Add support for alerts extension

Author: gjtorikian

README.md

@@ -209,6 +209,8 @@ Commonmarker.to_html('"Hi *there*"', options: {
 | `underline`                   | Enables the underline extension.                                                                                    | `false` |
 | `spoiler`                     | Enables the spoiler extension.                                                                                      | `false` |
 | `greentext`                   | Enables the greentext extension.                                                                                    | `false` |
+| `subscript`                   | Enables the subscript extension.                                                                                    | `false` |
+| `alerts`                      | Enables the alerts extension.                                                                                       | `false` |
 
 For more information on these options, see [the comrak documentation](https://github.com/kivikakk/comrak#usage).
 

ext/commonmarker/src/node.rs

@@ -1,9 +1,9 @@
 use comrak::arena_tree::Node as ComrakNode;
 use comrak::nodes::{
-    Ast as ComrakAst, AstNode as ComrakAstNode, ListDelimType, ListType, NodeCode, NodeCodeBlock,
-    NodeDescriptionItem, NodeFootnoteDefinition, NodeFootnoteReference, NodeHeading, NodeHtmlBlock,
-    NodeLink, NodeList, NodeMath, NodeMultilineBlockQuote, NodeShortCode, NodeTable,
-    NodeValue as ComrakNodeValue, NodeWikiLink, TableAlignment,
+    AlertType, Ast as ComrakAst, AstNode as ComrakAstNode, ListDelimType, ListType, NodeAlert,
+    NodeCode, NodeCodeBlock, NodeDescriptionItem, NodeFootnoteDefinition, NodeFootnoteReference,
+    NodeHeading, NodeHtmlBlock, NodeLink, NodeList, NodeMath, NodeMultilineBlockQuote,
+    NodeShortCode, NodeTable, NodeValue as ComrakNodeValue, NodeWikiLink, TableAlignment,
 };
 use magnus::RArray;
 use magnus::{function, method, scan_args, Module, Object, RHash, RModule, Symbol, Value};
@@ -473,6 +473,47 @@ impl CommonmarkerNode {
                 ComrakNodeValue::WikiLink(NodeWikiLink { url })
             }
 
+            "alert" => {
+                let kwargs = scan_args::get_kwargs::<
+                    _,
+                    (Symbol,),
+                    (Option<String>, Option<bool>, Option<usize>, Option<usize>),
+                    (),
+                >(
+                    args.keywords,
+                    &["type"],
+                    &["title", "multiline", "fence_length", "fence_offset"],
+                )?;
+
+                let (alert_name,) = kwargs.required;
+                let (title, multiline, fence_length, fence_offset) = kwargs.optional;
+
+                let alert_type = match alert_name.to_string().as_str() {
+                    "note" => AlertType::Note,
+                    "tip" => AlertType::Tip,
+                    "important" => AlertType::Important,
+                    "warning" => AlertType::Warning,
+                    _ => {
+                        return Err(magnus::Error::new(
+                            magnus::exception::arg_error(),
+                            "alert type must be `note`, `tip`, `important`, or `warning`",
+                        ));
+                    }
+                };
+
+                ComrakNodeValue::Alert(NodeAlert {
+                    alert_type,
+                    // Overridden title. If None, then use the default title.
+                    title,
+                    // Originated from a multiline blockquote.
+                    multiline: multiline.unwrap_or(false),
+                    // The length of the fence (multiline only).
+                    fence_length: fence_length.unwrap_or(0),
+                    // The indentation level of the fence marker (multiline only)
+                    fence_offset: fence_offset.unwrap_or(0),
+                })
+            }
+
             _ => panic!("unknown node type {}", node_type),
         };
 
@@ -565,6 +606,7 @@ impl CommonmarkerNode {
             ComrakNodeValue::Subscript => Symbol::new("subscript"),
             ComrakNodeValue::SpoileredText => Symbol::new("spoilered_text"),
             ComrakNodeValue::EscapedTag(_) => Symbol::new("escaped_tag"),
+            ComrakNodeValue::Alert(..) => Symbol::new("alert"),
         }
     }
 

ext/commonmarker/src/options.rs

@@ -117,6 +117,7 @@ const EXTENSION_UNDERLINE: &str = "underline";
 const EXTENSION_SPOILER: &str = "spoiler";
 const EXTENSION_GREENTEXT: &str = "greentext";
 const EXTENSION_SUBSCRIPT: &str = "subscript";
+const EXTENSION_ALERTS: &str = "alerts";
 
 fn iterate_extension_options(comrak_options: &mut ComrakOptions, options_hash: RHash) {
     options_hash
@@ -189,6 +190,9 @@ fn iterate_extension_options(comrak_options: &mut ComrakOptions, options_hash: R
                 Ok(Cow::Borrowed(EXTENSION_SUBSCRIPT)) => {
                     comrak_options.extension.subscript = TryConvert::try_convert(value)?;
                 }
+                Ok(Cow::Borrowed(EXTENSION_ALERTS)) => {
+                    comrak_options.extension.alerts = TryConvert::try_convert(value)?;
+                }
                 _ => {}
             }
             Ok(ForEach::Continue)

lib/commonmarker/config.rb

@@ -46,6 +46,7 @@ module Config
         spoiler: false,
         greentext: false,
         subscript: false,
+        alerts: false,
       }.freeze,
       format: [:html].freeze,
     }.freeze

test/alert_test.rb

@@ -0,0 +1,64 @@
+# frozen_string_literal: true
+
+require "test_helper"
+
+class FrontmatterTest < Minitest::Test
+  def test_renders_alert_notes
+    md = "> [!note]\n> Something of note"
+
+    expected = <<~HTML
+      <blockquote>
+      <p>[!note]<br />
+      Something of note</p>
+      </blockquote>
+    HTML
+
+    # without extension
+    assert_equal(expected, Commonmarker.to_html(md))
+
+    expected = <<~HTML
+      <div class="alert alert-note">
+      <p class="alert-title">Note</p>
+      <p>Something of note</p>
+      </div>
+    HTML
+
+    assert_equal(expected, Commonmarker.to_html(md, options: { extension: { alerts: true } }))
+  end
+
+  def test_renders_alert_tip
+    md = "> [!TIP]\n> Something of tip"
+
+    expected = <<~HTML
+      <blockquote>
+      <p>[!TIP]<br />
+      Something of tip</p>
+      </blockquote>
+    HTML
+
+    # without extension
+    assert_equal(expected, Commonmarker.to_html(md))
+
+    expected = <<~HTML
+      <div class="alert alert-tip">
+      <p class="alert-title">Tip</p>
+      <p>Something of tip</p>
+      </div>
+    HTML
+
+    assert_equal(expected, Commonmarker.to_html(md, options: { extension: { alerts: true } }))
+  end
+
+  def test_renders_a_complicated_node
+    node = Commonmarker::Node.new(:alert, type: :warning, title: "This is bad")
+
+    assert_equal(:alert, node.type)
+
+    expected = <<~HTML
+      <div class="alert alert-warning">
+      <p class="alert-title">This is bad</p>
+      </div>
+    HTML
+    assert_equal(expected, node.to_html)
+  end
+end

test/node/creation_test.rb

@@ -45,6 +45,7 @@ def test_it_can_make_all_the_nodes
       [:multiline_block_quote, fence_length: 2, fence_offset: 0],
       [:escaped],
       [:wikilink, url: "www.yetto.app/billy.png"],
+      [:alert, type: :note],
     ]
     node_types.each do |type, arguments|
       node = arguments.nil? ? Commonmarker::Node.new(type) : Commonmarker::Node.new(type, **arguments)