Add insert extension for rendering ++text++ as <ins>text</ins>

README.md

@@ -219,6 +219,7 @@ Commonmarker.to_html('"Hi *there*"', options: {
 | `alerts`                      | Enables the alerts extension.                                                                                       | `false` |
 | `cjk_friendly_emphasis`       | Enables the [CJK friendly emphasis](https://github.com/tats-u/markdown-cjk-friendly) extension.                     | `false` |
 | `highlight`                   | Enables highlighting via `==`                                                                                       | `false` |
+| `insert`                      | Enables the insert extension, rendering `++text++` as `<ins>text</ins>`.                                            | `false` |
 
 For more information on these options, see [the comrak documentation](https://github.com/kivikakk/comrak#usage).
 

ext/commonmarker/src/options.rs

@@ -126,6 +126,7 @@ const EXTENSION_SUBTEXT: &str = "subtext";
 const EXTENSION_ALERTS: &str = "alerts";
 const EXTENSION_CJK_FRIENDLY_EMPHASIS: &str = "cjk_friendly_emphasis";
 const EXTENSION_HIGHLIGHT: &str = "highlight";
+const EXTENSION_INSERT: &str = "insert";
 
 pub fn iterate_extension_options(
     comrak_options: &mut comrak::options::Extension,
@@ -213,6 +214,9 @@ pub fn iterate_extension_options(
                 Cow::Borrowed(EXTENSION_HIGHLIGHT) => {
                     comrak_options.highlight = TryConvert::try_convert(value)?;
                 }
+                Cow::Borrowed(EXTENSION_INSERT) => {
+                    comrak_options.insert = TryConvert::try_convert(value)?;
+                }
                 _ => {}
             }
             Ok(ForEach::Continue)

lib/commonmarker/config.rb

@@ -53,6 +53,7 @@ module Config
         alerts: false,
         cjk_friendly_emphasis: false,
         highlight: false,
+        insert: false,
       }.freeze,
       format: [:html].freeze,
     }.freeze

test/extensions_test.rb

@@ -127,4 +127,18 @@ def test_highlight_extension
       Commonmarker.to_html("This is ==important!==.", options: options),
     )
   end
+
+  def test_insert_extension
+    assert_equal(
+      "<p>This is ++important!++.</p>\n",
+      Commonmarker.to_html("This is ++important!++."),
+    )
+
+    options = { extension: { insert: true } }
+
+    assert_equal(
+      "<p>This is <ins>important!</ins>.</p>\n",
+      Commonmarker.to_html("This is ++important!++.", options: options),
+    )
+  end
 end