add support for github style markdown alerts (#3626)

add support for github stype markdown alerts

Author: devoncarew

CHANGELOG.md

@@ -2,6 +2,8 @@
 
 * Remove explicit library names. (#3609)
 * No longer write the dartdoc version into generated html files.
+* Add support for GitHub markdown alert syntax
+  (https://docs.github.com/get-started/writing-on-github/getting-started-with-writing-and-formatting-on-github/basic-writing-and-formatting-syntax#alerts).
 
 ## 8.0.3
 

lib/resources/styles.css

@@ -1197,3 +1197,67 @@ li.inherited a {
    content: "" !important;
   }
 }
+
+/* github alert styles */
+
+.markdown-alert {
+  padding: .5rem 1rem;
+  border-left: 0.25em solid var(--main-sidebar-color);
+  margin-bottom: 1rem;
+}
+
+.markdown-body p {
+  margin-top: 0;
+  margin-bottom: 16px;
+}
+
+.markdown-alert>:last-child {
+  margin-bottom: 0;
+}
+
+.markdown-alert-title {
+  font-weight: 500;
+  color: var(--main-sidebar-color);
+}
+
+/* note, tip, important, warning, caution */
+
+.markdown-alert-note {
+  border-left-color: var(--main-hyperlinks-color);
+}
+
+.markdown-alert-note .markdown-alert-title {
+  color: var(--main-hyperlinks-color);
+}
+
+.markdown-alert-tip {
+  border-left-color: var(--main-var-color);
+}
+
+.markdown-alert-tip .markdown-alert-title {
+  color: var(--main-var-color);
+}
+
+.markdown-alert-important {
+  border-left-color: var(--main-tag-color);
+}
+
+.markdown-alert-important .markdown-alert-title {
+  color: var(--main-tag-color);
+}
+
+.markdown-alert-warning {
+  border-left-color: var(--main-string-color);
+}
+
+.markdown-alert-warning .markdown-alert-title {
+  color: var(--main-string-color);
+}
+
+.markdown-alert-caution {
+  border-left-color: var(--main-section-color);
+}
+
+.markdown-alert-caution .markdown-alert-title {
+  color: var(--main-section-color);
+}

lib/src/dartdoc.dart

@@ -250,9 +250,6 @@ class Dartdoc {
   }
 
   /// Runs [generateDocs] function and properly handles the errors.
-  ///
-  /// Passing in a [postProcessCallback] to do additional processing after
-  /// the documentation is generated.
   void executeGuarded() {
     onCheckProgress.listen(logProgress);
     // This function should *never* `await runZonedGuarded` because the errors

lib/src/markdown_processor.dart

@@ -132,6 +132,7 @@ final List<md.InlineSyntax> _markdownSyntaxes = [
 ];
 
 final List<md.BlockSyntax> _markdownBlockSyntaxes = [
+  const md.AlertBlockSyntax(),
   const md.FencedCodeBlockSyntax(),
   const md.HeaderWithIdSyntax(),
   const md.SetextHeaderWithIdSyntax(),

pubspec.yaml

@@ -14,7 +14,7 @@ dependencies:
   glob: ^2.1.1
   html: ^0.15.3
   logging: ^1.1.1
-  markdown: ^7.1.0
+  markdown: ^7.2.1
   meta: ^1.9.1
   package_config: ^2.1.0
   path: ^1.8.3