Set language in HTML

p8 · vinistock · p8 · commit 498311f4471a · 2025-05-05T18:52:24.000+02:00
Setting the language helps with search engines, screen readers and text
rendering. The language defaults to `en` as that is probably most common
(it's also the default for navigation in Darkfish).

Setting the `locale` option will override the language to the locale.

Co-authored-by: Vinicius Stock &lt;vinistock@users.noreply.github.com&gt;
diff --git a/lib/rdoc/generator/darkfish.rb b/lib/rdoc/generator/darkfish.rb
@@ -595,7 +595,7 @@ def assemble_template(body_file)
     <<-TEMPLATE
 <!DOCTYPE html>
 
-<html>
+<html lang="#{@options.locale&.name || 'en'}">
 <head>
 #{head_file.read}
 
diff --git a/test/rdoc/test_rdoc_generator_darkfish.rb b/test/rdoc/test_rdoc_generator_darkfish.rb
@@ -388,6 +388,21 @@ def test_template_stylesheets
     assert_include File.binread('index.html'), %Q[href="./#{base}"]
   end
 
+  def test_html_lang
+    @g.generate
+
+    content = File.binread("index.html")
+    assert_include(content, '<html lang="en">')
+  end
+
+  def test_html_lang_from_locale
+    @options.locale = RDoc::I18n::Locale.new 'ja'
+    @g.generate
+
+    content = File.binread("index.html")
+    assert_include(content, '<html lang="ja">')
+  end
+
   def test_title
     title = "RDoc Test".freeze
     @options.title = title
