Update description of i18n datatype and Compound Literal to lower case language tags.

For w3c/json-ld-api#337.

Author: gkellogg

Gemfile.lock

@@ -1,11 +1,11 @@
 GIT
   remote: git://github.com/ruby-rdf/json-ld.git
-  revision: d0bfdefb6cddac6a22683ff9733a94936c4e5dbe
+  revision: 241ef57e096cefdff55ef6d39a917049eec04529
   branch: develop
   specs:
     json-ld (3.1.0)
       htmlentities (~> 4.3)
-      json-canonicalization (~> 0.1)
+      json-canonicalization (~> 0.2)
       link_header (~> 0.0, >= 0.0.8)
       multi_json (~> 1.14)
       rack (~> 2.0)
@@ -19,7 +19,7 @@ GEM
     bcp47 (0.3.3)
       i18n
     builder (3.2.4)
-    byebug (11.0.1)
+    byebug (11.1.1)
     colorize (0.8.1)
     concurrent-ruby (1.1.5)
     connection_pool (2.2.2)
@@ -34,9 +34,9 @@ GEM
     hamster (3.0.0)
       concurrent-ruby (~> 1.0)
     htmlentities (4.3.4)
-    i18n (1.7.0)
+    i18n (1.8.2)
       concurrent-ruby (~> 1.0)
-    json-canonicalization (0.1.0)
+    json-canonicalization (0.2.0)
     json-ld-preloaded (3.1.0)
       json-ld (~> 3.1)
       rdf (~> 3.1)
@@ -80,10 +80,10 @@ GEM
       mini_portile2 (~> 2.4.0)
     nokogumbo (2.0.2)
       nokogiri (~> 1.8, >= 1.8.4)
-    public_suffix (4.0.1)
-    rack (2.0.8)
+    public_suffix (4.0.3)
+    rack (2.1.2)
     rake (13.0.1)
-    rdf (3.1.0)
+    rdf (3.1.1)
       hamster (~> 3.0)
       link_header (~> 0.0, >= 0.0.8)
     rdf-aggregate-repo (3.1.0)
@@ -134,7 +134,7 @@ GEM
     rdf-turtle (3.1.0)
       ebnf (~> 1.2)
       rdf (~> 3.1)
-    rdf-vocab (3.1.0)
+    rdf-vocab (3.1.1)
       rdf (~> 3.1)
     rdf-xsd (3.1.0)
       rdf (~> 3.1)

index.html

@@ -12913,11 +12913,14 @@ <h3>Serializing/Deserializing RDF</h3>
     <p>The <a data-cite="JSON-LD11-API#deserialize-json-ld-to-rdf-algorithm">Deserialize JSON-LD to RDF Algorithm</a>
       can be used with the <dfn data-cite="JSON-LD11-API#dom-jsonldoptions-rdfdirection">rdfDirection</dfn> option
       set to `i18n-datatype` to generate <a>RDF literals</a> using the `i18n` base to create an IRI
-      encoding the <a>base direction</a> along with optional <a>language tag</a> from
-      value objects containing `@direction` by appending to `https://www.w3.org/ns/i18n#`
+      encoding the <a>base direction</a> along with optional <a>language tag</a> (normalized to lower case)
+      from value objects containing `@direction` by appending to `https://www.w3.org/ns/i18n#`
       the value of `@language`, if any, followed by an underscore (`"_"`) followed
       by the value of `@direction`.</p>
 
+    <p>For improved interoperability, the <a>language tag</a> is normalized to
+      lower case when creating the datatype IRI.</p>
+
     <p class="issue atrisk">This feature is experimental, as RDF does not have a
       standard way to represent base direction in <a>RDF literals</a>.
       A future RDF Working Group may support base direction differently.
@@ -12937,8 +12940,8 @@ <h3>Serializing/Deserializing RDF</h3>
 
     # Note that this version preserves the base direction using a non-standard datatype.
     [
-      ex:title ****"HTML و CSS: تصميم و إنشاء مواقع الويب"^^i18n:ar-EG_rtl****;
-      ex:publisher ****"مكتبة"^^i18n:ar-EG_rtl****
+      ex:title ****"HTML و CSS: تصميم و إنشاء مواقع الويب"^^i18n:ar-eg_rtl****;
+      ex:publisher ****"مكتبة"^^i18n:ar-eg_rtl****
     ] .
     -->
     </pre>
@@ -12968,8 +12971,11 @@ <h3>Serializing/Deserializing RDF</h3>
     <p>The <a data-cite="JSON-LD11-API#deserialize-json-ld-to-rdf-algorithm">Deserialize JSON-LD to RDF Algorithm</a>
       can be used with the <a>rdfDirection</a> option
       set to `compound-literal` to generate <a>RDF literals</a> using these properties to
-      describe the <a>base direction</a> and optional <a>language tag</a> from
-      value objects containing `@direction` and optionally `@language`.</p>
+      describe the <a>base direction</a> and optional <a>language tag</a> (normalized to lower case)
+      from value objects containing `@direction` and optionally `@language`.</p>
+
+    <p>For improved interoperability, the <a>language tag</a> is normalized to
+      lower case when creating the datatype IRI.</p>
 
     <p class="issue atrisk">This feature is experimental, as RDF does not have a
       standard way to represent base direction in <a>RDF literals</a>.
@@ -12991,12 +12997,12 @@ <h3>Serializing/Deserializing RDF</h3>
     [
       ex:title ****[
         rdf:value "HTML و CSS: تصميم و إنشاء مواقع الويب",
-        rdf:language "ar-EG",
+        rdf:language "ar-eg",
         rdf:direction "rtl"
       ]****;
       ex:publisher ****[
         rdf:value "مكتبة",
-        rdf:language "ar-EG",
+        rdf:language "ar-eg",
         rdf:direction "rtl"
       ]****
     ] .
@@ -13701,6 +13707,8 @@ <h2>Changes since JSON-LD Community Group Final Report</h2>
     <li>Allow further structured subtypes of `application/ld+json` by using
       `+ld+json` as a suffix for a new base type.</li>
     <li>Warn about forward-compatibility issues for terms of the form (`"@"1*ALPHA`).</li>
+    <li>When creating an `i18n` datatype or `rdf:CompoundLiteral`, <a>language tags</a> are
+      normalized to lower case to improve interoperability between implementations.</li>
   </ul>
 </section>
 <section class="appendix informative" id="changes-from-cr">