continue;
@@ -282,7 +366,8 @@ api.fromRDF = async (
  *
  * @param o the RDF triple object to convert.
  * @param useNativeTypes true to output native types, false not to.
- * @param rdfDirection text direction mode [null, i18n-datatype]
+ * @param rdfDirection text direction mode [null, i18n-datatype,
+ *   compound-literal]
  * @param options top level API options
  *
  * @return the JSON-LD object.

lib/jsonld.js

@@ -118,7 +118,8 @@ const _resolvedContextCache = new LRU({max: RESOLVED_CONTEXT_CACHE_MAX_SIZE});
  *          [graph] true to always output a top-level graph (default: false).
  *          [expandContext] a context to expand with.
  *          [skipExpansion] true to assume the input is expanded and skip
- *            expansion, false not to, defaults to false.
+ *            expansion, false not to, defaults to false. Some well-formed
+ *            and safe-mode checks may be omitted.
  *          [documentLoader(url, options)] the document loader.
  *          [framing] true if compaction is occuring during a framing operation.
  *          [safe] true to use safe mode. (default: false)
@@ -538,13 +539,16 @@ jsonld.link = async function(input, ctx, options) {
  *          [base] the base IRI to use (default: `null`).
  *          [expandContext] a context to expand with.
  *          [skipExpansion] true to assume the input is expanded and skip
- *            expansion, false not to, defaults to false.
+ *            expansion, false not to, defaults to false. Some well-formed
+ *            and safe-mode checks may be omitted.
  *          [inputFormat] the format if input is not JSON-LD:
  *            'application/n-quads' for N-Quads.
  *          [format] the format if output is a string:
  *            'application/n-quads' for N-Quads.
  *          [documentLoader(url, options)] the document loader.
  *          [useNative] true to use a native canonize algorithm
+ *          [rdfDirection] 'i18n-datatype' or 'compound-literal' to support RDF
+ *             transformation of @direction (default: null).
  *          [safe] true to use safe mode. (default: true).
  *          [contextResolver] internal use only.
  *
@@ -601,8 +605,8 @@ jsonld.normalize = jsonld.canonize = async function(input, options) {
  *            (default: false).
  *          [useNativeTypes] true to convert XSD types into native types
  *            (boolean, integer, double), false not to (default: false).
- *          [rdfDirection] 'i18n-datatype' to support RDF transformation of
- *             @direction (default: null).
+ *          [rdfDirection] 'i18n-datatype' or 'compound-literal' to support RDF
+ *             transformation of @direction (default: null).
  *          [safe] true to use safe mode. (default: false)
  *
  * @return a Promise that resolves to the JSON-LD document.
@@ -647,13 +651,16 @@ jsonld.fromRDF = async function(dataset, options) {
  *          [base] the base IRI to use.
  *          [expandContext] a context to expand with.
  *          [skipExpansion] true to assume the input is expanded and skip
- *            expansion, false not to, defaults to false.
+ *            expansion, false not to, defaults to false. Some well-formed
+ *            and safe-mode checks may be omitted.
  *          [format] the format to use to output a string:
  *            'application/n-quads' for N-Quads.
  *          [produceGeneralizedRdf] true to output generalized RDF, false
  *            to produce only standard RDF (default: false).
  *          [documentLoader(url, options)] the document loader.
  *          [safe] true to use safe mode. (default: false)
+ *          [rdfDirection] 'i18n-datatype' or 'compound-literal' to support RDF
+ *             transformation of @direction (default: null).
  *          [contextResolver] internal use only.
  *
  * @return a Promise that resolves to the RDF dataset.

lib/toRdf.js

@@ -1,12 +1,13 @@
 /*
- * Copyright (c) 2017 Digital Bazaar, Inc. All rights reserved.
+ * Copyright (c) 2017-2023 Digital Bazaar, Inc. All rights reserved.
  */
 'use strict';
 
 const {createNodeMap} = require('./nodeMap');
 const {isKeyword} = require('./context');
 const graphTypes = require('./graphTypes');
 const jsonCanonicalize = require('canonicalize');
+const JsonLdError = require('./JsonLdError');
 const types = require('./types');
 const util = require('./util');
 
@@ -15,7 +16,7 @@ const {
 } = require('./events');
 
 const {
-  // RDF,
+  RDF,
   // RDF_LIST,
   RDF_FIRST,
   RDF_REST,
@@ -312,18 +313,125 @@ function _objectToRDF(
     } 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'] || '') +
-        `_${item['@direction']}`;
+    } else if('@direction' in item && rdfDirection === 'i18n-datatype') {
+      const language = (item['@language'] || '').toLowerCase();
+      const direction = item['@direction'];
+      const datatype = `https://www.w3.org/ns/i18n#${language}_${direction}`;
       object.datatype.value = datatype;
       object.value = value;
+    } else if('@direction' in item && rdfDirection === 'compound-literal') {
+      const language = (item['@language'] || '').toLowerCase();
+      const direction = item['@direction'];
+      // blank node
+      object.termType = 'BlankNode';
+      object.value = issuer.getId();
+      object.datatype = undefined;
+      // value
+      dataset.push({
+        subject: {
+          termType: object.termType,
+          value: object.value
+        },
+        predicate: {
+          termType: 'NamedNode',
+          value: RDF + 'value'
+        },
+        object: {
+          termType: 'Literal',
+          value,
+          datatype: {
+            termType: 'NamedNode',
+            value: XSD_STRING
+          }
+        },
+        graph: graphTerm
+      });
+      // language if preset
+      if(language !== '') {
+        dataset.push({
+          subject: {
+            termType: object.termType,
+            value: object.value
+          },
+          predicate: {
+            termType: 'NamedNode',
+            value: RDF + 'language'
+          },
+          object: {
+            termType: 'Literal',
+            value: language,
+            datatype: {
+              termType: 'NamedNode',
+              value: XSD_STRING
+            }
+          },
+          graph: graphTerm
+        });
+      }
+      // direction
+      dataset.push({
+        subject: {
+          termType: object.termType,
+          value: object.value
+        },
+        predicate: {
+          termType: 'NamedNode',
+          value: RDF + 'direction'
+        },
+        object: {
+          termType: 'Literal',
+          value: direction,
+          datatype: {
+            termType: 'NamedNode',
+            value: XSD_STRING
+          }
+        },
+        graph: graphTerm
+      });
+    } else if('@direction' in item && rdfDirection) {
+      throw new JsonLdError(
+        'Unknown rdfDirection value.',
+        'jsonld.InvalidRdfDirection',
+        {value: rdfDirection});
     } else if('@language' in item) {
+      if('@direction' in item && rdfDirection === null) {
+        if(options.eventHandler) {
+          // FIXME: only emit once?
+          _handleEvent({
+            event: {
+              type: ['JsonLdEvent'],
+              code: 'rdfDirection not set',
+              level: 'warning',
+              message: 'rdfDirection not set for @direction.',
+              details: {
+                object: object.value
+              }
+            },
+            options
+          });
+        }
+      }
       object.value = value;
       object.datatype.value = datatype || RDF_LANGSTRING;
       object.language = item['@language'];
     } else {
+      if('@direction' in item && rdfDirection === null) {
+        if(options.eventHandler) {
+          // FIXME: only emit once?
+          _handleEvent({
+            event: {
+              type: ['JsonLdEvent'],
+              code: 'rdfDirection not set',
+              level: 'warning',
+              message: 'rdfDirection not set for @direction.',
+              details: {
+                object: object.value
+              }
+            },
+            options
+          });
+        }
+      }
       object.value = value;
       object.datatype.value = datatype || XSD_STRING;
     }