Add support for parsing reified triples and triple terms

src/N3Lexer.js

@@ -48,7 +48,7 @@ export default class N3Lexer {
     this._number = /^[\-+]?(?:(\d+\.\d*|\.?\d+)[eE][\-+]?|\d*(\.)?)\d+(?=\.?[,;:\s#()\[\]\{\}"'<>])/;
     this._boolean = /^(?:true|false)(?=[.,;\s#()\[\]\{\}"'<>])/;
     this._keyword = /^@[a-z]+(?=[\s#<:])/i;
-    this._sparqlKeyword = /^(?:PREFIX|BASE|GRAPH)(?=[\s#<])/i;
+    this._sparqlKeyword = /^(?:PREFIX|BASE|VERSION|GRAPH)(?=[\s#<])/i;
     this._shortPredicates = /^a(?=[\s#()\[\]\{\}"'<>])/;
     this._newline = /^[ \t]*(?:#[^\n\r]*)?(?:\r\n|\n|\r)[ \t]*/;
     this._comment = /#([^\n\r]*)/;
@@ -218,7 +218,7 @@ export default class N3Lexer {
 
       case '@':
         // Try to find a language code
-        if (this._previousMarker === 'literal' && (match = this._langcode.exec(input)))
+        if (this._previousMarker === 'literal' && (match = this._langcode.exec(input)) && match[1] !== 'version')
           type = 'langcode', value = match[1];
         // Try to find a keyword
         else if (match = this._keyword.exec(input))
@@ -270,6 +270,8 @@ export default class N3Lexer {
       case 'P':
       case 'G':
       case 'g':
+      case 'V':
+      case 'v':
         // Try to find a SPARQL-style keyword
         if (match = this._sparqlKeyword.exec(input))
           type = match[0].toUpperCase();

src/N3Parser.js

@@ -131,6 +131,11 @@ export default class N3Parser {
       this._sparqlStyle = true;
     case '@base':
       return this._readBaseIRI;
+    // It could be a version declaration
+    case 'VERSION':
+      this._sparqlStyle = true;
+    case '@version':
+      return this._readVersion;
     // It could be a graph
     case '{':
       if (this._supportsNamedGraphs) {
@@ -772,6 +777,16 @@ export default class N3Parser {
     return this._readDeclarationPunctuation;
   }
 
+  // ### `_readVersion` reads version string declaration
+  _readVersion(token) {
+    if (token.type !== 'literal')
+      return this._error('Expected literal to follow version declaration', token);
+    if ((token.end - token.start) !== token.value.length + 2)
+      return this._error('Version declarations must use single quotes', token);
+    this._prefixCallback(token.value);
+    return this._readDeclarationPunctuation;
+  }
+
   // ### `_readNamedGraphLabel` reads the label of a named graph
   _readNamedGraphLabel(token) {
     switch (token.type) {
@@ -1137,18 +1152,20 @@ export default class N3Parser {
   // ## Public methods
 
   // ### `parse` parses the N3 input and emits each parsed quad through the onQuad callback.
-  parse(input, quadCallback, prefixCallback) {
+  parse(input, quadCallback, prefixCallback, versionCallback) {
     // The second parameter accepts an object { onQuad: ..., onPrefix: ..., onComment: ...}
     // As a second and third parameter it still accepts a separate quadCallback and prefixCallback for backward compatibility as well
-    let onQuad, onPrefix, onComment;
-    if (quadCallback && (quadCallback.onQuad || quadCallback.onPrefix || quadCallback.onComment)) {
+    let onQuad, onPrefix, onComment, onVersion;
+    if (quadCallback && (quadCallback.onQuad || quadCallback.onPrefix || quadCallback.onComment || quadCallback.onVersion)) {
       onQuad = quadCallback.onQuad;
       onPrefix = quadCallback.onPrefix;
       onComment = quadCallback.onComment;
+      onVersion = quadCallback.onVersion;
     }
     else {
       onQuad = quadCallback;
       onPrefix = prefixCallback;
+      onVersion = versionCallback;
     }
     // The read callback is the next function to be executed when a token arrives.
     // We start reading in the top context.
@@ -1158,6 +1175,7 @@ export default class N3Parser {
     this._prefixes._ = this._blankNodePrefix ? this._blankNodePrefix.substr(2)
                                              : `b${blankNodePrefix++}_`;
     this._prefixCallback = onPrefix || noop;
+    this._versionCallback = onVersion || noop;
     this._inversePredicate = false;
     this._quantified = Object.create(null);
 

test/N3Lexer-test.js

@@ -711,11 +711,12 @@ describe('Lexer', () => {
 
     it(
       'should tokenize @ keywords',
-      shouldTokenize('@prefix @base @forSome @forAll ',
+      shouldTokenize('@prefix @base @forSome @forAll @version ',
                      { type: '@prefix',  line: 1 },
                      { type: '@base',    line: 1 },
                      { type: '@forSome', line: 1 },
                      { type: '@forAll',  line: 1 },
+                     { type: '@version',  line: 1 },
                      { type: 'eof',      line: 1 }),
     );
 
@@ -755,6 +756,31 @@ describe('Lexer', () => {
                      { type: 'eof', line: 2 }),
     );
 
+    it(
+        'should tokenize @version declarations',
+        shouldTokenize('@version "1.2".\n@version \'1.2-basic\'.',
+            { type: '@version', line: 1 },
+            { type: 'literal', value: '1.2', line: 1 },
+            { type: '.', line: 1 },
+            { type: '@version', line: 2 },
+            { type: 'literal', value: '1.2-basic', line: 2 },
+            { type: '.', line: 2 },
+            { type: 'eof', line: 2 }),
+    );
+
+    it(
+        'should tokenize mixed VERSION @version declarations',
+        shouldTokenize('VERSION "1.2"\nversion "1.2"\n@version "1.2" .',
+            { type: 'VERSION', line: 1 },
+            { type: 'literal', value: '1.2', line: 1 },
+            { type: 'VERSION', line: 2 },
+            { type: 'literal', value: '1.2', line: 2 },
+            { type: '@version', line: 3 },
+            { type: 'literal', value: '1.2', line: 3 },
+            { type: '.', line: 3 },
+            { type: 'eof', line: 3 }),
+    );
+
     it(
       'should tokenize PREFIX declarations',
       shouldTokenize('PREFIX : <http://iri.org/#>\npreFiX abc: <http://iri.org/#>',
@@ -777,6 +803,16 @@ describe('Lexer', () => {
                      { type: 'eof', line: 2 }),
     );
 
+    it(
+        'should tokenize VERSION declarations',
+        shouldTokenize('VERSION "1.2"\nVERSION \'1.2-basic\'',
+            { type: 'VERSION', line: 1 },
+            { type: 'literal', value: '1.2', line: 1 },
+            { type: 'VERSION', line: 2 },
+            { type: 'literal', value: '1.2-basic', line: 2 },
+            { type: 'eof', line: 2 }),
+    );
+
     it(
       'should tokenize blank nodes',
       shouldTokenize('[] [<a> <b>] [a:b "c"^^d:e][a:b[]] _:a:b.',

test/N3Parser-test.js

@@ -838,6 +838,50 @@ describe('Parser', () => {
                   ['http://ex.org/a/bb/ccc/../a', 'http://ex.org/a/bb/ccc/../b', 'http://ex.org/a/bb/ccc/../c']),
     );
 
+    it(
+        'should handle VERSION',
+        shouldParse('VERSION "1.2"'),
+    );
+
+    it(
+        'should handle @version',
+        shouldParse('@version "1.2".'),
+    );
+
+    it(
+        'should handle multiple version declarations',
+        shouldParse('VERSION "1.2"\n' +
+            'version "1.2"\n' +
+            '@version "1.2" .'),
+    );
+
+    it(
+        'should handle multiple version declarations followed by a triple',
+        shouldParse('VERSION "1.2"\n' +
+            'version "1.2"\n' +
+            '@version "1.2" .\n' +
+            '<ex:a> <ex:b> <ex:c> .',
+            ['ex:a', 'ex:b', 'ex:c']),
+    );
+
+    it(
+        'should not allow VERSION with an IRI',
+        shouldNotParse('VERSION <ex:abc>',
+            'Expected literal to follow version declaration on line 1.'),
+    );
+
+    it(
+        'should not allow VERSION with a non-string',
+        shouldNotParse('VERSION 1.2',
+            'Version declarations must use single quotes on line 1.'),
+    );
+
+    it(
+        'should not allow VERSION with a long string',
+        shouldNotParse('VERSION """1.2"""',
+            'Version declarations must use single quotes on line 1.'),
+    );
+
     it('should parse an empty default graph', shouldParse('{}'));
 
     it(