The html_lang Jinja2 filter should set the dir HTML attribute (#2220)

betty/jinja2/filter.py

@@ -45,6 +45,7 @@
     UNDETERMINED_LOCALE,
     SPECIAL_LOCALES,
 )
+from betty.locale.error import LocaleError
 from betty.locale.localized import Localized, negotiate_localizeds, LocalizedStr
 from betty.media_type import MediaType
 from betty.media_type.media_types import HTML, SVG
@@ -117,6 +118,12 @@ def filter_localize(
     return localizable.localize(context_localizer(context))
 
 
+_CHARACTER_ORDER_TO_HTML_LANG_MAP = {
+    "left-to-right": "ltr",
+    "right-to-left": "rtl",
+}
+
+
 @pass_context
 def filter_html_lang(
     context: Context,
@@ -130,7 +137,22 @@ def filter_html_lang(
     localizer = context_localizer(context)
     result: str | Markup = localized
     if localized.locale != localizer.locale:
-        result = f'<span lang="{localized.locale}">{localized}</span>'
+        localizer_locale_data = get_data(localizer.locale)
+        localizer_dir = _CHARACTER_ORDER_TO_HTML_LANG_MAP[
+            localizer_locale_data.character_order
+        ]
+        try:
+            localized_locale_data = get_data(localized.locale)
+        except LocaleError:
+            localized_dir = "auto"
+        else:
+            localized_dir = _CHARACTER_ORDER_TO_HTML_LANG_MAP[
+                localized_locale_data.character_order
+            ]
+        dir_attribute = (
+            f' dir="{localized_dir}"' if localized_dir != localizer_dir else ""
+        )
+        result = f'<span lang="{localized.locale}"{dir_attribute}>{localized}</span>'
     if context.eval_ctx.autoescape:
         result = Markup(result)
     return result

betty/tests/jinja2/test_filter.py

@@ -17,7 +17,6 @@
     UNDETERMINED_LOCALE,
     MULTIPLE_LOCALES,
     UNCODED_LOCALE,
-    DEFAULT_LOCALE,
 )
 from betty.locale.localizable import plain
 from betty.locale.localized import Localized, LocalizedStr
@@ -592,16 +591,22 @@ async def test(self) -> None:
 
 class TestFilterHtmlLang(TemplateStringTestBase):
     @pytest.mark.parametrize(
-        ("expected", "autoescape", "localized_locale"),
+        ("expected", "autoescape", "localized_locale", "localizer_locale"),
         [
-            ("Hallo, wereld!", True, DEFAULT_LOCALE),
-            ("Hallo, wereld!", False, DEFAULT_LOCALE),
-            ('<span lang="nl">Hallo, wereld!</span>', True, "nl"),
-            ('<span lang="nl">Hallo, wereld!</span>', False, "nl"),
+            ("Hallo, wereld!", True, "nl", "nl"),
+            ("Hallo, wereld!", False, "nl", "nl"),
+            ('<span lang="nl">Hallo, wereld!</span>', True, "nl", "en"),
+            ('<span lang="nl">Hallo, wereld!</span>', False, "nl", "en"),
+            ('<span lang="nl" dir="ltr">Hallo, wereld!</span>', True, "nl", "ar"),
+            ('<span lang="nl" dir="ltr">Hallo, wereld!</span>', False, "nl", "ar"),
         ],
     )
     async def test(
-        self, expected: str, autoescape: bool, localized_locale: str
+        self,
+        expected: str,
+        autoescape: bool,
+        localized_locale: str,
+        localizer_locale: str,
     ) -> None:
         template = "{{ localized | html_lang }}"
         localized = LocalizedStr("Hallo, wereld!", locale=localized_locale)
@@ -611,6 +616,7 @@ async def test(
                 "localized": localized,
             },
             autoescape=autoescape,
+            locale=localizer_locale,
         ) as (actual, _):
             assert actual == expected
 

betty/tests/project/extension/cotton_candy/assets/templates/entity/test_label_place_html_j2.py

@@ -22,7 +22,7 @@ class Test(TemplateFileTestBase):
         ("expected", "data", "locale"),
         [
             (
-                '<span><a href="/place/P0/index.html"><span lang="und">The Place</span></a></span>',
+                '<span><a href="/place/P0/index.html"><span lang="und" dir="auto">The Place</span></a></span>',
                 {
                     "entity": Place(
                         id="P0",
@@ -54,7 +54,7 @@ class Test(TemplateFileTestBase):
                 "nl",
             ),
             (
-                '<span><span lang="und">The Place</span></span>',
+                '<span><span lang="und" dir="auto">The Place</span></span>',
                 {
                     "entity": Place(
                         id="P0",

betty/tests/project/extension/cotton_candy/assets/templates/entity/test_meta_place_html_j2.py

@@ -38,7 +38,7 @@ async def test_with_enclosing_place_without_place_context(self) -> None:
             names=[Name("The All-enclosing Place")],
         )
         Enclosure(enclosee=enclosing_place, encloser=all_enclosing_place)
-        expected = '<div class="meta">in <span><a href="/place/P1/index.html"><span lang="und">The Enclosing Place</span></a></span>, <span><a href="/place/P2/index.html"><span lang="und">The All-enclosing Place</span></a></span></div>'
+        expected = '<div class="meta">in <span><a href="/place/P1/index.html"><span lang="und" dir="auto">The Enclosing Place</span></a></span>, <span><a href="/place/P2/index.html"><span lang="und" dir="auto">The All-enclosing Place</span></a></span></div>'
         async with self.assert_template_file(
             data={
                 "entity": place,
@@ -61,7 +61,7 @@ async def test_with_enclosing_place_with_matching_place_context(self) -> None:
             names=[Name("The All-enclosing Place")],
         )
         Enclosure(enclosee=enclosing_place, encloser=all_enclosing_place)
-        expected = '<div class="meta">in <span><a href="/place/P1/index.html"><span lang="und">The Enclosing Place</span></a></span></div>'
+        expected = '<div class="meta">in <span><a href="/place/P1/index.html"><span lang="und" dir="auto">The Enclosing Place</span></a></span></div>'
         async with self.assert_template_file(
             data={
                 "entity": place,
@@ -89,7 +89,7 @@ async def test_with_enclosing_place_with_non_matching_place_context(self) -> Non
             id="P999",
             names=[Name("Far Far Away")],
         )
-        expected = '<div class="meta">in <span><a href="/place/P1/index.html"><span lang="und">The Enclosing Place</span></a></span>, <span><a href="/place/P2/index.html"><span lang="und">The All-enclosing Place</span></a></span></div>'
+        expected = '<div class="meta">in <span><a href="/place/P1/index.html"><span lang="und" dir="auto">The Enclosing Place</span></a></span>, <span><a href="/place/P2/index.html"><span lang="und" dir="auto">The All-enclosing Place</span></a></span></div>'
         async with self.assert_template_file(
             data={
                 "entity": place,

betty/tests/project/extension/cotton_candy/assets/templates/test_event_dimensions_html_j2.py

@@ -43,7 +43,7 @@ async def test_with_place(self) -> None:
             id="P0",
             names=[Name("The Place")],
         )
-        expected = 'in <span><a href="/place/P0/index.html"><span lang="und">The Place</span></a></span>'
+        expected = 'in <span><a href="/place/P0/index.html"><span lang="und" dir="auto">The Place</span></a></span>'
         async with self.assert_template_file(
             data={
                 "event": event,
@@ -76,7 +76,7 @@ async def test_with_date_and_place(self) -> None:
             id="P0",
             names=[Name("The Place")],
         )
-        expected = '1970 in <span><a href="/place/P0/index.html"><span lang="und">The Place</span></a></span>'
+        expected = '1970 in <span><a href="/place/P0/index.html"><span lang="und" dir="auto">The Place</span></a></span>'
         async with self.assert_template_file(
             data={
                 "event": event,
@@ -105,7 +105,7 @@ async def test_embedded(self) -> None:
             names=[Name("The Place")],
         )
         event.citations.add(Citation(source=Source(name="The Source")))
-        expected = '1970 in <span><span lang="und">The Place</span></span>'
+        expected = '1970 in <span><span lang="und" dir="auto">The Place</span></span>'
         async with self.assert_template_file(
             data={
                 "event": event,