Merge pull request #823 from xoofx/fix-mermaid

Update DiagramExtension.cs
2026-02-09 05:49:12 +00:00 · 2024-10-25 22:01:40 +02:00 · 2024-10-25 21:58:28 +02:00 · 2024-10-01 20:53:47 +02:00 · 2024-09-26 13:51:18 +02:00 · 2024-07-18 06:50:19 +02:00
95 changed files with 1012 additions and 318 deletions
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -11,25 +11,8 @@ on:

 jobs:
  build:
-    runs-on: windows-latest
-
-    steps:
-    - name: Checkout
-      uses: actions/checkout@v2
-      with:
-        submodules: true
-        fetch-depth: 0
-
-    - name: Install .NET 6.0, 7.0, and 8.0
-      uses: actions/setup-dotnet@v1
-      with:
-        dotnet-version: |
-          6.0.x
-          7.0.x
-          8.0.x
-
-    - name: Build, Test, Pack, Publish
-      shell: bash
-      run: |
-        dotnet tool install -g dotnet-releaser
-        dotnet-releaser run --nuget-token "${{secrets.NUGET_TOKEN}}" --github-token "${{secrets.GITHUB_TOKEN}}" src/dotnet-releaser.toml
+    uses: xoofx/.github/.github/workflows/dotnet.yml@main
+    with:
+      dotnet-version: '6.0 8.0'
+    secrets:
+      NUGET_TOKEN: ${{ secrets.NUGET_TOKEN }}    
--- a/.github/workflows/nuget_org_only.config
+++ b/.github/workflows/nuget_org_only.config
@@ -0,0 +1,7 @@
+<?xml version="1.0" encoding="utf-8"?>
+<configuration>
+  <packageSources>
+    <clear />
+    <add key="nuget.org" value="https://api.nuget.org/v3/index.json" />
+  </packageSources>
+</configuration>
--- a/doc/parsing-extensions.md
+++ b/doc/parsing-extensions.md
@@ -1,6 +1,6 @@
 # Extensions and Parsers

-Markdig was [implemented in such a way](http://xoofx.com/blog/2016/06/13/implementing-a-markdown-processor-for-dotnet/) as to be extremely pluggable, with even basic behaviors being mutable and extendable.
+Markdig was [implemented in such a way](http://xoofx.github.io/blog/2016/06/13/implementing-a-markdown-processor-for-dotnet/) as to be extremely pluggable, with even basic behaviors being mutable and extendable.

 The basic mechanism for extension of Markdig is the `IMarkdownExtension` interface, which allows any implementing class to be registered with the pipeline builder and thus to directly modify the collections of `BlockParser` and `InlineParser` objects which end up in the pipeline.

--- a/readme.md
+++ b/readme.md
@@ -48,7 +48,7 @@ You can **try Markdig online** and compare it to other implementations on [babel
  - [**Emoji**](src/Markdig.Tests/Specs/EmojiSpecs.md) support (inspired from [Markdown-it](https://markdown-it.github.io/))
  - [**SmartyPants**](src/Markdig.Tests/Specs/SmartyPantsSpecs.md) (inspired from [Daring Fireball - SmartyPants](https://daringfireball.net/projects/smartypants/))
  - [**Bootstrap**](src/Markdig.Tests/Specs/BootstrapSpecs.md) class (to output bootstrap class)
-  - [**Diagrams**](src/Markdig.Tests/Specs/DiagramsSpecs.md) extension whenever a fenced code block contains a special keyword, it will be converted to a div block with the content as-is (currently, supports [`mermaid`](https://knsv.github.io/mermaid/) and [`nomnoml`](https://github.com/skanaar/nomnoml) diagrams)
+  - [**Diagrams**](src/Markdig.Tests/Specs/DiagramsSpecs.md) extension whenever a fenced code block contains a special keyword, it will be converted to a div block with the content as-is (currently, supports [`mermaid`](https://mermaid.js.org) and [`nomnoml`](https://github.com/skanaar/nomnoml) diagrams)
  - [**YAML Front Matter**](src/Markdig.Tests/Specs/YamlSpecs.md) to parse without evaluating the front matter and to discard it from the HTML output (typically used for previewing without the front matter in MarkdownEditor)
  - [**JIRA links**](src/Markdig.Tests/Specs/JiraLinks.md) to automatically generate links for JIRA project references (Thanks to @clarkd: https://github.com/clarkd/MarkdigJiraLinker)
 - Starting with Markdig version `0.20.0+`, Markdig is compatible only with `NETStandard 2.0`, `NETStandard 2.1`, `NETCoreApp 2.1` and `NETCoreApp 3.1`.
@@ -70,7 +70,7 @@ If you are looking for support for an old .NET Framework 3.5 or 4.0, you can dow

 While there is not yet a dedicated documentation, you can find from the [specs documentation](src/Markdig.Tests/Specs/readme.md) how to use these extensions.

-In the meantime, you can have a "behind the scene" article about Markdig in my blog post ["Implementing a Markdown Engine for .NET"](http://xoofx.com/blog/2016/06/13/implementing-a-markdown-processor-for-dotnet/)
+In the meantime, you can have a "behind the scene" article about Markdig in my blog post ["Implementing a Markdown Engine for .NET"](http://xoofx.github.io/blog/2016/06/13/implementing-a-markdown-processor-for-dotnet/)

 ## Download

@@ -164,4 +164,4 @@ Some decoding part (e.g HTML [EntityHelper.cs](https://github.com/lunet-io/markd
 Thanks to the work done by @clarkd on the JIRA Link extension (https://github.com/clarkd/MarkdigJiraLinker), now included with this project!
 ## Author

-Alexandre MUTEL aka [xoofx](http://xoofx.com)
+Alexandre MUTEL aka [xoofx](http://xoofx.github.io)
--- a/src/Markdig.Benchmarks/Markdig.Benchmarks.csproj
+++ b/src/Markdig.Benchmarks/Markdig.Benchmarks.csproj
@@ -1,6 +1,6 @@
-<Project Sdk="Microsoft.NET.Sdk">
+<Project Sdk="Microsoft.NET.Sdk">
  <PropertyGroup>
-    <TargetFramework>net6.0</TargetFramework>
+    <TargetFramework>net8.0</TargetFramework>
    <OutputType>Exe</OutputType>
    <AllowUnsafeBlocks>true</AllowUnsafeBlocks>
    <IsPackable>false</IsPackable>
@@ -19,12 +19,12 @@
    </Content>
  </ItemGroup>
  <ItemGroup>
-    <PackageReference Include="BenchmarkDotNet" Version="0.13.11" />
-    <PackageReference Include="BenchmarkDotNet.Diagnostics.Windows" Version="0.13.11" />
+    <PackageReference Include="BenchmarkDotNet" Version="0.13.12" />
+    <PackageReference Include="BenchmarkDotNet.Diagnostics.Windows" Version="0.13.12" />
    <PackageReference Include="CommonMark.NET" Version="0.15.1" />
    <PackageReference Include="Markdown" Version="2.2.1" />
    <PackageReference Include="MarkdownSharp" Version="2.0.5" />
-    <PackageReference Include="Microsoft.Diagnostics.Runtime" Version="3.1.456101" />
+    <PackageReference Include="Microsoft.Diagnostics.Runtime" Version="3.1.506101" />
  </ItemGroup>
  <ItemGroup>
    <ProjectReference Include="..\Markdig\Markdig.csproj" />
--- a/src/Markdig.Tests/Markdig.Tests.csproj
+++ b/src/Markdig.Tests/Markdig.Tests.csproj
@@ -1,18 +1,18 @@
 <Project Sdk="Microsoft.NET.Sdk">

  <PropertyGroup>
-    <TargetFrameworks>net6.0;net8.0</TargetFrameworks>
+    <TargetFramework>net8.0</TargetFramework>
    <OutputType>Exe</OutputType>
    <IsPackable>false</IsPackable>
    <ImplicitUsings>enable</ImplicitUsings>
    <StartupObject>Markdig.Tests.Program</StartupObject>
-    <SpecExecutable>$(MSBuildProjectDirectory)\..\SpecFileGen\bin\$(Configuration)\net6.0\SpecFileGen.dll</SpecExecutable>
-    <SpecTimestamp>$(MSBuildProjectDirectory)\..\SpecFileGen\bin\$(Configuration)\net6.0\SpecFileGen.timestamp</SpecTimestamp>
+    <SpecExecutable>$(MSBuildProjectDirectory)\..\SpecFileGen\bin\$(Configuration)\net8.0\SpecFileGen.dll</SpecExecutable>
+    <SpecTimestamp>$(MSBuildProjectDirectory)\..\SpecFileGen\bin\$(Configuration)\net8.0\SpecFileGen.timestamp</SpecTimestamp>
  </PropertyGroup>

  <ItemGroup>
-    <PackageReference Include="Microsoft.NET.Test.Sdk" Version="17.8.0" />
-    <PackageReference Include="NUnit" Version="4.0.1" />
+    <PackageReference Include="Microsoft.NET.Test.Sdk" Version="17.9.0" />
+    <PackageReference Include="NUnit" Version="4.1.0" />
    <PackageReference Include="NUnit3TestAdapter" Version="4.5.0" />
  </ItemGroup>

--- a/src/Markdig.Tests/Specs/AlertBlockSpecs.generated.cs
+++ b/src/Markdig.Tests/Specs/AlertBlockSpecs.generated.cs
@@ -0,0 +1,179 @@
+
+// --------------------------------
+//           Alert Blocks
+// --------------------------------
+
+using System;
+using NUnit.Framework;
+
+namespace Markdig.Tests.Specs.AlertBlocks
+{
+    [TestFixture]
+    public class TestExtensionsAlertBlocks
+    {
+        // # Extensions
+        // 
+        // This section describes the different extensions supported:
+        // 
+        // ## Alert Blocks
+        // 
+        // This is supporting the [GitHub Alert blocks](https://github.com/orgs/community/discussions/16925)
+        [Test]
+        public void ExtensionsAlertBlocks_Example001()
+        {
+            // Example 1
+            // Section: Extensions / Alert Blocks
+            //
+            // The following Markdown:
+            //     > [!NOTE]  
+            //     > Highlights information that users should take into account, even when skimming.
+            //     
+            //     > [!TIP]
+            //     > Optional information to help a user be more successful.
+            //     
+            //     > [!IMPORTANT]  
+            //     > Crucial information necessary for users to succeed.
+            //     
+            //     > [!WARNING]  
+            //     > Critical content demanding immediate user attention due to potential risks.
+            //     
+            //     > [!CAUTION]
+            //     > Negative potential consequences of an action.
+            //
+            // Should be rendered as:
+            //     <div class="markdown-alert markdown-alert-note">
+            //     <p class="markdown-alert-title"><svg viewBox="0 0 16 16" version="1.1" width="16" height="16" aria-hidden="true"><path d="M0 8a8 8 0 1 1 16 0A8 8 0 0 1 0 8Zm8-6.5a6.5 6.5 0 1 0 0 13 6.5 6.5 0 0 0 0-13ZM6.5 7.75A.75.75 0 0 1 7.25 7h1a.75.75 0 0 1 .75.75v2.75h.25a.75.75 0 0 1 0 1.5h-2a.75.75 0 0 1 0-1.5h.25v-2h-.25a.75.75 0 0 1-.75-.75ZM8 6a1 1 0 1 1 0-2 1 1 0 0 1 0 2Z"></path></svg>Note</p>
+            //     <p>Highlights information that users should take into account, even when skimming.</p>
+            //     </div>
+            //     <div class="markdown-alert markdown-alert-tip">
+            //     <p class="markdown-alert-title"><svg viewBox="0 0 16 16" version="1.1" width="16" height="16" aria-hidden="true"><path d="M8 1.5c-2.363 0-4 1.69-4 3.75 0 .984.424 1.625.984 2.304l.214.253c.223.264.47.556.673.848.284.411.537.896.621 1.49a.75.75 0 0 1-1.484.211c-.04-.282-.163-.547-.37-.847a8.456 8.456 0 0 0-.542-.68c-.084-.1-.173-.205-.268-.32C3.201 7.75 2.5 6.766 2.5 5.25 2.5 2.31 4.863 0 8 0s5.5 2.31 5.5 5.25c0 1.516-.701 2.5-1.328 3.259-.095.115-.184.22-.268.319-.207.245-.383.453-.541.681-.208.3-.33.565-.37.847a.751.751 0 0 1-1.485-.212c.084-.593.337-1.078.621-1.489.203-.292.45-.584.673-.848.075-.088.147-.173.213-.253.561-.679.985-1.32.985-2.304 0-2.06-1.637-3.75-4-3.75ZM5.75 12h4.5a.75.75 0 0 1 0 1.5h-4.5a.75.75 0 0 1 0-1.5ZM6 15.25a.75.75 0 0 1 .75-.75h2.5a.75.75 0 0 1 0 1.5h-2.5a.75.75 0 0 1-.75-.75Z"></path></svg>Tip</p>
+            //     <p>Optional information to help a user be more successful.</p>
+            //     </div>
+            //     <div class="markdown-alert markdown-alert-important">
+            //     <p class="markdown-alert-title"><svg viewBox="0 0 16 16" version="1.1" width="16" height="16" aria-hidden="true"><path d="M0 1.75C0 .784.784 0 1.75 0h12.5C15.216 0 16 .784 16 1.75v9.5A1.75 1.75 0 0 1 14.25 13H8.06l-2.573 2.573A1.458 1.458 0 0 1 3 14.543V13H1.75A1.75 1.75 0 0 1 0 11.25Zm1.75-.25a.25.25 0 0 0-.25.25v9.5c0 .138.112.25.25.25h2a.75.75 0 0 1 .75.75v2.19l2.72-2.72a.749.749 0 0 1 .53-.22h6.5a.25.25 0 0 0 .25-.25v-9.5a.25.25 0 0 0-.25-.25Zm7 2.25v2.5a.75.75 0 0 1-1.5 0v-2.5a.75.75 0 0 1 1.5 0ZM9 9a1 1 0 1 1-2 0 1 1 0 0 1 2 0Z"></path></svg>Important</p>
+            //     <p>Crucial information necessary for users to succeed.</p>
+            //     </div>
+            //     <div class="markdown-alert markdown-alert-warning">
+            //     <p class="markdown-alert-title"><svg viewBox="0 0 16 16" version="1.1" width="16" height="16" aria-hidden="true"><path d="M6.457 1.047c.659-1.234 2.427-1.234 3.086 0l6.082 11.378A1.75 1.75 0 0 1 14.082 15H1.918a1.75 1.75 0 0 1-1.543-2.575Zm1.763.707a.25.25 0 0 0-.44 0L1.698 13.132a.25.25 0 0 0 .22.368h12.164a.25.25 0 0 0 .22-.368Zm.53 3.996v2.5a.75.75 0 0 1-1.5 0v-2.5a.75.75 0 0 1 1.5 0ZM9 11a1 1 0 1 1-2 0 1 1 0 0 1 2 0Z"></path></svg>Warning</p>
+            //     <p>Critical content demanding immediate user attention due to potential risks.</p>
+            //     </div>
+            //     <div class="markdown-alert markdown-alert-caution">
+            //     <p class="markdown-alert-title"><svg viewBox="0 0 16 16" version="1.1" width="16" height="16" aria-hidden="true"><path d="M4.47.22A.749.749 0 0 1 5 0h6c.199 0 .389.079.53.22l4.25 4.25c.141.14.22.331.22.53v6a.749.749 0 0 1-.22.53l-4.25 4.25A.749.749 0 0 1 11 16H5a.749.749 0 0 1-.53-.22L.22 11.53A.749.749 0 0 1 0 11V5c0-.199.079-.389.22-.53Zm.84 1.28L1.5 5.31v5.38l3.81 3.81h5.38l3.81-3.81V5.31L10.69 1.5ZM8 4a.75.75 0 0 1 .75.75v3.5a.75.75 0 0 1-1.5 0v-3.5A.75.75 0 0 1 8 4Zm0 8a1 1 0 1 1 0-2 1 1 0 0 1 0 2Z"></path></svg>Caution</p>
+            //     <p>Negative potential consequences of an action.</p>
+            //     </div>
+
+            TestParser.TestSpec("> [!NOTE]  \n> Highlights information that users should take into account, even when skimming.\n\n> [!TIP]\n> Optional information to help a user be more successful.\n\n> [!IMPORTANT]  \n> Crucial information necessary for users to succeed.\n\n> [!WARNING]  \n> Critical content demanding immediate user attention due to potential risks.\n\n> [!CAUTION]\n> Negative potential consequences of an action.", "<div class=\"markdown-alert markdown-alert-note\">\n<p class=\"markdown-alert-title\"><svg viewBox=\"0 0 16 16\" version=\"1.1\" width=\"16\" height=\"16\" aria-hidden=\"true\"><path d=\"M0 8a8 8 0 1 1 16 0A8 8 0 0 1 0 8Zm8-6.5a6.5 6.5 0 1 0 0 13 6.5 6.5 0 0 0 0-13ZM6.5 7.75A.75.75 0 0 1 7.25 7h1a.75.75 0 0 1 .75.75v2.75h.25a.75.75 0 0 1 0 1.5h-2a.75.75 0 0 1 0-1.5h.25v-2h-.25a.75.75 0 0 1-.75-.75ZM8 6a1 1 0 1 1 0-2 1 1 0 0 1 0 2Z\"></path></svg>Note</p>\n<p>Highlights information that users should take into account, even when skimming.</p>\n</div>\n<div class=\"markdown-alert markdown-alert-tip\">\n<p class=\"markdown-alert-title\"><svg viewBox=\"0 0 16 16\" version=\"1.1\" width=\"16\" height=\"16\" aria-hidden=\"true\"><path d=\"M8 1.5c-2.363 0-4 1.69-4 3.75 0 .984.424 1.625.984 2.304l.214.253c.223.264.47.556.673.848.284.411.537.896.621 1.49a.75.75 0 0 1-1.484.211c-.04-.282-.163-.547-.37-.847a8.456 8.456 0 0 0-.542-.68c-.084-.1-.173-.205-.268-.32C3.201 7.75 2.5 6.766 2.5 5.25 2.5 2.31 4.863 0 8 0s5.5 2.31 5.5 5.25c0 1.516-.701 2.5-1.328 3.259-.095.115-.184.22-.268.319-.207.245-.383.453-.541.681-.208.3-.33.565-.37.847a.751.751 0 0 1-1.485-.212c.084-.593.337-1.078.621-1.489.203-.292.45-.584.673-.848.075-.088.147-.173.213-.253.561-.679.985-1.32.985-2.304 0-2.06-1.637-3.75-4-3.75ZM5.75 12h4.5a.75.75 0 0 1 0 1.5h-4.5a.75.75 0 0 1 0-1.5ZM6 15.25a.75.75 0 0 1 .75-.75h2.5a.75.75 0 0 1 0 1.5h-2.5a.75.75 0 0 1-.75-.75Z\"></path></svg>Tip</p>\n<p>Optional information to help a user be more successful.</p>\n</div>\n<div class=\"markdown-alert markdown-alert-important\">\n<p class=\"markdown-alert-title\"><svg viewBox=\"0 0 16 16\" version=\"1.1\" width=\"16\" height=\"16\" aria-hidden=\"true\"><path d=\"M0 1.75C0 .784.784 0 1.75 0h12.5C15.216 0 16 .784 16 1.75v9.5A1.75 1.75 0 0 1 14.25 13H8.06l-2.573 2.573A1.458 1.458 0 0 1 3 14.543V13H1.75A1.75 1.75 0 0 1 0 11.25Zm1.75-.25a.25.25 0 0 0-.25.25v9.5c0 .138.112.25.25.25h2a.75.75 0 0 1 .75.75v2.19l2.72-2.72a.749.749 0 0 1 .53-.22h6.5a.25.25 0 0 0 .25-.25v-9.5a.25.25 0 0 0-.25-.25Zm7 2.25v2.5a.75.75 0 0 1-1.5 0v-2.5a.75.75 0 0 1 1.5 0ZM9 9a1 1 0 1 1-2 0 1 1 0 0 1 2 0Z\"></path></svg>Important</p>\n<p>Crucial information necessary for users to succeed.</p>\n</div>\n<div class=\"markdown-alert markdown-alert-warning\">\n<p class=\"markdown-alert-title\"><svg viewBox=\"0 0 16 16\" version=\"1.1\" width=\"16\" height=\"16\" aria-hidden=\"true\"><path d=\"M6.457 1.047c.659-1.234 2.427-1.234 3.086 0l6.082 11.378A1.75 1.75 0 0 1 14.082 15H1.918a1.75 1.75 0 0 1-1.543-2.575Zm1.763.707a.25.25 0 0 0-.44 0L1.698 13.132a.25.25 0 0 0 .22.368h12.164a.25.25 0 0 0 .22-.368Zm.53 3.996v2.5a.75.75 0 0 1-1.5 0v-2.5a.75.75 0 0 1 1.5 0ZM9 11a1 1 0 1 1-2 0 1 1 0 0 1 2 0Z\"></path></svg>Warning</p>\n<p>Critical content demanding immediate user attention due to potential risks.</p>\n</div>\n<div class=\"markdown-alert markdown-alert-caution\">\n<p class=\"markdown-alert-title\"><svg viewBox=\"0 0 16 16\" version=\"1.1\" width=\"16\" height=\"16\" aria-hidden=\"true\"><path d=\"M4.47.22A.749.749 0 0 1 5 0h6c.199 0 .389.079.53.22l4.25 4.25c.141.14.22.331.22.53v6a.749.749 0 0 1-.22.53l-4.25 4.25A.749.749 0 0 1 11 16H5a.749.749 0 0 1-.53-.22L.22 11.53A.749.749 0 0 1 0 11V5c0-.199.079-.389.22-.53Zm.84 1.28L1.5 5.31v5.38l3.81 3.81h5.38l3.81-3.81V5.31L10.69 1.5ZM8 4a.75.75 0 0 1 .75.75v3.5a.75.75 0 0 1-1.5 0v-3.5A.75.75 0 0 1 8 4Zm0 8a1 1 0 1 1 0-2 1 1 0 0 1 0 2Z\"></path></svg>Caution</p>\n<p>Negative potential consequences of an action.</p>\n</div>", "advanced", context: "Example 1\nSection Extensions / Alert Blocks\n");
+        }
+
+        // Example with code blocks and mix formatting:
+        [Test]
+        public void ExtensionsAlertBlocks_Example002()
+        {
+            // Example 2
+            // Section: Extensions / Alert Blocks
+            //
+            // The following Markdown:
+            //     > [!NOTE]
+            //     > Highlights information that users should take into account, even when skimming.
+            //     > Testing rendering for multiple lines
+            //     > ```csharp
+            //     > var test = "I can also add code to panels
+            //     > ```
+            //     > `Inline code testing`
+            //
+            // Should be rendered as:
+            //     <div class="markdown-alert markdown-alert-note">
+            //     <p class="markdown-alert-title"><svg viewBox="0 0 16 16" version="1.1" width="16" height="16" aria-hidden="true"><path d="M0 8a8 8 0 1 1 16 0A8 8 0 0 1 0 8Zm8-6.5a6.5 6.5 0 1 0 0 13 6.5 6.5 0 0 0 0-13ZM6.5 7.75A.75.75 0 0 1 7.25 7h1a.75.75 0 0 1 .75.75v2.75h.25a.75.75 0 0 1 0 1.5h-2a.75.75 0 0 1 0-1.5h.25v-2h-.25a.75.75 0 0 1-.75-.75ZM8 6a1 1 0 1 1 0-2 1 1 0 0 1 0 2Z"></path></svg>Note</p>
+            //     <p>Highlights information that users should take into account, even when skimming.
+            //     Testing rendering for multiple lines</p>
+            //     <pre><code class="language-csharp">var test = &quot;I can also add code to panels
+            //     </code></pre>
+            //     <p><code>Inline code testing</code></p>
+            //     </div>
+
+            TestParser.TestSpec("> [!NOTE]\n> Highlights information that users should take into account, even when skimming.\n> Testing rendering for multiple lines\n> ```csharp\n> var test = \"I can also add code to panels\n> ```\n> `Inline code testing`", "<div class=\"markdown-alert markdown-alert-note\">\n<p class=\"markdown-alert-title\"><svg viewBox=\"0 0 16 16\" version=\"1.1\" width=\"16\" height=\"16\" aria-hidden=\"true\"><path d=\"M0 8a8 8 0 1 1 16 0A8 8 0 0 1 0 8Zm8-6.5a6.5 6.5 0 1 0 0 13 6.5 6.5 0 0 0 0-13ZM6.5 7.75A.75.75 0 0 1 7.25 7h1a.75.75 0 0 1 .75.75v2.75h.25a.75.75 0 0 1 0 1.5h-2a.75.75 0 0 1 0-1.5h.25v-2h-.25a.75.75 0 0 1-.75-.75ZM8 6a1 1 0 1 1 0-2 1 1 0 0 1 0 2Z\"></path></svg>Note</p>\n<p>Highlights information that users should take into account, even when skimming.\nTesting rendering for multiple lines</p>\n<pre><code class=\"language-csharp\">var test = &quot;I can also add code to panels\n</code></pre>\n<p><code>Inline code testing</code></p>\n</div>", "advanced", context: "Example 2\nSection Extensions / Alert Blocks\n");
+        }
+
+        // Multiline:
+        [Test]
+        public void ExtensionsAlertBlocks_Example003()
+        {
+            // Example 3
+            // Section: Extensions / Alert Blocks
+            //
+            // The following Markdown:
+            //     > [!NOTE]
+            //     > Highlights information that users should take into account, even when skimming.
+            //     > 
+            //     > Testing rendering for multiple lines
+            //     > 
+            //     > `Inline code testing`
+            //     > 
+            //     > Other line
+            //     > 
+            //     > > Nested quote
+            //     > >
+            //     > > Final nested quote line
+            //     > 
+            //     > Final line of alert
+            //
+            // Should be rendered as:
+            //     <div class="markdown-alert markdown-alert-note">
+            //     <p class="markdown-alert-title"><svg viewBox="0 0 16 16" version="1.1" width="16" height="16" aria-hidden="true"><path d="M0 8a8 8 0 1 1 16 0A8 8 0 0 1 0 8Zm8-6.5a6.5 6.5 0 1 0 0 13 6.5 6.5 0 0 0 0-13ZM6.5 7.75A.75.75 0 0 1 7.25 7h1a.75.75 0 0 1 .75.75v2.75h.25a.75.75 0 0 1 0 1.5h-2a.75.75 0 0 1 0-1.5h.25v-2h-.25a.75.75 0 0 1-.75-.75ZM8 6a1 1 0 1 1 0-2 1 1 0 0 1 0 2Z"></path></svg>Note</p>
+            //     <p>Highlights information that users should take into account, even when skimming.</p>
+            //     <p>Testing rendering for multiple lines</p>
+            //     <p><code>Inline code testing</code></p>
+            //     <p>Other line</p>
+            //     <blockquote>
+            //     <p>Nested quote</p>
+            //     <p>Final nested quote line</p>
+            //     </blockquote>
+            //     <p>Final line of alert</p>
+            //     </div>
+
+            TestParser.TestSpec("> [!NOTE]\n> Highlights information that users should take into account, even when skimming.\n> \n> Testing rendering for multiple lines\n> \n> `Inline code testing`\n> \n> Other line\n> \n> > Nested quote\n> >\n> > Final nested quote line\n> \n> Final line of alert", "<div class=\"markdown-alert markdown-alert-note\">\n<p class=\"markdown-alert-title\"><svg viewBox=\"0 0 16 16\" version=\"1.1\" width=\"16\" height=\"16\" aria-hidden=\"true\"><path d=\"M0 8a8 8 0 1 1 16 0A8 8 0 0 1 0 8Zm8-6.5a6.5 6.5 0 1 0 0 13 6.5 6.5 0 0 0 0-13ZM6.5 7.75A.75.75 0 0 1 7.25 7h1a.75.75 0 0 1 .75.75v2.75h.25a.75.75 0 0 1 0 1.5h-2a.75.75 0 0 1 0-1.5h.25v-2h-.25a.75.75 0 0 1-.75-.75ZM8 6a1 1 0 1 1 0-2 1 1 0 0 1 0 2Z\"></path></svg>Note</p>\n<p>Highlights information that users should take into account, even when skimming.</p>\n<p>Testing rendering for multiple lines</p>\n<p><code>Inline code testing</code></p>\n<p>Other line</p>\n<blockquote>\n<p>Nested quote</p>\n<p>Final nested quote line</p>\n</blockquote>\n<p>Final line of alert</p>\n</div>", "advanced", context: "Example 3\nSection Extensions / Alert Blocks\n");
+        }
+
+        // An alert inline (e.g `[!NOTE]`) must come first in a quote block, and must be followed by optional spaces with a new line. If no new lines are found, it will not be considered as an alert block.
+        // 
+        // Followed by space and new line:
+        [Test]
+        public void ExtensionsAlertBlocks_Example004()
+        {
+            // Example 4
+            // Section: Extensions / Alert Blocks
+            //
+            // The following Markdown:
+            //     > [!NOTE] This is invalid because no new line
+            //     > Highlights information that users should take into account, even when skimming.
+            //
+            // Should be rendered as:
+            //     <blockquote>
+            //     <p>[!NOTE] This is invalid because no new line
+            //     Highlights information that users should take into account, even when skimming.</p>
+            //     </blockquote>
+
+            TestParser.TestSpec("> [!NOTE] This is invalid because no new line\n> Highlights information that users should take into account, even when skimming.", "<blockquote>\n<p>[!NOTE] This is invalid because no new line\nHighlights information that users should take into account, even when skimming.</p>\n</blockquote>", "advanced", context: "Example 4\nSection Extensions / Alert Blocks\n");
+        }
+
+        // Must come first in a quote block:
+        [Test]
+        public void ExtensionsAlertBlocks_Example005()
+        {
+            // Example 5
+            // Section: Extensions / Alert Blocks
+            //
+            // The following Markdown:
+            //     > This is not a [!NOTE]
+            //     > Highlights information that users should take into account, even when skimming.
+            //
+            // Should be rendered as:
+            //     <blockquote>
+            //     <p>This is not a [!NOTE]
+            //     Highlights information that users should take into account, even when skimming.</p>
+            //     </blockquote>
+
+            TestParser.TestSpec("> This is not a [!NOTE]\n> Highlights information that users should take into account, even when skimming.", "<blockquote>\n<p>This is not a [!NOTE]\nHighlights information that users should take into account, even when skimming.</p>\n</blockquote>", "advanced", context: "Example 5\nSection Extensions / Alert Blocks\n");
+        }
+    }
+}
--- a/src/Markdig.Tests/Specs/AlertBlockSpecs.md
+++ b/src/Markdig.Tests/Specs/AlertBlockSpecs.md
@@ -0,0 +1,127 @@
+# Extensions
+
+This section describes the different extensions supported:
+
+## Alert Blocks
+
+This is supporting the [GitHub Alert blocks](https://github.com/orgs/community/discussions/16925)
+
+```````````````````````````````` example
+> [!NOTE]  
+> Highlights information that users should take into account, even when skimming.
+
+> [!TIP]
+> Optional information to help a user be more successful.
+
+> [!IMPORTANT]  
+> Crucial information necessary for users to succeed.
+
+> [!WARNING]  
+> Critical content demanding immediate user attention due to potential risks.
+
+> [!CAUTION]
+> Negative potential consequences of an action.
+.
+<div class="markdown-alert markdown-alert-note">
+<p class="markdown-alert-title"><svg viewBox="0 0 16 16" version="1.1" width="16" height="16" aria-hidden="true"><path d="M0 8a8 8 0 1 1 16 0A8 8 0 0 1 0 8Zm8-6.5a6.5 6.5 0 1 0 0 13 6.5 6.5 0 0 0 0-13ZM6.5 7.75A.75.75 0 0 1 7.25 7h1a.75.75 0 0 1 .75.75v2.75h.25a.75.75 0 0 1 0 1.5h-2a.75.75 0 0 1 0-1.5h.25v-2h-.25a.75.75 0 0 1-.75-.75ZM8 6a1 1 0 1 1 0-2 1 1 0 0 1 0 2Z"></path></svg>Note</p>
+<p>Highlights information that users should take into account, even when skimming.</p>
+</div>
+<div class="markdown-alert markdown-alert-tip">
+<p class="markdown-alert-title"><svg viewBox="0 0 16 16" version="1.1" width="16" height="16" aria-hidden="true"><path d="M8 1.5c-2.363 0-4 1.69-4 3.75 0 .984.424 1.625.984 2.304l.214.253c.223.264.47.556.673.848.284.411.537.896.621 1.49a.75.75 0 0 1-1.484.211c-.04-.282-.163-.547-.37-.847a8.456 8.456 0 0 0-.542-.68c-.084-.1-.173-.205-.268-.32C3.201 7.75 2.5 6.766 2.5 5.25 2.5 2.31 4.863 0 8 0s5.5 2.31 5.5 5.25c0 1.516-.701 2.5-1.328 3.259-.095.115-.184.22-.268.319-.207.245-.383.453-.541.681-.208.3-.33.565-.37.847a.751.751 0 0 1-1.485-.212c.084-.593.337-1.078.621-1.489.203-.292.45-.584.673-.848.075-.088.147-.173.213-.253.561-.679.985-1.32.985-2.304 0-2.06-1.637-3.75-4-3.75ZM5.75 12h4.5a.75.75 0 0 1 0 1.5h-4.5a.75.75 0 0 1 0-1.5ZM6 15.25a.75.75 0 0 1 .75-.75h2.5a.75.75 0 0 1 0 1.5h-2.5a.75.75 0 0 1-.75-.75Z"></path></svg>Tip</p>
+<p>Optional information to help a user be more successful.</p>
+</div>
+<div class="markdown-alert markdown-alert-important">
+<p class="markdown-alert-title"><svg viewBox="0 0 16 16" version="1.1" width="16" height="16" aria-hidden="true"><path d="M0 1.75C0 .784.784 0 1.75 0h12.5C15.216 0 16 .784 16 1.75v9.5A1.75 1.75 0 0 1 14.25 13H8.06l-2.573 2.573A1.458 1.458 0 0 1 3 14.543V13H1.75A1.75 1.75 0 0 1 0 11.25Zm1.75-.25a.25.25 0 0 0-.25.25v9.5c0 .138.112.25.25.25h2a.75.75 0 0 1 .75.75v2.19l2.72-2.72a.749.749 0 0 1 .53-.22h6.5a.25.25 0 0 0 .25-.25v-9.5a.25.25 0 0 0-.25-.25Zm7 2.25v2.5a.75.75 0 0 1-1.5 0v-2.5a.75.75 0 0 1 1.5 0ZM9 9a1 1 0 1 1-2 0 1 1 0 0 1 2 0Z"></path></svg>Important</p>
+<p>Crucial information necessary for users to succeed.</p>
+</div>
+<div class="markdown-alert markdown-alert-warning">
+<p class="markdown-alert-title"><svg viewBox="0 0 16 16" version="1.1" width="16" height="16" aria-hidden="true"><path d="M6.457 1.047c.659-1.234 2.427-1.234 3.086 0l6.082 11.378A1.75 1.75 0 0 1 14.082 15H1.918a1.75 1.75 0 0 1-1.543-2.575Zm1.763.707a.25.25 0 0 0-.44 0L1.698 13.132a.25.25 0 0 0 .22.368h12.164a.25.25 0 0 0 .22-.368Zm.53 3.996v2.5a.75.75 0 0 1-1.5 0v-2.5a.75.75 0 0 1 1.5 0ZM9 11a1 1 0 1 1-2 0 1 1 0 0 1 2 0Z"></path></svg>Warning</p>
+<p>Critical content demanding immediate user attention due to potential risks.</p>
+</div>
+<div class="markdown-alert markdown-alert-caution">
+<p class="markdown-alert-title"><svg viewBox="0 0 16 16" version="1.1" width="16" height="16" aria-hidden="true"><path d="M4.47.22A.749.749 0 0 1 5 0h6c.199 0 .389.079.53.22l4.25 4.25c.141.14.22.331.22.53v6a.749.749 0 0 1-.22.53l-4.25 4.25A.749.749 0 0 1 11 16H5a.749.749 0 0 1-.53-.22L.22 11.53A.749.749 0 0 1 0 11V5c0-.199.079-.389.22-.53Zm.84 1.28L1.5 5.31v5.38l3.81 3.81h5.38l3.81-3.81V5.31L10.69 1.5ZM8 4a.75.75 0 0 1 .75.75v3.5a.75.75 0 0 1-1.5 0v-3.5A.75.75 0 0 1 8 4Zm0 8a1 1 0 1 1 0-2 1 1 0 0 1 0 2Z"></path></svg>Caution</p>
+<p>Negative potential consequences of an action.</p>
+</div>
+````````````````````````````````
+
+Example with code blocks and mix formatting:
+
+
+```````````````````````````````` example
+> [!NOTE]
+> Highlights information that users should take into account, even when skimming.
+> Testing rendering for multiple lines
+> ```csharp
+> var test = "I can also add code to panels
+> ```
+> `Inline code testing`
+.
+<div class="markdown-alert markdown-alert-note">
+<p class="markdown-alert-title"><svg viewBox="0 0 16 16" version="1.1" width="16" height="16" aria-hidden="true"><path d="M0 8a8 8 0 1 1 16 0A8 8 0 0 1 0 8Zm8-6.5a6.5 6.5 0 1 0 0 13 6.5 6.5 0 0 0 0-13ZM6.5 7.75A.75.75 0 0 1 7.25 7h1a.75.75 0 0 1 .75.75v2.75h.25a.75.75 0 0 1 0 1.5h-2a.75.75 0 0 1 0-1.5h.25v-2h-.25a.75.75 0 0 1-.75-.75ZM8 6a1 1 0 1 1 0-2 1 1 0 0 1 0 2Z"></path></svg>Note</p>
+<p>Highlights information that users should take into account, even when skimming.
+Testing rendering for multiple lines</p>
+<pre><code class="language-csharp">var test = &quot;I can also add code to panels
+</code></pre>
+<p><code>Inline code testing</code></p>
+</div>
+````````````````````````````````
+
+Multiline:
+
+```````````````````````````````` example
+> [!NOTE]
+> Highlights information that users should take into account, even when skimming.
+> 
+> Testing rendering for multiple lines
+> 
+> `Inline code testing`
+> 
+> Other line
+> 
+> > Nested quote
+> >
+> > Final nested quote line
+> 
+> Final line of alert
+.
+<div class="markdown-alert markdown-alert-note">
+<p class="markdown-alert-title"><svg viewBox="0 0 16 16" version="1.1" width="16" height="16" aria-hidden="true"><path d="M0 8a8 8 0 1 1 16 0A8 8 0 0 1 0 8Zm8-6.5a6.5 6.5 0 1 0 0 13 6.5 6.5 0 0 0 0-13ZM6.5 7.75A.75.75 0 0 1 7.25 7h1a.75.75 0 0 1 .75.75v2.75h.25a.75.75 0 0 1 0 1.5h-2a.75.75 0 0 1 0-1.5h.25v-2h-.25a.75.75 0 0 1-.75-.75ZM8 6a1 1 0 1 1 0-2 1 1 0 0 1 0 2Z"></path></svg>Note</p>
+<p>Highlights information that users should take into account, even when skimming.</p>
+<p>Testing rendering for multiple lines</p>
+<p><code>Inline code testing</code></p>
+<p>Other line</p>
+<blockquote>
+<p>Nested quote</p>
+<p>Final nested quote line</p>
+</blockquote>
+<p>Final line of alert</p>
+</div>
+````````````````````````````````
+
+An alert inline (e.g `[!NOTE]`) must come first in a quote block, and must be followed by optional spaces with a new line. If no new lines are found, it will not be considered as an alert block.
+
+Followed by space and new line:
+
+```````````````````````````````` example
+> [!NOTE] This is invalid because no new line
+> Highlights information that users should take into account, even when skimming.
+.
+<blockquote>
+<p>[!NOTE] This is invalid because no new line
+Highlights information that users should take into account, even when skimming.</p>
+</blockquote>
+````````````````````````````````
+
+Must come first in a quote block:
+
+```````````````````````````````` example
+> This is not a [!NOTE]
+> Highlights information that users should take into account, even when skimming.
+.
+<blockquote>
+<p>This is not a [!NOTE]
+Highlights information that users should take into account, even when skimming.</p>
+</blockquote>
+````````````````````````````````
+
+
--- a/src/Markdig.Tests/Specs/DiagramsSpecs.generated.cs
+++ b/src/Markdig.Tests/Specs/DiagramsSpecs.generated.cs
@@ -17,7 +17,7 @@ namespace Markdig.Tests.Specs.Diagrams
        // 
        // ## Mermaid diagrams
        //  
-        // Using a fenced code block with the `mermaid` language info will output a `<div class='mermaid'>` instead of a `pre/code` block:
+        // Using a fenced code block with the `mermaid` language info will output a `<pre class='mermaid'>` block (which is the default for other code block):
        [Test]
        public void ExtensionsMermaidDiagrams_Example001()
        {
@@ -34,14 +34,14 @@ namespace Markdig.Tests.Specs.Diagrams
            //     ```
            //
            // Should be rendered as:
-            //     <div class="mermaid">graph TD;
+            //     <pre class="mermaid">graph TD;
            //         A-->B;
            //         A-->C;
            //         B-->D;
            //         C-->D;
-            //     </div>
+            //     </pre>

-            TestParser.TestSpec("```mermaid\ngraph TD;\n    A-->B;\n    A-->C;\n    B-->D;\n    C-->D;\n```", "<div class=\"mermaid\">graph TD;\n    A-->B;\n    A-->C;\n    B-->D;\n    C-->D;\n</div>", "diagrams|advanced", context: "Example 1\nSection Extensions / Mermaid diagrams\n");
+            TestParser.TestSpec("```mermaid\ngraph TD;\n    A-->B;\n    A-->C;\n    B-->D;\n    C-->D;\n```", "<pre class=\"mermaid\">graph TD;\n    A-->B;\n    A-->C;\n    B-->D;\n    C-->D;\n</pre>", "diagrams|advanced", context: "Example 1\nSection Extensions / Mermaid diagrams\n");
        }
    }

--- a/src/Markdig.Tests/Specs/DiagramsSpecs.md
+++ b/src/Markdig.Tests/Specs/DiagramsSpecs.md
@@ -4,7 +4,7 @@ Adds support for diagrams extension:

 ## Mermaid diagrams
 
-Using a fenced code block with the `mermaid` language info will output a `<div class='mermaid'>` instead of a `pre/code` block:
+Using a fenced code block with the `mermaid` language info will output a `<pre class='mermaid'>` block (which is the default for other code block):

 ```````````````````````````````` example
 ```mermaid
@@ -15,12 +15,12 @@ graph TD;
    C-->D;
 ```
 .
-<div class="mermaid">graph TD;
+<pre class="mermaid">graph TD;
    A-->B;
    A-->C;
    B-->D;
    C-->D;
-</div>
+</pre>
 ````````````````````````````````

 ## nomnoml diagrams
--- a/src/Markdig.Tests/Specs/MathSpecs.generated.cs
+++ b/src/Markdig.Tests/Specs/MathSpecs.generated.cs
@@ -279,7 +279,7 @@ namespace Markdig.Tests.Specs.Math
    {
        // ## Math Block
        // 
-        // The match block can spawn on multiple lines by having a $$ starting on a line.
+        // The math block can spawn on multiple lines by having a $$ starting on a line.
        // It is working as a fenced code block.
        [Test]
        public void ExtensionsMathBlock_Example017()
--- a/src/Markdig.Tests/Specs/MathSpecs.md
+++ b/src/Markdig.Tests/Specs/MathSpecs.md
@@ -127,7 +127,7 @@ $$ math $$ starting at a line

 ## Math Block

-The match block can spawn on multiple lines by having a $$ starting on a line.
+The math block can spawn on multiple lines by having a $$ starting on a line.
 It is working as a fenced code block.

 ```````````````````````````````` example
--- a/src/Markdig.Tests/TestMediaLinks.cs
+++ b/src/Markdig.Tests/TestMediaLinks.cs
@@ -25,6 +25,7 @@ public class TestMediaLinks
    [Test]
    [TestCase("![static mp4](https://sample.com/video.mp4)", "<p><video width=\"500\" height=\"281\" controls=\"\"><source type=\"video/mp4\" src=\"https://sample.com/video.mp4\"></source></video></p>\n")]
    [TestCase("![static mp4](//sample.com/video.mp4)", "<p><video width=\"500\" height=\"281\" controls=\"\"><source type=\"video/mp4\" src=\"//sample.com/video.mp4\"></source></video></p>\n")]
+    [TestCase(@"![youtube short](https://www.youtube.com/shorts/6BUptHVuvyI?feature=share)", "<p><iframe src=\"https://www.youtube.com/embed/6BUptHVuvyI\" class=\"youtubeshort\" width=\"500\" height=\"281\" frameborder=\"0\" allowfullscreen=\"\"></iframe></p>\n")]
    [TestCase(@"![youtube.com](https://www.youtube.com/watch?v=mswPy5bt3TQ)", "<p><iframe src=\"https://www.youtube.com/embed/mswPy5bt3TQ\" class=\"youtube\" width=\"500\" height=\"281\" frameborder=\"0\" allowfullscreen=\"\"></iframe></p>\n")]
    [TestCase("![yandex.ru](https://music.yandex.ru/album/411845/track/4402274)", "<p><iframe src=\"https://music.yandex.ru/iframe/#track/4402274/411845/\" class=\"yandex\" width=\"500\" height=\"281\" frameborder=\"0\"></iframe></p>\n")]
    [TestCase("![vimeo](https://vimeo.com/8607834)", "<p><iframe src=\"https://player.vimeo.com/video/8607834\" class=\"vimeo\" width=\"500\" height=\"281\" frameborder=\"0\" allowfullscreen=\"\"></iframe></p>\n")]
@@ -33,7 +34,7 @@ public class TestMediaLinks
    public void TestBuiltInHosts(string markdown, string expected)
    {
        string html = Markdown.ToHtml(markdown, GetPipeline());
-        Assert.AreEqual(html, expected);
+        Assert.AreEqual(expected, html);
    }

    [TestCase("![static video relative path](./video.mp4)",
@@ -43,7 +44,7 @@ public class TestMediaLinks
    public void TestBuiltInHostsWithRelativePaths(string markdown, string expected)
    {
        string html = Markdown.ToHtml(markdown, GetPipeline());
-        Assert.AreEqual(html, expected);
+        Assert.AreEqual(expected, html);
    }
    
    private class TestHostProvider : IHostProvider
--- a/src/Markdig.Tests/TestNormalize.cs
+++ b/src/Markdig.Tests/TestNormalize.cs
@@ -51,6 +51,16 @@ public class TestNormalize
        });
    }

+    [Test]
+    public void SyntaxHeadlineLevel7()
+    {
+        AssertSyntax("####### Headline", new HeadingBlock(null) {
+            HeaderChar = '#',
+            Level = 7,
+            Inline = new ContainerInline().AppendChild(new LiteralInline("Headline")),
+        });
+    }
+
    [Test]
    public void SyntaxParagraph()
    {
--- a/src/Markdig.Tests/TestPlayParser.cs
+++ b/src/Markdig.Tests/TestPlayParser.cs
@@ -9,6 +9,13 @@ namespace Markdig.Tests;
 [TestFixture]
 public class TestPlayParser
 {
+
+    [Test]
+    public void TestInvalidSetext()
+    {
+        TestParser.TestSpec("test\n===n", "<p>test\n===n</p>", "advanced");
+    }
+
    [Test]
    public void TestBugWithEmphasisAndTable()
    {
--- a/src/Markdig.Tests/TestSourcePosition.cs
+++ b/src/Markdig.Tests/TestSourcePosition.cs
@@ -698,14 +698,22 @@ literal      ( 0, 2)  2-3
    [Test]
    public void TestMathematicsInline()
    {
-        //     01 23456789AB
-        Check("0\n012 $abcd$", @"
-paragraph    ( 0, 0)  0-11
+        //     01 23456789ABCDEF
+        Check("0\n012 $abcd$ 321", @"
+paragraph    ( 0, 0)  0-15
 literal      ( 0, 0)  0-0
 linebreak    ( 0, 1)  1-1
 literal      ( 1, 0)  2-5
 math         ( 1, 4)  6-11
 attributes   ( 0, 0)  0--1
+literal      ( 1,10) 12-15
+", "mathematics");
+
+        //     012345678
+        Check("$ abcd $", @"
+paragraph    ( 0, 0)  0-7
+math         ( 0, 0)  0-7
+attributes   ( 0, 0)  0--1
 ", "mathematics");
    }

--- a/src/Markdig.WebApp/Markdig.WebApp.csproj
+++ b/src/Markdig.WebApp/Markdig.WebApp.csproj
@@ -1,7 +1,7 @@
 <Project Sdk="Microsoft.NET.Sdk.Web">

  <PropertyGroup>
-    <TargetFramework>net6.0</TargetFramework>
+    <TargetFramework>net8.0</TargetFramework>
    <PreserveCompilationContext>true</PreserveCompilationContext>
    <AssemblyName>Markdig.WebApp</AssemblyName>
    <ImplicitUsings>enable</ImplicitUsings>
--- a/src/Markdig/Extensions/Abbreviations/AbbreviationParser.cs
+++ b/src/Markdig/Extensions/Abbreviations/AbbreviationParser.cs
@@ -20,7 +20,7 @@ public class AbbreviationParser : BlockParser
    /// </summary>
    public AbbreviationParser()
    {
-        OpeningCharacters = new[] { '*' };
+        OpeningCharacters = ['*'];
    }

    public override BlockState TryOpen(BlockProcessor processor)
--- a/src/Markdig/Extensions/Alerts/AlertBlock.cs
+++ b/src/Markdig/Extensions/Alerts/AlertBlock.cs
@@ -0,0 +1,33 @@
+// Copyright (c) Alexandre Mutel. All rights reserved.
+// This file is licensed under the BSD-Clause 2 license.
+// See the license.txt file in the project root for more information.
+
+using Markdig.Helpers;
+using Markdig.Syntax;
+
+namespace Markdig.Extensions.Alerts;
+
+/// <summary>
+/// A block representing an alert quote block.
+/// </summary>
+public class AlertBlock : QuoteBlock
+{
+    /// <summary>
+    /// Creates a new instance of this block.
+    /// </summary>
+    /// <param name="kind"></param>
+    public AlertBlock(StringSlice kind) : base(null)
+    {
+        Kind = kind;
+    }
+
+    /// <summary>
+    /// Gets or sets the kind of the alert block (e.g `NOTE`, `TIP`, `IMPORTANT`, `WARNING`, `CAUTION`)
+    /// </summary>
+    public StringSlice Kind { get; set; }
+
+    /// <summary>
+    /// Gets or sets the trivia space after the kind.
+    /// </summary>
+    public StringSlice TriviaSpaceAfterKind { get; set; }
+}
--- a/src/Markdig/Extensions/Alerts/AlertBlockRenderer.cs
+++ b/src/Markdig/Extensions/Alerts/AlertBlockRenderer.cs
@@ -0,0 +1,87 @@
+// Copyright (c) Alexandre Mutel. All rights reserved.
+// This file is licensed under the BSD-Clause 2 license.
+// See the license.txt file in the project root for more information.
+
+using Markdig.Helpers;
+using Markdig.Renderers;
+using Markdig.Renderers.Html;
+using Markdig.Syntax;
+
+namespace Markdig.Extensions.Alerts;
+
+/// <summary>
+/// A HTML renderer for a <see cref="AlertBlock"/>.
+/// </summary>
+/// <seealso cref="HtmlObjectRenderer{AlertBlock}" />
+public class AlertBlockRenderer : HtmlObjectRenderer<AlertBlock>
+{
+    /// <summary>
+    /// Creates a new instance of this renderer.
+    /// </summary>
+    public AlertBlockRenderer()
+    {
+        RenderKind = DefaultRenderKind;
+    }
+
+    /// <summary>
+    /// Gets of sets a delegate to render the kind of the alert.
+    /// </summary>
+    public Action<HtmlRenderer, StringSlice> RenderKind { get; set; }
+
+
+    /// <inheritdoc />
+    protected override void Write(HtmlRenderer renderer, AlertBlock obj)
+    {
+        renderer.EnsureLine();
+        if (renderer.EnableHtmlForBlock)
+        {
+            renderer.Write("<div");
+            renderer.WriteAttributes(obj);
+            renderer.WriteLine('>');
+        }
+
+        RenderKind(renderer, obj.Kind);
+
+        var savedImplicitParagraph = renderer.ImplicitParagraph;
+        renderer.ImplicitParagraph = false;
+        renderer.WriteChildren(obj);
+        renderer.ImplicitParagraph = savedImplicitParagraph;
+        if (renderer.EnableHtmlForBlock)
+        {
+            renderer.WriteLine("</div>");
+        }
+
+        renderer.EnsureLine();
+    }
+
+
+    /// <summary>
+    /// Renders the kind of the alert.
+    /// </summary>
+    /// <param name="renderer">The HTML renderer.</param>
+    /// <param name="kind">The kind of the alert to render</param>
+    public static void DefaultRenderKind(HtmlRenderer renderer, StringSlice kind)
+    {
+        if (kind.Length >= 16)
+        {
+            return;
+        }
+
+        Span<char> upperKind = stackalloc char[kind.Length];
+        kind.AsSpan().ToUpperInvariant(upperKind);
+        string? html = upperKind switch
+        {
+            "NOTE" => "<p class=\"markdown-alert-title\"><svg viewBox=\"0 0 16 16\" version=\"1.1\" width=\"16\" height=\"16\" aria-hidden=\"true\"><path d=\"M0 8a8 8 0 1 1 16 0A8 8 0 0 1 0 8Zm8-6.5a6.5 6.5 0 1 0 0 13 6.5 6.5 0 0 0 0-13ZM6.5 7.75A.75.75 0 0 1 7.25 7h1a.75.75 0 0 1 .75.75v2.75h.25a.75.75 0 0 1 0 1.5h-2a.75.75 0 0 1 0-1.5h.25v-2h-.25a.75.75 0 0 1-.75-.75ZM8 6a1 1 0 1 1 0-2 1 1 0 0 1 0 2Z\"></path></svg>Note</p>",
+            "TIP" => "<p class=\"markdown-alert-title\"><svg viewBox=\"0 0 16 16\" version=\"1.1\" width=\"16\" height=\"16\" aria-hidden=\"true\"><path d=\"M8 1.5c-2.363 0-4 1.69-4 3.75 0 .984.424 1.625.984 2.304l.214.253c.223.264.47.556.673.848.284.411.537.896.621 1.49a.75.75 0 0 1-1.484.211c-.04-.282-.163-.547-.37-.847a8.456 8.456 0 0 0-.542-.68c-.084-.1-.173-.205-.268-.32C3.201 7.75 2.5 6.766 2.5 5.25 2.5 2.31 4.863 0 8 0s5.5 2.31 5.5 5.25c0 1.516-.701 2.5-1.328 3.259-.095.115-.184.22-.268.319-.207.245-.383.453-.541.681-.208.3-.33.565-.37.847a.751.751 0 0 1-1.485-.212c.084-.593.337-1.078.621-1.489.203-.292.45-.584.673-.848.075-.088.147-.173.213-.253.561-.679.985-1.32.985-2.304 0-2.06-1.637-3.75-4-3.75ZM5.75 12h4.5a.75.75 0 0 1 0 1.5h-4.5a.75.75 0 0 1 0-1.5ZM6 15.25a.75.75 0 0 1 .75-.75h2.5a.75.75 0 0 1 0 1.5h-2.5a.75.75 0 0 1-.75-.75Z\"></path></svg>Tip</p>",
+            "IMPORTANT" => "<p class=\"markdown-alert-title\"><svg viewBox=\"0 0 16 16\" version=\"1.1\" width=\"16\" height=\"16\" aria-hidden=\"true\"><path d=\"M0 1.75C0 .784.784 0 1.75 0h12.5C15.216 0 16 .784 16 1.75v9.5A1.75 1.75 0 0 1 14.25 13H8.06l-2.573 2.573A1.458 1.458 0 0 1 3 14.543V13H1.75A1.75 1.75 0 0 1 0 11.25Zm1.75-.25a.25.25 0 0 0-.25.25v9.5c0 .138.112.25.25.25h2a.75.75 0 0 1 .75.75v2.19l2.72-2.72a.749.749 0 0 1 .53-.22h6.5a.25.25 0 0 0 .25-.25v-9.5a.25.25 0 0 0-.25-.25Zm7 2.25v2.5a.75.75 0 0 1-1.5 0v-2.5a.75.75 0 0 1 1.5 0ZM9 9a1 1 0 1 1-2 0 1 1 0 0 1 2 0Z\"></path></svg>Important</p>",
+            "WARNING" => "<p class=\"markdown-alert-title\"><svg viewBox=\"0 0 16 16\" version=\"1.1\" width=\"16\" height=\"16\" aria-hidden=\"true\"><path d=\"M6.457 1.047c.659-1.234 2.427-1.234 3.086 0l6.082 11.378A1.75 1.75 0 0 1 14.082 15H1.918a1.75 1.75 0 0 1-1.543-2.575Zm1.763.707a.25.25 0 0 0-.44 0L1.698 13.132a.25.25 0 0 0 .22.368h12.164a.25.25 0 0 0 .22-.368Zm.53 3.996v2.5a.75.75 0 0 1-1.5 0v-2.5a.75.75 0 0 1 1.5 0ZM9 11a1 1 0 1 1-2 0 1 1 0 0 1 2 0Z\"></path></svg>Warning</p>",
+            "CAUTION" => "<p class=\"markdown-alert-title\"><svg viewBox=\"0 0 16 16\" version=\"1.1\" width=\"16\" height=\"16\" aria-hidden=\"true\"><path d=\"M4.47.22A.749.749 0 0 1 5 0h6c.199 0 .389.079.53.22l4.25 4.25c.141.14.22.331.22.53v6a.749.749 0 0 1-.22.53l-4.25 4.25A.749.749 0 0 1 11 16H5a.749.749 0 0 1-.53-.22L.22 11.53A.749.749 0 0 1 0 11V5c0-.199.079-.389.22-.53Zm.84 1.28L1.5 5.31v5.38l3.81 3.81h5.38l3.81-3.81V5.31L10.69 1.5ZM8 4a.75.75 0 0 1 .75.75v3.5a.75.75 0 0 1-1.5 0v-3.5A.75.75 0 0 1 8 4Zm0 8a1 1 0 1 1 0-2 1 1 0 0 1 0 2Z\"></path></svg>Caution</p>",
+            _ => null
+        };
+
+        if (html is not null)
+        {
+            renderer.WriteLine(html);
+        }
+    }
+}
--- a/src/Markdig/Extensions/Alerts/AlertExtension.cs
+++ b/src/Markdig/Extensions/Alerts/AlertExtension.cs
@@ -0,0 +1,44 @@
+// Copyright (c) Alexandre Mutel. All rights reserved.
+// This file is licensed under the BSD-Clause 2 license.
+// See the license.txt file in the project root for more information.
+
+using Markdig.Helpers;
+using Markdig.Parsers.Inlines;
+using Markdig.Renderers;
+using Markdig.Renderers.Html;
+
+namespace Markdig.Extensions.Alerts;
+
+/// <summary>
+/// Extension for adding alerts to a Markdown pipeline.
+/// </summary>
+public class AlertExtension : IMarkdownExtension
+{
+    /// <summary>
+    /// Gets or sets the delegate to render the kind of the alert.
+    /// </summary>
+    public Action<HtmlRenderer, StringSlice>? RenderKind { get; set; }
+
+    /// <inheritdoc />
+    public void Setup(MarkdownPipelineBuilder pipeline)
+    {
+        var inlineParser = pipeline.InlineParsers.Find<AlertInlineParser>();
+        if (inlineParser == null)
+        {
+            pipeline.InlineParsers.InsertBefore<LinkInlineParser>(new AlertInlineParser());
+        }
+    }
+
+    /// <inheritdoc />
+    public void Setup(MarkdownPipeline pipeline, IMarkdownRenderer renderer)
+    {
+        var blockRenderer = renderer.ObjectRenderers.FindExact<AlertBlockRenderer>();
+        if (blockRenderer == null)
+        {
+            renderer.ObjectRenderers.InsertBefore<QuoteBlockRenderer>(new AlertBlockRenderer()
+            {
+                RenderKind = RenderKind ?? AlertBlockRenderer.DefaultRenderKind
+            });
+        }
+    }
+}
--- a/src/Markdig/Extensions/Alerts/AlertInlineParser.cs
+++ b/src/Markdig/Extensions/Alerts/AlertInlineParser.cs
@@ -0,0 +1,127 @@
+// Copyright (c) Alexandre Mutel. All rights reserved.
+// This file is licensed under the BSD-Clause 2 license.
+// See the license.txt file in the project root for more information.
+
+using Markdig.Helpers;
+using Markdig.Parsers;
+using Markdig.Renderers.Html;
+using Markdig.Syntax;
+using Markdig.Syntax.Inlines;
+
+namespace Markdig.Extensions.Alerts;
+
+/// <summary>
+/// An inline parser for an alert inline (e.g. `[!NOTE]`).
+/// </summary>
+/// <seealso cref="InlineParser" />
+public class AlertInlineParser : InlineParser
+{
+    /// <summary>
+    /// Initializes a new instance of the <see cref="AlertInlineParser"/> class.
+    /// </summary>
+    public AlertInlineParser()
+    {
+        OpeningCharacters = ['['];
+    }
+
+    public override bool Match(InlineProcessor processor, ref StringSlice slice)
+    {
+        // We expect the alert to be the first child of a quote block. Example:
+        // > [!NOTE]
+        // > This is a note
+        if (processor.Block is not ParagraphBlock paragraphBlock || paragraphBlock.Parent is not QuoteBlock quoteBlock || paragraphBlock.Inline?.FirstChild != null)
+        {
+            return false;
+        }
+
+        var saved = slice;
+        var c = slice.NextChar();
+        if (c != '!')
+        {
+            slice = saved;
+            return false;
+        }
+
+        c = slice.NextChar(); // Skip !
+
+        var start = slice.Start;
+        var end = start;
+        while (c.IsAlpha())
+        {
+            end = slice.Start;
+            c = slice.NextChar();
+        }
+
+        // We need at least one character
+        if (c != ']' || start == end)
+        {
+            slice = saved;
+            return false;
+        }
+
+        var alertType = new StringSlice(slice.Text, start, end);
+        c = slice.NextChar(); // Skip ]
+
+        start = slice.Start;
+        while (true)
+        {
+            if (c == '\0' || c == '\n' || c == '\r')
+            {
+                end = slice.Start;
+                if (c == '\r')
+                {
+                    c = slice.NextChar(); // Skip \r
+                    if (c == '\0' || c == '\n')
+                    {
+                        end = slice.Start;
+                        if (c == '\n')
+                        {
+                            slice.NextChar(); // Skip \n
+                        }
+                    }
+                }
+                else if (c == '\n')
+                {
+                    slice.NextChar(); // Skip \n
+                }
+                break;
+            }
+            else if (!c.IsSpaceOrTab())
+            {
+                slice = saved;
+                return false;
+            }
+
+            c = slice.NextChar();
+        }
+
+        var alertBlock = new AlertBlock(alertType)
+        {
+            Span = quoteBlock.Span,
+            TriviaSpaceAfterKind = new StringSlice(slice.Text, start, end),
+            Line = quoteBlock.Line,
+            Column = quoteBlock.Column,
+        };
+
+        alertBlock.GetAttributes().AddClass("markdown-alert");
+        alertBlock.GetAttributes().AddClass($"markdown-alert-{alertType.ToString().ToLowerInvariant()}");
+
+        // Replace the quote block with the alert block
+        var parentQuoteBlock = quoteBlock.Parent!;
+        var indexOfQuoteBlock = parentQuoteBlock.IndexOf(quoteBlock);
+        parentQuoteBlock[indexOfQuoteBlock] = alertBlock;
+
+        while (quoteBlock.Count > 0)
+        {
+            var block = quoteBlock[0];
+            quoteBlock.RemoveAt(0);
+            alertBlock.Add(block);
+        }
+
+        // Workaround to replace the parent container
+        // Experimental API, so we are keeping it internal for now until we are sure it's the way we want to go
+        processor.ReplaceParentContainer(quoteBlock, alertBlock);
+
+        return true;
+    }
+}
--- a/src/Markdig/Extensions/AutoIdentifiers/AutoIdentifierExtension.cs
+++ b/src/Markdig/Extensions/AutoIdentifiers/AutoIdentifierExtension.cs
@@ -2,8 +2,6 @@
 // This file is licensed under the BSD-Clause 2 license.
 // See the license.txt file in the project root for more information.

-using System.IO;
-
 using Markdig.Helpers;
 using Markdig.Parsers;
 using Markdig.Renderers;
--- a/src/Markdig/Extensions/AutoLinks/AutoLinkExtension.cs
+++ b/src/Markdig/Extensions/AutoLinks/AutoLinkExtension.cs
@@ -11,14 +11,9 @@ namespace Markdig.Extensions.AutoLinks;
 /// Extension to automatically create <see cref="LinkInline"/> when a link url http: or mailto: is found.
 /// </summary>
 /// <seealso cref="IMarkdownExtension" />
-public class AutoLinkExtension : IMarkdownExtension
+public class AutoLinkExtension(AutoLinkOptions? options) : IMarkdownExtension
 {
-    public readonly AutoLinkOptions Options;
-
-    public AutoLinkExtension(AutoLinkOptions? options)
-    {
-        Options = options ?? new AutoLinkOptions();
-    }
+    public readonly AutoLinkOptions Options = options ?? new AutoLinkOptions();

    public void Setup(MarkdownPipelineBuilder pipeline)
    {
--- a/src/Markdig/Extensions/AutoLinks/AutoLinkParser.cs
+++ b/src/Markdig/Extensions/AutoLinks/AutoLinkParser.cs
@@ -22,14 +22,14 @@ public class AutoLinkParser : InlineParser
    {
        Options = options ?? throw new ArgumentNullException(nameof(options));

-        OpeningCharacters = new char[]
-        {
+        OpeningCharacters =
+        [
            'h', // for http:// and https://
            'f', // for ftp://
            'm', // for mailto:
            't', // for tel:
            'w', // for www.
-        };
+        ];

        _listOfCharCache = new ListOfCharCache();
    }
--- a/src/Markdig/Extensions/Bootstrap/BootstrapExtension.cs
+++ b/src/Markdig/Extensions/Bootstrap/BootstrapExtension.cs
@@ -1,7 +1,9 @@
 // Copyright (c) Alexandre Mutel. All rights reserved.
-// This file is licensed under the BSD-Clause 2 license. 
+// This file is licensed under the BSD-Clause 2 license.
 // See the license.txt file in the project root for more information.

+using System.Linq;
+using Markdig.Extensions.Alerts;
 using Markdig.Renderers;
 using Markdig.Renderers.Html;
 using Markdig.Syntax;
@@ -24,10 +26,22 @@ public class BootstrapExtension : IMarkdownExtension

    public void Setup(MarkdownPipeline pipeline, IMarkdownRenderer renderer)
    {
+        if (renderer is HtmlRenderer htmlRenderer)
+        {
+            var alertRenderer = htmlRenderer.ObjectRenderers.OfType<AlertBlockRenderer>().FirstOrDefault();
+            if (alertRenderer == null)
+            {
+                alertRenderer = new AlertBlockRenderer();
+                renderer.ObjectRenderers.InsertBefore<QuoteBlockRenderer>(new AlertBlockRenderer());
+            }
+
+            alertRenderer.RenderKind = (_, _) => { };
+        }
    }

    private static void PipelineOnDocumentProcessed(MarkdownDocument document)
    {
+        Span<char> upperKind = new char[16];
        foreach (var node in document.Descendants())
        {
            if (node.IsInline)
@@ -43,6 +57,28 @@ public class BootstrapExtension : IMarkdownExtension
                {
                    node.GetAttributes().AddClass("table");
                }
+                else if (node is AlertBlock alertBlock) // Needs to be before QuoteBlock
+                {
+                    var attributes = node.GetAttributes();
+                    attributes.AddClass("alert");
+                    attributes.AddProperty("role", "alert");
+                    if (alertBlock.Kind.Length <= upperKind.Length)
+                    {
+                        alertBlock.Kind.AsSpan().ToUpperInvariant(upperKind);
+                        attributes.AddClass(upperKind.Slice(0, alertBlock.Kind.Length) switch
+                        {
+                            "NOTE" => "alert-primary",
+                            "TIP" => "alert-success",
+                            "IMPORTANT" => "alert-info",
+                            "WARNING" => "alert-warning",
+                            "CAUTION" => "alert-danger",
+                            _ => "alert-dark",
+                        });
+                    }
+
+                    var lastParagraph = alertBlock.Descendants().OfType<ParagraphBlock>().LastOrDefault();
+                    lastParagraph?.GetAttributes().AddClass("mb-0");
+                }
                else if (node is QuoteBlock)
                {
                    node.GetAttributes().AddClass("blockquote");
--- a/src/Markdig/Extensions/CustomContainers/CustomContainerParser.cs
+++ b/src/Markdig/Extensions/CustomContainers/CustomContainerParser.cs
@@ -17,7 +17,7 @@ public class CustomContainerParser : FencedBlockParserBase<CustomContainer>
    /// </summary>
    public CustomContainerParser()
    {
-        OpeningCharacters = new [] {':'};
+        OpeningCharacters = [':'];

        // We don't need a prefix
        InfoPrefix = null;
--- a/src/Markdig/Extensions/DefinitionLists/DefinitionListParser.cs
+++ b/src/Markdig/Extensions/DefinitionLists/DefinitionListParser.cs
@@ -18,7 +18,7 @@ public class DefinitionListParser : BlockParser
    /// </summary>
    public DefinitionListParser()
    {
-        OpeningCharacters = new [] {':', '~'};
+        OpeningCharacters = [':', '~'];
    }

    public override BlockState TryOpen(BlockProcessor processor)
--- a/src/Markdig/Extensions/Diagrams/DiagramExtension.cs
+++ b/src/Markdig/Extensions/Diagrams/DiagramExtension.cs
@@ -1,5 +1,5 @@
 // Copyright (c) Alexandre Mutel. All rights reserved.
-// This file is licensed under the BSD-Clause 2 license. 
+// This file is licensed under the BSD-Clause 2 license.
 // See the license.txt file in the project root for more information.

 using Markdig.Renderers;
@@ -22,9 +22,8 @@ public class DiagramExtension : IMarkdownExtension
        if (renderer is HtmlRenderer htmlRenderer)
        {
            var codeRenderer = htmlRenderer.ObjectRenderers.FindExact<CodeBlockRenderer>()!;
-            // TODO: Add other well known diagram languages
-            codeRenderer.BlocksAsDiv.Add("mermaid");
+            codeRenderer.BlockMapping["mermaid"] = "pre";
            codeRenderer.BlocksAsDiv.Add("nomnoml");
        }
    }
-}
+}
--- a/src/Markdig/Extensions/Emoji/EmojiMapping.cs
+++ b/src/Markdig/Extensions/Emoji/EmojiMapping.cs
@@ -1786,6 +1786,6 @@ public class EmojiMapping
                ThrowHelper.ArgumentException(string.Format("Smiley {0} is already present in the emoji mapping", smiley.Key));
        }

-        OpeningCharacters = new List<char>(firstChars).ToArray();
+        OpeningCharacters = [.. firstChars];
    }
 }
--- a/src/Markdig/Extensions/Figures/FigureBlockParser.cs
+++ b/src/Markdig/Extensions/Figures/FigureBlockParser.cs
@@ -18,7 +18,7 @@ public class FigureBlockParser : BlockParser
    /// </summary>
    public FigureBlockParser()
    {
-        OpeningCharacters = new[] { '^' };
+        OpeningCharacters = ['^'];
    }

    public override BlockState TryOpen(BlockProcessor processor)
--- a/src/Markdig/Extensions/Footers/FooterBlockParser.cs
+++ b/src/Markdig/Extensions/Footers/FooterBlockParser.cs
@@ -19,7 +19,7 @@ public class FooterBlockParser : BlockParser
    /// </summary>
    public FooterBlockParser()
    {
-        OpeningCharacters = new[] {'^'};
+        OpeningCharacters = ['^'];
    }

    public override BlockState TryOpen(BlockProcessor processor)
--- a/src/Markdig/Extensions/Footnotes/FootnoteParser.cs
+++ b/src/Markdig/Extensions/Footnotes/FootnoteParser.cs
@@ -22,7 +22,7 @@ public class FootnoteParser : BlockParser

    public FootnoteParser()
    {
-        OpeningCharacters = new [] {'['};
+        OpeningCharacters = ['['];
    }

    public override BlockState TryOpen(BlockProcessor processor)
@@ -49,7 +49,7 @@ public class FootnoteParser : BlockParser

        // Advance the column
        int deltaColumn = processor.Start - start;
-        processor.Column = processor.Column + deltaColumn;
+        processor.Column += deltaColumn;

        processor.NextChar(); // Skip ':'

@@ -170,10 +170,8 @@ public class FootnoteParser : BlockParser
                paragraphBlock = new ParagraphBlock();
                footnote.Add(paragraphBlock);
            }
-            if (paragraphBlock.Inline == null)
-            {
-                paragraphBlock.Inline = new ContainerInline();
-            }
+
+            paragraphBlock.Inline ??= new ContainerInline();

            foreach (var link in footnote.Links)
            {
--- a/src/Markdig/Extensions/GenericAttributes/GenericAttributesParser.cs
+++ b/src/Markdig/Extensions/GenericAttributes/GenericAttributesParser.cs
@@ -23,7 +23,7 @@ public class GenericAttributesParser : InlineParser
    /// </summary>
    public GenericAttributesParser()
    {
-        OpeningCharacters = new[] { '{' };
+        OpeningCharacters = ['{'];
    }

    public override bool Match(InlineProcessor processor, ref StringSlice slice)
@@ -136,10 +136,7 @@ public class GenericAttributesParser : InlineParser
                var text = slice.Text.Substring(start, end - start + 1);
                if (isClass)
                {
-                    if (classes is null)
-                    {
-                        classes = new List<string>();
-                    }
+                    classes ??= new List<string>();
                    classes.Add(text);
                }
                else
--- a/src/Markdig/Extensions/Mathematics/MathBlockParser.cs
+++ b/src/Markdig/Extensions/Mathematics/MathBlockParser.cs
@@ -20,7 +20,7 @@ public class MathBlockParser : FencedBlockParserBase<MathBlock>
    /// </summary>
    public MathBlockParser()
    {
-        OpeningCharacters = new [] {'$'};
+        OpeningCharacters = ['$'];
        // We expect to match only a $$, no less, no more
        MinimumMatchCount = 2;
        MaximumMatchCount = 2;
--- a/src/Markdig/Extensions/Mathematics/MathInlineParser.cs
+++ b/src/Markdig/Extensions/Mathematics/MathInlineParser.cs
@@ -21,7 +21,7 @@ public class MathInlineParser : InlineParser
    /// </summary>
    public MathInlineParser()
    {
-        OpeningCharacters = new[] { '$' };
+        OpeningCharacters = ['$'];
        DefaultClass = "math";
    }

@@ -152,7 +152,7 @@ public class MathInlineParser : InlineParser
            // Create a new MathInline
            var inline = new MathInline()
            {
-                Span = new SourceSpan(processor.GetSourcePosition(startPosition, out int line, out int column), processor.GetSourcePosition(slice.End)),
+                Span = new SourceSpan(processor.GetSourcePosition(startPosition, out int line, out int column), processor.GetSourcePosition(slice.Start - 1)),
                Line = line,
                Column = column,
                Delimiter = match,
--- a/src/Markdig/Extensions/MediaLinks/HostProviderBuilder.cs
+++ b/src/Markdig/Extensions/MediaLinks/HostProviderBuilder.cs
@@ -11,23 +11,19 @@ namespace Markdig.Extensions.MediaLinks;

 public class HostProviderBuilder
 {
-    private sealed class DelegateProvider : IHostProvider
+    private sealed class DelegateProvider(
+        string hostPrefix,
+        Func<Uri, string?> handler,
+        bool allowFullscreen = true,
+        string? className = null) : IHostProvider
    {
-        public DelegateProvider(string hostPrefix, Func<Uri, string?> handler, bool allowFullscreen = true, string? className = null)
-        {
-            HostPrefix = hostPrefix;
-            Delegate = handler;
-            AllowFullScreen = allowFullscreen;
-            Class = className;
-        }
+        public string HostPrefix { get; } = hostPrefix;

-        public string HostPrefix { get; }
+        public Func<Uri, string?> Delegate { get; } = handler;

-        public Func<Uri, string?> Delegate { get; }
+        public bool AllowFullScreen { get; } = allowFullscreen;

-        public bool AllowFullScreen { get; }
-
-        public string? Class { get; }
+        public string? Class { get; } = className;

        public bool TryHandle(Uri mediaUri, bool isSchemaRelative, [NotNullWhen(true)] out string? iframeUrl)
        {
@@ -62,6 +58,7 @@ public class HostProviderBuilder
    internal static Dictionary<string, IHostProvider> KnownHosts { get; }
        = new Dictionary<string, IHostProvider>(StringComparer.OrdinalIgnoreCase)
        {
+            ["YouTubeShort"] = Create("www.youtube.com", YouTubeShort, iframeClass: "youtubeshort"),
            ["YouTube"] = Create("www.youtube.com", YouTube, iframeClass: "youtube"),
            ["YouTubeShortened"] = Create("youtu.be", YouTubeShortened, iframeClass: "youtube"),
            ["Vimeo"] = Create("vimeo.com", Vimeo, iframeClass: "vimeo"),
@@ -71,7 +68,7 @@ public class HostProviderBuilder

    #region Known providers

-    private static readonly string[] SplitAnd = { "&" };
+    private static readonly string[] SplitAnd = ["&"];
    private static string[] SplitQuery(Uri uri)
    {
        var query = uri.Query.Substring(uri.Query.IndexOf('?') + 1);
@@ -96,6 +93,19 @@ public class HostProviderBuilder
        );
    }

+    private static string? YouTubeShort(Uri uri)
+    {
+        string uriPath = uri.AbsolutePath;
+        bool isYouTubeShort = uriPath.StartsWith("/shorts/", StringComparison.OrdinalIgnoreCase);
+        if (!isYouTubeShort)
+        {
+            return null;
+        }
+
+        var shortId = uriPath.Substring("/shorts/".Length).Split('?').FirstOrDefault(); // the format might be "/shorts/6BUptHVuvyI?feature=share"
+        return BuildYouTubeIframeUrl(shortId, null);
+    }
+
    private static string? YouTubeShortened(Uri uri)
    {
        return BuildYouTubeIframeUrl(
--- a/src/Markdig/Extensions/NoRefLinks/NoFollowLinksExtension.cs
+++ b/src/Markdig/Extensions/NoRefLinks/NoFollowLinksExtension.cs
@@ -17,7 +17,7 @@ public class NoFollowLinksExtension : IMarkdownExtension

    public NoFollowLinksExtension()
    {
-        _referralLinksExtension = new ReferralLinksExtension(new[] { "nofollow" });
+        _referralLinksExtension = new ReferralLinksExtension(["nofollow"]);
    }

    public void Setup(MarkdownPipelineBuilder pipeline)
--- a/src/Markdig/Extensions/SmartyPants/SmartyPantsInlineParser.cs
+++ b/src/Markdig/Extensions/SmartyPants/SmartyPantsInlineParser.cs
@@ -19,7 +19,7 @@ public class SmartyPantsInlineParser : InlineParser, IPostInlineProcessor
    /// </summary>
    public SmartyPantsInlineParser()
    {
-        OpeningCharacters = new[] {'\'', '"', '<', '>', '.', '-'};
+        OpeningCharacters = ['\'', '"', '<', '>', '.', '-'];
    }

    public override bool Match(InlineProcessor processor, ref StringSlice slice)
--- a/src/Markdig/Extensions/Tables/GridTableParser.cs
+++ b/src/Markdig/Extensions/Tables/GridTableParser.cs
@@ -12,7 +12,7 @@ public class GridTableParser : BlockParser
 {
    public GridTableParser()
    {
-        OpeningCharacters = new[] { '+' };
+        OpeningCharacters = ['+'];
    }

    public override BlockState TryOpen(BlockProcessor processor)
@@ -144,7 +144,7 @@ public class GridTableParser : BlockParser
                line.Start = lineStart + columnSlice.Start + 1;
                line.End = lineStart + columnSlice.End - 1;
                line.Trim();
-                if (line.IsEmptyOrWhitespace() || !IsRowSeperator(line))
+                if (line.IsEmptyOrWhitespace() || !IsRowSeparator(line))
                {
                    hasRowSpan = true;
                    columnSlice.CurrentCell.RowSpan++;
@@ -158,7 +158,7 @@ public class GridTableParser : BlockParser
        }
    }

-    private static bool IsRowSeperator(StringSlice slice)
+    private static bool IsRowSeparator(StringSlice slice)
    {
        char c = slice.CurrentChar;
        do
@@ -263,7 +263,7 @@ public class GridTableParser : BlockParser
            }
            sliceForCell.TrimEnd();

-            if (!isRowLine || !IsRowSeperator(sliceForCell))
+            if (!isRowLine || !IsRowSeparator(sliceForCell))
            {
                if (columnSlice.CurrentCell is null)
                {
@@ -273,10 +273,7 @@ public class GridTableParser : BlockParser
                        ColumnIndex = i
                    };

-                    if (columnSlice.BlockProcessor is null)
-                    {
-                        columnSlice.BlockProcessor = processor.CreateChild();
-                    }
+                    columnSlice.BlockProcessor ??= processor.CreateChild();

                    // Ensure that the BlockParser is aware that the TableCell is the top-level container
                    columnSlice.BlockProcessor.Open(columnSlice.CurrentCell);
--- a/src/Markdig/Extensions/Tables/GridTableState.cs
+++ b/src/Markdig/Extensions/Tables/GridTableState.cs
@@ -10,21 +10,15 @@ namespace Markdig.Extensions.Tables;
 /// <summary>
 /// Internal state used by the <see cref="GridTableParser"/>
 /// </summary>
-internal sealed class GridTableState
+internal sealed class GridTableState(int start, bool expectRow)
 {
-    public GridTableState(int start, bool expectRow)
-    {
-        Start = start;
-        ExpectRow = expectRow;
-    }
-
-    public int Start { get; }
+    public int Start { get; } = start;

    public StringLineGroup Lines;

    public List<ColumnSlice>? ColumnSlices { get; private set; }

-    public bool ExpectRow { get; }
+    public bool ExpectRow { get; } = expectRow;

    public int StartRowGroup { get; set; }

@@ -45,26 +39,18 @@ internal sealed class GridTableState
        ColumnSlices.Add(new ColumnSlice(start, end, align));
    }

-    public sealed class ColumnSlice
+    public sealed class ColumnSlice(int start, int end, TableColumnAlign? align)
    {
-        public ColumnSlice(int start, int end, TableColumnAlign? align)
-        {
-            Start = start;
-            End = end;
-            Align = align;
-            CurrentColumnSpan = -1;
-        }
-
        /// <summary>
        /// Gets or sets the index position of this column (after the |)
        /// </summary>
-        public int Start { get; }
+        public int Start { get; } = start;

-        public int End { get; }
+        public int End { get; } = end;

-        public TableColumnAlign? Align { get; }
+        public TableColumnAlign? Align { get; } = align;

-        public int CurrentColumnSpan { get; set; }
+        public int CurrentColumnSpan { get; set; } = -1;

        public int PreviousColumnSpan { get; set; }

--- a/src/Markdig/Extensions/Tables/PipeTableBlockParser.cs
+++ b/src/Markdig/Extensions/Tables/PipeTableBlockParser.cs
@@ -22,7 +22,7 @@ public class PipeTableBlockParser : BlockParser
    /// </summary>
    public PipeTableBlockParser()
    {
-        OpeningCharacters = new[] {'-'};
+        OpeningCharacters = ['-'];
    }

    public override BlockState TryOpen(BlockProcessor processor)
--- a/src/Markdig/Extensions/Tables/PipeTableParser.cs
+++ b/src/Markdig/Extensions/Tables/PipeTableParser.cs
@@ -25,12 +25,12 @@ public class PipeTableParser : InlineParser, IPostInlineProcessor
    /// <summary>
    /// Initializes a new instance of the <see cref="PipeTableParser" /> class.
    /// </summary>
-    /// <param name="lineBreakParser">The linebreak parser to use</param>
+    /// <param name="lineBreakParser">The line break parser to use</param>
    /// <param name="options">The options.</param>
    public PipeTableParser(LineBreakInlineParser lineBreakParser, PipeTableOptions? options = null)
    {
        this.lineBreakParser = lineBreakParser ?? throw new ArgumentNullException(nameof(lineBreakParser));
-        OpeningCharacters = new[] { '|', '\n', '\r' };
+        OpeningCharacters = ['|', '\n', '\r'];
        Options = options ?? new PipeTableOptions();
    }

@@ -637,10 +637,10 @@ public class PipeTableParser : InlineParser, IPostInlineProcessor

        public int LineIndex { get; set; }

-        public List<Inline> ColumnAndLineDelimiters { get; } = new();
+        public List<Inline> ColumnAndLineDelimiters { get; } = [];

-        public List<TableCell> Cells { get; } = new();
+        public List<TableCell> Cells { get; } = [];

-        public List<Inline> EndOfLines { get; } = new();
+        public List<Inline> EndOfLines { get; } = [];
    }
 }
--- a/src/Markdig/Extensions/TaskLists/TaskListInlineParser.cs
+++ b/src/Markdig/Extensions/TaskLists/TaskListInlineParser.cs
@@ -19,7 +19,7 @@ public class TaskListInlineParser : InlineParser
    /// </summary>
    public TaskListInlineParser()
    {
-        OpeningCharacters = new[] {'['};
+        OpeningCharacters = ['['];
        ListClass = "contains-task-list";
        ListItemClass = "task-list-item";
    }
--- a/src/Markdig/Extensions/Yaml/YamlFrontMatterParser.cs
+++ b/src/Markdig/Extensions/Yaml/YamlFrontMatterParser.cs
@@ -26,7 +26,7 @@ public class YamlFrontMatterParser : BlockParser
    /// </summary>
    public YamlFrontMatterParser()
    {
-        this.OpeningCharacters = new[] { '-' };
+        OpeningCharacters = ['-'];
    }

    /// <summary>
--- a/src/Markdig/Helpers/BlockWrapper.cs
+++ b/src/Markdig/Helpers/BlockWrapper.cs
@@ -7,14 +7,9 @@ using Markdig.Syntax;
 namespace Markdig.Helpers;

 // Used to avoid the overhead of type covariance checks
-internal readonly struct BlockWrapper : IEquatable<BlockWrapper>
+internal readonly struct BlockWrapper(Block block) : IEquatable<BlockWrapper>
 {
-    public readonly Block Block;
-
-    public BlockWrapper(Block block)
-    {
-        Block = block;
-    }
+    public readonly Block Block = block;

    public static implicit operator Block(BlockWrapper wrapper) => wrapper.Block;

--- a/src/Markdig/Helpers/CharHelper.cs
+++ b/src/Markdig/Helpers/CharHelper.cs
@@ -722,11 +722,11 @@ public static class CharHelper
    }

    // Used by ListExtraItemParser to format numbers from 1 - 26
-    private static readonly string[] smallNumberStringCache = {
+    private static readonly string[] smallNumberStringCache = [
        "0", "1", "2", "3", "4", "5", "6", "7", "8", "9",
        "10", "11", "12", "13", "14", "15", "16", "17", "18", "19",
        "20", "21", "22", "23", "24", "25", "26",
-    };
+    ];

    internal static string SmallNumberToString(int number)
    {
--- a/src/Markdig/Helpers/CharacterMap.cs
+++ b/src/Markdig/Helpers/CharacterMap.cs
@@ -35,7 +35,7 @@ public sealed class CharacterMap<T> where T : class
            charSet.Add(map.Key);
        }

-        OpeningCharacters = charSet.ToArray();
+        OpeningCharacters = [.. charSet];
        Array.Sort(OpeningCharacters);

        _asciiMap = new T[128];
--- a/src/Markdig/Helpers/HtmlHelper.cs
+++ b/src/Markdig/Helpers/HtmlHelper.cs
@@ -12,8 +12,8 @@ namespace Markdig.Helpers;
 /// </summary>
 public static class HtmlHelper
 {
-    private static readonly char[] SearchBackAndAmp = { '\\', '&' };
-    private static readonly char[] SearchAmp = { '&' };
+    private static readonly char[] SearchBackAndAmp = ['\\', '&'];
+    private static readonly char[] SearchAmp = ['&'];
    private static readonly string[] EscapeUrlsForAscii = new string[128];

    static HtmlHelper()
--- a/src/Markdig/Helpers/StringLineGroup.cs
+++ b/src/Markdig/Helpers/StringLineGroup.cs
@@ -187,16 +187,10 @@ public struct StringLineGroup : IEnumerable
        }
    }

-    public struct Enumerator : IEnumerator
+    public struct Enumerator(StringLineGroup parent) : IEnumerator
    {
-        private readonly StringLineGroup _parent;
-        private int _index;
-
-        public Enumerator(StringLineGroup parent)
-        {
-            _parent = parent;
-            _index = -1;
-        }
+        private readonly StringLineGroup _parent = parent;
+        private int _index = -1;

        public object Current => _parent.Lines[_index];

@@ -452,25 +446,21 @@ public struct StringLineGroup : IEnumerable
        }
    }

-    public readonly struct LineOffset
+    public readonly struct LineOffset(
+        int linePosition,
+        int column,
+        int offset,
+        int start,
+        int end)
    {
-        public LineOffset(int linePosition, int column, int offset, int start, int end)
-        {
-            LinePosition = linePosition;
-            Column = column;
-            Offset = offset;
-            Start = start;
-            End = end;
-        }
+        public readonly int LinePosition = linePosition;

-        public readonly int LinePosition;
+        public readonly int Column = column;

-        public readonly int Column;
+        public readonly int Offset = offset;

-        public readonly int Offset;
+        public readonly int Start = start;

-        public readonly int Start;
-
-        public readonly int End;
+        public readonly int End = end;
    }
 }
--- a/src/Markdig/MarkdownExtensions.cs
+++ b/src/Markdig/MarkdownExtensions.cs
@@ -3,6 +3,7 @@
 // See the license.txt file in the project root for more information.

 using Markdig.Extensions.Abbreviations;
+using Markdig.Extensions.Alerts;
 using Markdig.Extensions.AutoIdentifiers;
 using Markdig.Extensions.AutoLinks;
 using Markdig.Extensions.Bootstrap;
@@ -34,6 +35,7 @@ using Markdig.Extensions.Yaml;
 using Markdig.Helpers;
 using Markdig.Parsers;
 using Markdig.Parsers.Inlines;
+using Markdig.Renderers;

 namespace Markdig;

@@ -74,6 +76,7 @@ public static class MarkdownExtensions
    public static MarkdownPipelineBuilder UseAdvancedExtensions(this MarkdownPipelineBuilder pipeline)
    {
        return pipeline
+            .UseAlertBlocks()
            .UseAbbreviations()
            .UseAutoIdentifiers()
            .UseCitations()
@@ -94,6 +97,18 @@ public static class MarkdownExtensions
            .UseGenericAttributes(); // Must be last as it is one parser that is modifying other parsers
    }

+    /// <summary>
+    /// Uses this extension to enable alert blocks.
+    /// </summary>
+    /// <param name="pipeline">The pipeline.</param>
+    /// <param name="renderKind">Replace the default renderer for the kind with a custom renderer</param>
+    /// <returns>The modified pipeline</returns>
+    public static MarkdownPipelineBuilder UseAlertBlocks(this MarkdownPipelineBuilder pipeline, Action<HtmlRenderer, StringSlice>? renderKind = null)
+    {
+        pipeline.Extensions.ReplaceOrAdd<AlertExtension>(new AlertExtension() { RenderKind = renderKind });
+        return pipeline;
+    }
+    
    /// <summary>
    /// Uses this extension to enable autolinks from text `http://`, `https://`, `ftp://`, `mailto:`, `www.xxx.yyy`
    /// </summary>
@@ -552,6 +567,9 @@ public static class MarkdownExtensions
                case "advanced":
                    pipeline.UseAdvancedExtensions();
                    break;
+                case "alerts":
+                    pipeline.UseAlertBlocks();
+                    break;
                case "pipetables":
                    pipeline.UsePipeTables();
                    break;
--- a/src/Markdig/MarkdownPipeline.cs
+++ b/src/Markdig/MarkdownPipeline.cs
@@ -95,18 +95,14 @@ public sealed class MarkdownPipeline
        return new RentedHtmlRenderer(cache, renderer);
    }

-    internal sealed class HtmlRendererCache : ObjectCache<HtmlRenderer>
+    internal sealed class HtmlRendererCache(
+        MarkdownPipeline pipeline,
+        bool customWriter = false) : ObjectCache<HtmlRenderer>
    {
-        private static readonly TextWriter s_dummyWriter = new FastStringWriter();
+        private static readonly FastStringWriter s_dummyWriter = new();

-        private readonly MarkdownPipeline _pipeline;
-        private readonly bool _customWriter;
-
-        public HtmlRendererCache(MarkdownPipeline pipeline, bool customWriter = false)
-        {
-            _pipeline = pipeline;
-            _customWriter = customWriter;
-        }
+        private readonly MarkdownPipeline _pipeline = pipeline;
+        private readonly bool _customWriter = customWriter;

        protected override HtmlRenderer NewInstance()
        {
--- a/src/Markdig/MarkdownPipelineBuilder.cs
+++ b/src/Markdig/MarkdownPipelineBuilder.cs
@@ -24,8 +24,8 @@ public class MarkdownPipelineBuilder
    public MarkdownPipelineBuilder()
    {
        // Add all default parsers
-        BlockParsers = new OrderedList<BlockParser>()
-        {
+        BlockParsers =
+        [
            new ThematicBreakParser(),
            new HeadingBlockParser(),
            new QuoteBlockParser(),
@@ -35,10 +35,10 @@ public class MarkdownPipelineBuilder
            new FencedCodeBlockParser(),
            new IndentedCodeBlockParser(),
            new ParagraphBlockParser(),
-        };
+        ];

-        InlineParsers = new OrderedList<InlineParser>()
-        {
+        InlineParsers =
+        [
            new HtmlEntityParser(),
            new LinkInlineParser(),
            new EscapeInlineParser(),
@@ -46,7 +46,7 @@ public class MarkdownPipelineBuilder
            new CodeInlineParser(),
            new AutolinkInlineParser(),
            new LineBreakInlineParser(),
-        };
+        ];

        Extensions = new OrderedList<IMarkdownExtension>();
    }
--- a/src/Markdig/Parsers/BlockProcessor.cs
+++ b/src/Markdig/Parsers/BlockProcessor.cs
@@ -152,7 +152,7 @@ public class BlockProcessor
    /// <summary>
    /// Gets the current stack of <see cref="Block"/> being processed.
    /// </summary>
-    private List<BlockWrapper> OpenedBlocks { get; } = new();
+    private List<BlockWrapper> OpenedBlocks { get; } = [];

    private bool ContinueProcessingLine { get; set; }

--- a/src/Markdig/Parsers/FencedCodeBlockParser.cs
+++ b/src/Markdig/Parsers/FencedCodeBlockParser.cs
@@ -20,7 +20,7 @@ public class FencedCodeBlockParser : FencedBlockParserBase<FencedCodeBlock>
    /// </summary>
    public FencedCodeBlockParser()
    {
-        OpeningCharacters = new[] {'`', '~'};
+        OpeningCharacters = ['`', '~'];
        InfoPrefix = DefaultInfoPrefix;
    }

--- a/src/Markdig/Parsers/HeadingBlockParser.cs
+++ b/src/Markdig/Parsers/HeadingBlockParser.cs
@@ -20,7 +20,7 @@ public class HeadingBlockParser : BlockParser, IAttributesParseable
    /// </summary>
    public HeadingBlockParser()
    {
-        OpeningCharacters = new[] {'#'};
+        OpeningCharacters = ['#'];
    }

    /// <summary>
--- a/src/Markdig/Parsers/HtmlBlockParser.cs
+++ b/src/Markdig/Parsers/HtmlBlockParser.cs
@@ -18,7 +18,7 @@ public class HtmlBlockParser : BlockParser
    /// </summary>
    public HtmlBlockParser()
    {
-        OpeningCharacters = new[] { '<' };
+        OpeningCharacters = ['<'];
    }
       
    public override BlockState TryOpen(BlockProcessor processor)
--- a/src/Markdig/Parsers/InlineProcessor.cs
+++ b/src/Markdig/Parsers/InlineProcessor.cs
@@ -26,9 +26,11 @@ public delegate void ProcessInlineDelegate(InlineProcessor processor, Inline? in
 /// </summary>
 public class InlineProcessor
 {
-    private readonly List<StringLineGroup.LineOffset> lineOffsets = new();
+    private readonly List<StringLineGroup.LineOffset> lineOffsets = [];
    private int previousSliceOffset;
    private int previousLineIndexForSliceOffset;
+    internal ContainerBlock? PreviousContainerToReplace;
+    internal ContainerBlock? NewContainerToReplace;

    /// <summary>
    /// Initializes a new instance of the <see cref="InlineProcessor" /> class.
@@ -203,6 +205,24 @@ public class InlineProcessor
        return 0;
    }

+    /// <summary>
+    /// Replace a parent container. This method is experimental and should be used with caution.
+    /// </summary>
+    /// <param name="previousParentContainer">The previous parent container to replace</param>
+    /// <param name="newParentContainer">The new parent container</param>
+    /// <exception cref="InvalidOperationException">If a new parent container has been already setup.</exception>
+    internal void ReplaceParentContainer(ContainerBlock previousParentContainer, ContainerBlock newParentContainer)
+    {
+        // Limitation for now, only one parent container can be replaced.
+        if (PreviousContainerToReplace != null)
+        {
+            throw new InvalidOperationException("A block is already being replaced");
+        }
+
+        PreviousContainerToReplace = previousParentContainer;
+        NewContainerToReplace = newParentContainer;
+    }
+
    /// <summary>
    /// Processes the inline of the specified <see cref="LeafBlock"/>.
    /// </summary>
@@ -211,6 +231,9 @@ public class InlineProcessor
    {
        if (leafBlock is null) ThrowHelper.ArgumentNullException_leafBlock();

+        PreviousContainerToReplace = null;
+        NewContainerToReplace = null;
+
        // clear parser states
        Array.Clear(ParserStates, 0, ParserStates.Length);

--- a/src/Markdig/Parsers/Inlines/AutolinkInlineParser.cs
+++ b/src/Markdig/Parsers/Inlines/AutolinkInlineParser.cs
@@ -19,7 +19,7 @@ public class AutolinkInlineParser : InlineParser
    /// </summary>
    public AutolinkInlineParser()
    {
-        OpeningCharacters = new[] {'<'};
+        OpeningCharacters = ['<'];
        EnableHtmlParsing = true;
    }

--- a/src/Markdig/Parsers/Inlines/CodeInlineParser.cs
+++ b/src/Markdig/Parsers/Inlines/CodeInlineParser.cs
@@ -21,7 +21,7 @@ public class CodeInlineParser : InlineParser
    /// </summary>
    public CodeInlineParser()
    {
-        OpeningCharacters = new[] { '`' };
+        OpeningCharacters = ['`'];
    }

    public override bool Match(InlineProcessor processor, ref StringSlice slice)
--- a/src/Markdig/Parsers/Inlines/EmphasisInlineParser.cs
+++ b/src/Markdig/Parsers/Inlines/EmphasisInlineParser.cs
@@ -20,7 +20,7 @@ namespace Markdig.Parsers.Inlines;
 public class EmphasisInlineParser : InlineParser, IPostInlineProcessor
 {
    private CharacterMap<EmphasisDescriptor>? emphasisMap;
-    private readonly DelimitersObjectCache inlinesCache = new DelimitersObjectCache();
+    private readonly DelimitersObjectCache inlinesCache = new();

    [Obsolete("Use TryCreateEmphasisInlineDelegate instead", error: false)]
    public delegate EmphasisInline CreateEmphasisInlineDelegate(char emphasisChar, bool isStrong);
@@ -31,11 +31,11 @@ public class EmphasisInlineParser : InlineParser, IPostInlineProcessor
    /// </summary>
    public EmphasisInlineParser()
    {
-        EmphasisDescriptors = new List<EmphasisDescriptor>()
-        {
+        EmphasisDescriptors =
+        [
            new EmphasisDescriptor('*', 1, 2, true),
            new EmphasisDescriptor('_', 1, 2, false)
-        };
+        ];
    }

    /// <summary>
@@ -65,7 +65,7 @@ public class EmphasisInlineParser : InlineParser, IPostInlineProcessor
    /// </summary>
    [Obsolete("Use TryCreateEmphasisInlineList instead", error: false)]
    public CreateEmphasisInlineDelegate? CreateEmphasisInline { get; set; }
-    public readonly List<TryCreateEmphasisInlineDelegate> TryCreateEmphasisInlineList = new List<TryCreateEmphasisInlineDelegate>();
+    public readonly List<TryCreateEmphasisInlineDelegate> TryCreateEmphasisInlineList = [];

    public override void Initialize()
    {
--- a/src/Markdig/Parsers/Inlines/EscapeInlineParser.cs
+++ b/src/Markdig/Parsers/Inlines/EscapeInlineParser.cs
@@ -15,7 +15,7 @@ public class EscapeInlineParser : InlineParser
 {
    public EscapeInlineParser()
    {
-        OpeningCharacters = new[] {'\\'};
+        OpeningCharacters = ['\\'];
    }

    public override bool Match(InlineProcessor processor, ref StringSlice slice)
--- a/src/Markdig/Parsers/Inlines/HtmlEntityParser.cs
+++ b/src/Markdig/Parsers/Inlines/HtmlEntityParser.cs
@@ -21,7 +21,7 @@ public class HtmlEntityParser : InlineParser
    /// </summary>
    public HtmlEntityParser()
    {
-        OpeningCharacters = new[] {'&'};
+        OpeningCharacters = ['&'];
    }

    public static bool TryParse(ref StringSlice slice, [NotNullWhen(true)] out string? literal, out int match)
--- a/src/Markdig/Parsers/Inlines/LineBreakInlineParser.cs
+++ b/src/Markdig/Parsers/Inlines/LineBreakInlineParser.cs
@@ -18,7 +18,7 @@ public class LineBreakInlineParser : InlineParser
    /// </summary>
    public LineBreakInlineParser()
    {
-        OpeningCharacters = new[] { '\n', '\r' };
+        OpeningCharacters = ['\n', '\r'];
    }

    /// <summary>
--- a/src/Markdig/Parsers/Inlines/LinkInlineParser.cs
+++ b/src/Markdig/Parsers/Inlines/LinkInlineParser.cs
@@ -19,7 +19,7 @@ public class LinkInlineParser : InlineParser
    /// </summary>
    public LinkInlineParser()
    {
-        OpeningCharacters = new[] {'[', ']', '!'};
+        OpeningCharacters = ['[', ']', '!'];
    }

    public override bool Match(InlineProcessor processor, ref StringSlice slice)
@@ -322,7 +322,7 @@ public class LinkInlineParser : InlineParser

        if (label != null || LinkHelper.TryParseLabelTrivia(ref text, true, out label, out labelSpan))
        {
-            SourceSpan labelWithTrivia = new SourceSpan(labelSpan.Start, labelSpan.End);
+            var labelWithTrivia = new SourceSpan(labelSpan.Start, labelSpan.End);
            if (isLabelSpanLocal)
            {
                labelSpan = inlineState.GetSourcePositionFromLocalSpan(labelSpan);
--- a/src/Markdig/Parsers/MarkdownParser.cs
+++ b/src/Markdig/Parsers/MarkdownParser.cs
@@ -170,6 +170,40 @@ public static class MarkdownParser
                    if (leafBlock.ProcessInlines)
                    {
                        inlineProcessor.ProcessInlineLeaf(leafBlock);
+
+                        // Experimental code to handle a replacement of a parent container
+                        // Not satisfied with this code, so we are keeping it internal for now
+                        if (inlineProcessor.PreviousContainerToReplace != null)
+                        {
+                            if (container == inlineProcessor.PreviousContainerToReplace)
+                            {
+                                item = new ContainerItem(inlineProcessor.NewContainerToReplace!) { Index = item.Index };
+                                container = item.Container;
+                            }
+                            else
+                            {
+                                bool parentBlockFound = false;
+                                for (int i = blockCount - 2; i >= 0; i--)
+                                {
+                                    ref var parentBlock = ref blocks[i];
+                                    if (parentBlock.Container == inlineProcessor.PreviousContainerToReplace)
+                                    {
+                                        parentBlock = new ContainerItem(inlineProcessor.NewContainerToReplace!) { Index = parentBlock.Index };
+                                        parentBlockFound = true;
+                                        break;
+                                    }
+                                }
+
+                                if (!parentBlockFound)
+                                {
+                                    throw new InvalidOperationException("Cannot find the parent block to replace");
+                                }
+                            }
+
+                            inlineProcessor.PreviousContainerToReplace = null;
+                            inlineProcessor.NewContainerToReplace = null;
+                        }
+
                        if (leafBlock.RemoveAfterProcessInlines)
                        {
                            container.RemoveAt(item.Index);
@@ -210,16 +244,10 @@ public static class MarkdownParser
        }
    }

-    private struct ContainerItem
+    private struct ContainerItem(ContainerBlock container)
    {
-        public ContainerItem(ContainerBlock container)
-        {
-            Container = container;
-            Index = 0;
-        }
+        public readonly ContainerBlock Container = container;

-        public readonly ContainerBlock Container;
-
-        public int Index;
+        public int Index = 0;
    }
 }
--- a/src/Markdig/Parsers/OrderedListItemParser.cs
+++ b/src/Markdig/Parsers/OrderedListItemParser.cs
@@ -15,7 +15,7 @@ public abstract class OrderedListItemParser : ListItemParser
    /// </summary>
    protected OrderedListItemParser()
    {
-        OrderedDelimiters = new[] { '.', ')' };
+        OrderedDelimiters = ['.', ')'];
    }

    /// <summary>
--- a/src/Markdig/Parsers/ParagraphBlockParser.cs
+++ b/src/Markdig/Parsers/ParagraphBlockParser.cs
@@ -171,13 +171,9 @@ public class ParagraphBlockParser : BlockParser
        {
            count = line.CountAndSkipChar(headingChar);

-            if (line.IsEmpty)
-            {
-                return headingChar;
-            }
-
-            while (line.NextChar().IsSpaceOrTab())
+            while (line.CurrentChar.IsSpaceOrTab())
            {
+                line.NextChar();
            }

            if (line.IsEmpty)
--- a/src/Markdig/Parsers/QuoteBlockParser.cs
+++ b/src/Markdig/Parsers/QuoteBlockParser.cs
@@ -18,7 +18,7 @@ public class QuoteBlockParser : BlockParser
    /// </summary>
    public QuoteBlockParser()
    {
-        OpeningCharacters = new[] {'>'};
+        OpeningCharacters = ['>'];
    }

    public override BlockState TryOpen(BlockProcessor processor)
--- a/src/Markdig/Parsers/ThematicBreakParser.cs
+++ b/src/Markdig/Parsers/ThematicBreakParser.cs
@@ -16,14 +16,14 @@ public class ThematicBreakParser : BlockParser
    /// <summary>
    /// A singleton instance used by other parsers.
    /// </summary>
-    public static readonly ThematicBreakParser Default = new ThematicBreakParser();
+    public static readonly ThematicBreakParser Default = new();

    /// <summary>
    /// Initializes a new instance of the <see cref="ThematicBreakParser"/> class.
    /// </summary>
    public ThematicBreakParser()
    {
-        OpeningCharacters = new[] {'-', '_', '*'};
+        OpeningCharacters = ['-', '_', '*'];
    }

    public override BlockState TryOpen(BlockProcessor processor)
--- a/src/Markdig/Parsers/UnorderedListItemParser.cs
+++ b/src/Markdig/Parsers/UnorderedListItemParser.cs
@@ -15,7 +15,7 @@ public class UnorderedListItemParser : ListItemParser
    /// </summary>
    public UnorderedListItemParser()
    {
-        OpeningCharacters = new [] {'-', '+', '*'};
+        OpeningCharacters = ['-', '+', '*'];
    }

    public override bool TryParse(BlockProcessor state, char pendingBulletType, out ListInfo result)
--- a/src/Markdig/Polyfills/NullableAttributes.cs
+++ b/src/Markdig/Polyfills/NullableAttributes.cs
@@ -23,7 +23,7 @@ internal sealed class AllowNullAttribute : Attribute { }
 #if !NET5_0_OR_GREATER
 internal sealed class MemberNotNullAttribute : Attribute
 {
-    public MemberNotNullAttribute(string member) => Members = new[] { member };
+    public MemberNotNullAttribute(string member) => Members = [member];

    public MemberNotNullAttribute(params string[] members) => Members = members;

--- a/src/Markdig/Renderers/Html/CodeBlockRenderer.cs
+++ b/src/Markdig/Renderers/Html/CodeBlockRenderer.cs
@@ -1,5 +1,5 @@
 // Copyright (c) Alexandre Mutel. All rights reserved.
-// This file is licensed under the BSD-Clause 2 license. 
+// This file is licensed under the BSD-Clause 2 license.
 // See the license.txt file in the project root for more information.

 using Markdig.Parsers;
@@ -13,8 +13,6 @@ namespace Markdig.Renderers.Html;
 /// <seealso cref="HtmlObjectRenderer{CodeBlock}" />
 public class CodeBlockRenderer : HtmlObjectRenderer<CodeBlock>
 {
-    private HashSet<string>? _blocksAsDiv;
-
    /// <summary>
    /// Initializes a new instance of the <see cref="CodeBlockRenderer"/> class.
    /// </summary>
@@ -25,23 +23,32 @@ public class CodeBlockRenderer : HtmlObjectRenderer<CodeBlock>
    /// <summary>
    /// Gets a map of fenced code block infos that should be rendered as div blocks instead of pre/code blocks.
    /// </summary>
-    public HashSet<string> BlocksAsDiv => _blocksAsDiv ??= new HashSet<string>(StringComparer.OrdinalIgnoreCase);
+    public HashSet<string> BlocksAsDiv { get; } = new HashSet<string>(StringComparer.OrdinalIgnoreCase);
+
+    /// <summary>
+    /// Gets a map of custom block mapping to render as custom blocks instead of pre/code blocks.
+    /// For example defining {"mermaid", "pre"} will render a block with info `mermaid` as a `pre` block but without the code HTML element.
+    /// </summary>
+    public Dictionary<string, string> BlockMapping { get; } = new Dictionary<string, string>(StringComparer.OrdinalIgnoreCase);

    protected override void Write(HtmlRenderer renderer, CodeBlock obj)
    {
        renderer.EnsureLine();

-        if (_blocksAsDiv is not null && (obj as FencedCodeBlock)?.Info is string info && _blocksAsDiv.Contains(info))
+        if ((obj as FencedCodeBlock)?.Info is string info && (BlocksAsDiv.Contains(info) || BlockMapping.ContainsKey(info)))
        {
            var infoPrefix = (obj.Parser as FencedCodeBlockParser)?.InfoPrefix ??
                             FencedCodeBlockParser.DefaultInfoPrefix;

+            var htmlBlock = BlockMapping.TryGetValue(info, out var blockType) ? blockType : "div";
+
            // We are replacing the HTML attribute `language-mylang` by `mylang` only for a div block
            // NOTE that we are allocating a closure here

            if (renderer.EnableHtmlForBlock)
            {
-                renderer.Write("<div")
+                renderer.WriteRaw('<');
+                renderer.Write(htmlBlock)
                        .WriteAttributes(obj.TryGetAttributes(),
                            cls => cls.StartsWith(infoPrefix, StringComparison.Ordinal) ? cls.Substring(infoPrefix.Length) : cls)
                        .WriteRaw('>');
@@ -51,7 +58,7 @@ public class CodeBlockRenderer : HtmlObjectRenderer<CodeBlock>

            if (renderer.EnableHtmlForBlock)
            {
-                renderer.WriteLine("</div>");
+                renderer.Write("</").Write(htmlBlock).WriteLine(">");
            }
        }
        else
--- a/src/Markdig/Renderers/Html/HeadingRenderer.cs
+++ b/src/Markdig/Renderers/Html/HeadingRenderer.cs
@@ -12,14 +12,14 @@ namespace Markdig.Renderers.Html;
 /// <seealso cref="HtmlObjectRenderer{HeadingBlock}" />
 public class HeadingRenderer : HtmlObjectRenderer<HeadingBlock>
 {
-    private static readonly string[] HeadingTexts = {
+    private static readonly string[] HeadingTexts = [
        "h1",
        "h2",
        "h3",
        "h4",
        "h5",
        "h6",
-    };
+    ];

    protected override void Write(HtmlRenderer renderer, HeadingBlock obj)
    {
--- a/src/Markdig/Renderers/HtmlRenderer.cs
+++ b/src/Markdig/Renderers/HtmlRenderer.cs
@@ -144,6 +144,8 @@ public class HtmlRenderer : TextRendererBase<HtmlRenderer>
        return this;
    }

+    private static readonly SearchValues<char> s_escapedChars = SearchValues.Create("<>&\"");
+
    /// <summary>
    /// Writes the content escaped for HTML.
    /// </summary>
@@ -159,7 +161,7 @@ public class HtmlRenderer : TextRendererBase<HtmlRenderer>
            {
                int indexOfCharToEscape = softEscape
                    ? content.IndexOfAny('<', '&')
-                    : content.IndexOfAny("<>&\"");
+                    : content.IndexOfAny(s_escapedChars);

                if ((uint)indexOfCharToEscape >= (uint)content.Length)
                {
--- a/src/Markdig/Renderers/MarkdownObjectRenderer.cs
+++ b/src/Markdig/Renderers/MarkdownObjectRenderer.cs
@@ -28,15 +28,15 @@ public abstract class MarkdownObjectRenderer<TRenderer, TObject> : IMarkdownObje

    public virtual void Write(RendererBase renderer, MarkdownObject obj)
    {
-        var htmlRenderer = (TRenderer)renderer;
+        var typedRenderer = (TRenderer)renderer;
        var typedObj = (TObject)obj;

-        if (_tryWriters is not null && TryWrite(htmlRenderer, typedObj))
+        if (_tryWriters is not null && TryWrite(typedRenderer, typedObj))
        {
            return;
        }

-        Write(htmlRenderer, typedObj);
+        Write(typedRenderer, typedObj);
    }

    private bool TryWrite(TRenderer renderer, TObject obj)
--- a/src/Markdig/Renderers/Normalize/CodeBlockRenderer.cs
+++ b/src/Markdig/Renderers/Normalize/CodeBlockRenderer.cs
@@ -18,9 +18,9 @@ public class CodeBlockRenderer : NormalizeObjectRenderer<CodeBlock>
    {
        if (obj is FencedCodeBlock fencedCodeBlock)
        {
-            var fencedCharCount = Math.Min(fencedCodeBlock.OpeningFencedCharCount, fencedCodeBlock.ClosingFencedCharCount);
-            var opening = new string(fencedCodeBlock.FencedChar, fencedCharCount);
-            renderer.Write(opening);
+            int fencedCharCount = Math.Min(fencedCodeBlock.OpeningFencedCharCount, fencedCodeBlock.ClosingFencedCharCount);
+
+            renderer.Write(fencedCodeBlock.FencedChar, fencedCharCount);
            if (fencedCodeBlock.Info != null)
            {
                renderer.Write(fencedCodeBlock.Info);
@@ -41,7 +41,7 @@ public class CodeBlockRenderer : NormalizeObjectRenderer<CodeBlock>
            renderer.WriteLine();

            renderer.WriteLeafRawLines(obj, true);
-            renderer.Write(opening);
+            renderer.Write(fencedCodeBlock.FencedChar, fencedCharCount);
        }
        else
        {
--- a/src/Markdig/Renderers/Normalize/HeadingRenderer.cs
+++ b/src/Markdig/Renderers/Normalize/HeadingRenderer.cs
@@ -12,22 +12,27 @@ namespace Markdig.Renderers.Normalize;
 /// <seealso cref="NormalizeObjectRenderer{HeadingBlock}" />
 public class HeadingRenderer : NormalizeObjectRenderer<HeadingBlock>
 {
-    private static readonly string[] HeadingTexts = {
+    private static readonly string[] HeadingTexts = [
        "#",
        "##",
        "###",
        "####",
        "#####",
        "######",
-    };
+    ];

    protected override void Write(NormalizeRenderer renderer, HeadingBlock obj)
-    {
-        var headingText = obj.Level > 0 && obj.Level <= 6
-            ? HeadingTexts[obj.Level - 1]
-            : new string('#', obj.Level);
+    {        
+        if (obj.Level is > 0 and <= 6)
+        {
+            renderer.Write(HeadingTexts[obj.Level - 1]);
+        }
+        else
+        {
+            renderer.Write('#', obj.Level);            
+        }        

-        renderer.Write(headingText).Write(' ');
+        renderer.Write(' ');
        renderer.WriteLeafInline(obj);

        renderer.FinishBlock(renderer.Options.EmptyLineAfterHeading);
--- a/src/Markdig/Renderers/Normalize/Inlines/CodeInlineRenderer.cs
+++ b/src/Markdig/Renderers/Normalize/Inlines/CodeInlineRenderer.cs
@@ -31,8 +31,8 @@ public class CodeInlineRenderer : NormalizeObjectRenderer<CodeInline>
            if (delimiterCount < count)
                delimiterCount = count;
        }
-        var delimiterRun = new string(obj.Delimiter, delimiterCount + 1);
-        renderer.Write(delimiterRun);
+
+        renderer.Write(obj.Delimiter, delimiterCount + 1);
        if (content.Length != 0)
        {
            if (content[0] == obj.Delimiter)
@@ -49,6 +49,6 @@ public class CodeInlineRenderer : NormalizeObjectRenderer<CodeInline>
        {
            renderer.Write(' ');
        }
-        renderer.Write(delimiterRun);
+        renderer.Write(obj.Delimiter, delimiterCount + 1);
    }
 }
--- a/src/Markdig/Renderers/Normalize/Inlines/EmphasisInlineRenderer.cs
+++ b/src/Markdig/Renderers/Normalize/Inlines/EmphasisInlineRenderer.cs
@@ -14,9 +14,8 @@ public class EmphasisInlineRenderer : NormalizeObjectRenderer<EmphasisInline>
 {
    protected override void Write(NormalizeRenderer renderer, EmphasisInline obj)
    {
-        var emphasisText = new string(obj.DelimiterChar, obj.DelimiterCount);
-        renderer.Write(emphasisText);
+        renderer.Write(obj.DelimiterChar, obj.DelimiterCount);
        renderer.WriteChildren(obj);
-        renderer.Write(emphasisText);
+        renderer.Write(obj.DelimiterChar, obj.DelimiterCount);
    }
 }
--- a/src/Markdig/Renderers/Roundtrip/CodeBlockRenderer.cs
+++ b/src/Markdig/Renderers/Roundtrip/CodeBlockRenderer.cs
@@ -19,8 +19,7 @@ public class CodeBlockRenderer : RoundtripObjectRenderer<CodeBlock>
        if (obj is FencedCodeBlock fencedCodeBlock)
        {
            renderer.Write(obj.TriviaBefore);
-            var opening = new string(fencedCodeBlock.FencedChar, fencedCodeBlock.OpeningFencedCharCount);
-            renderer.Write(opening);
+            renderer.Write(fencedCodeBlock.FencedChar, fencedCodeBlock.OpeningFencedCharCount);

            if (!fencedCodeBlock.TriviaAfterFencedChar.IsEmpty)
            {
@@ -56,9 +55,8 @@ public class CodeBlockRenderer : RoundtripObjectRenderer<CodeBlock>
            renderer.WriteLeafRawLines(obj);

            renderer.Write(fencedCodeBlock.TriviaBeforeClosingFence);
-            var closing = new string(fencedCodeBlock.FencedChar, fencedCodeBlock.ClosingFencedCharCount);
-            renderer.Write(closing);
-            if (!string.IsNullOrEmpty(closing))
+            renderer.Write(fencedCodeBlock.FencedChar, fencedCodeBlock.ClosingFencedCharCount);
+            if (fencedCodeBlock.ClosingFencedCharCount > 0)
            {
                // See example 207: "> ```\nfoo\n```"
                renderer.WriteLine(obj.NewLine);
--- a/src/Markdig/Renderers/Roundtrip/HeadingRenderer.cs
+++ b/src/Markdig/Renderers/Roundtrip/HeadingRenderer.cs
@@ -12,14 +12,14 @@ namespace Markdig.Renderers.Roundtrip;
 /// <seealso cref="RoundtripObjectRenderer{HeadingBlock}" />
 public class HeadingRenderer : RoundtripObjectRenderer<HeadingBlock>
 {
-    private static readonly string[] HeadingTexts = {
+    private static readonly string[] HeadingTexts = [
        "#",
        "##",
        "###",
        "####",
        "#####",
        "######",
-    };
+    ];

    protected override void Write(RoundtripRenderer renderer, HeadingBlock obj)
    {
@@ -28,12 +28,11 @@ public class HeadingRenderer : RoundtripObjectRenderer<HeadingBlock>
            renderer.RenderLinesBefore(obj);

            var headingChar = obj.Level == 1 ? '=' : '-';
-            var line = new string(headingChar, obj.HeaderCharCount);

            renderer.WriteLeafInline(obj);
            renderer.WriteLine(obj.SetextNewline);
            renderer.Write(obj.TriviaBefore);
-            renderer.Write(line);
+            renderer.Write(headingChar, obj.HeaderCharCount);
            renderer.WriteLine(obj.NewLine);
            renderer.Write(obj.TriviaAfter);

@@ -43,12 +42,17 @@ public class HeadingRenderer : RoundtripObjectRenderer<HeadingBlock>
        {
            renderer.RenderLinesBefore(obj);

-            var headingText = obj.Level > 0 && obj.Level <= 6
-                ? HeadingTexts[obj.Level - 1]
-                : new string('#', obj.Level);
-
            renderer.Write(obj.TriviaBefore);
-            renderer.Write(headingText);
+
+            if (obj.Level is > 0 and <= 6)
+            {
+                renderer.Write(HeadingTexts[obj.Level - 1]);
+            }
+            else
+            {
+                renderer.Write('#', obj.Level);
+            }
+
            renderer.Write(obj.TriviaAfterAtxHeaderChar);
            renderer.WriteLeafInline(obj);
            renderer.Write(obj.TriviaAfter);
--- a/src/Markdig/Renderers/Roundtrip/Inlines/CodeInlineRenderer.cs
+++ b/src/Markdig/Renderers/Roundtrip/Inlines/CodeInlineRenderer.cs
@@ -14,12 +14,11 @@ public class CodeInlineRenderer : RoundtripObjectRenderer<CodeInline>
 {
    protected override void Write(RoundtripRenderer renderer, CodeInline obj)
    {
-        var delimiterRun = new string(obj.Delimiter, obj.DelimiterCount);
-        renderer.Write(delimiterRun);
+        renderer.Write(obj.Delimiter, obj.DelimiterCount);
        if (!obj.ContentSpan.IsEmpty)
        {
            renderer.Write(obj.ContentWithTrivia);
        }
-        renderer.Write(delimiterRun);
+        renderer.Write(obj.Delimiter, obj.DelimiterCount);
    }
 }
--- a/src/Markdig/Renderers/Roundtrip/Inlines/EmphasisInlineRenderer.cs
+++ b/src/Markdig/Renderers/Roundtrip/Inlines/EmphasisInlineRenderer.cs
@@ -14,9 +14,8 @@ public class EmphasisInlineRenderer : RoundtripObjectRenderer<EmphasisInline>
 {
    protected override void Write(RoundtripRenderer renderer, EmphasisInline obj)
    {
-        var emphasisText = new string(obj.DelimiterChar, obj.DelimiterCount);
-        renderer.Write(emphasisText);
+        renderer.Write(obj.DelimiterChar, obj.DelimiterCount);
        renderer.WriteChildren(obj);
-        renderer.Write(emphasisText);
+        renderer.Write(obj.DelimiterChar, obj.DelimiterCount);
    }
 }
--- a/src/Markdig/Renderers/TextRendererBase.cs
+++ b/src/Markdig/Renderers/TextRendererBase.cs
@@ -211,6 +211,25 @@ public abstract class TextRendererBase<T> : TextRendererBase where T : TextRende
        return (T)this;
    }

+    /// <summary>
+    /// Writes the specified char repeated a specified number of times.
+    /// </summary>
+    /// <param name="c">The char to write.</param>
+    /// <param name="count">The number of times to write the char.</param>
+    /// <returns>This instance</returns>
+    [MethodImpl(MethodImplOptions.AggressiveInlining)]
+    internal T Write(char c, int count)
+    {
+        WriteIndent();        
+        
+        for (int i = 0; i < count; i++)
+        {
+            Writer.Write(c);
+        }        
+
+        return (T)this;
+    }
+
    /// <summary>
    /// Writes the specified slice.
    /// </summary>
--- a/src/Markdig/Syntax/CodeBlock.cs
+++ b/src/Markdig/Syntax/CodeBlock.cs
@@ -21,7 +21,7 @@ public class CodeBlock : LeafBlock
    }

    private List<CodeBlockLine>? _codeBlockLines;
-    public List<CodeBlockLine> CodeBlockLines => _codeBlockLines ??= new();
+    public List<CodeBlockLine> CodeBlockLines => _codeBlockLines ??= [];

    /// <summary>
    /// Initializes a new instance of the <see cref="CodeBlock"/> class.
--- a/src/Markdig/Syntax/ContainerBlock.cs
+++ b/src/Markdig/Syntax/ContainerBlock.cs
@@ -27,7 +27,7 @@ public abstract class ContainerBlock : Block, IList<Block>, IReadOnlyList<Block>
    /// <param name="parser">The parser used to create this block.</param>
    protected ContainerBlock(BlockParser? parser) : base(parser)
    {
-        _children = Array.Empty<BlockWrapper>();
+        _children = [];
        SetTypeKind(isInline: false, isContainer: true);
    }

@@ -301,14 +301,9 @@ public abstract class ContainerBlock : Block, IList<Block>, IReadOnlyList<Block>

    #endregion

-    private sealed class BlockComparisonWrapper : IComparer<BlockWrapper>
+    private sealed class BlockComparisonWrapper(Comparison<Block> comparison) : IComparer<BlockWrapper>
    {
-        private readonly Comparison<Block> _comparison;
-
-        public BlockComparisonWrapper(Comparison<Block> comparison)
-        {
-            _comparison = comparison;
-        }
+        private readonly Comparison<Block> _comparison = comparison;

        public int Compare(BlockWrapper x, BlockWrapper y)
        {
@@ -316,14 +311,9 @@ public abstract class ContainerBlock : Block, IList<Block>, IReadOnlyList<Block>
        }
    }

-    private sealed class BlockComparerWrapper : IComparer<BlockWrapper>
+    private sealed class BlockComparerWrapper(IComparer<Block> comparer) : IComparer<BlockWrapper>
    {
-        private readonly IComparer<Block> _comparer;
-
-        public BlockComparerWrapper(IComparer<Block> comparer)
-        {
-            _comparer = comparer;
-        }
+        private readonly IComparer<Block> _comparer = comparer;

        public int Compare(BlockWrapper x, BlockWrapper y)
        {
--- a/src/Markdig/Syntax/MarkdownObject.cs
+++ b/src/Markdig/Syntax/MarkdownObject.cs
@@ -155,16 +155,10 @@ public abstract class MarkdownObject : IMarkdownObject

    private class DataEntriesAndTrivia
    {
-        private struct DataEntry
+        private struct DataEntry(object key, object value)
        {
-            public readonly object Key;
-            public object Value;
-
-            public DataEntry(object key, object value)
-            {
-                Key = key;
-                Value = value;
-            }
+            public readonly object Key = key;
+            public object Value = value;
        }

        private DataEntry[]? _entries;
--- a/src/Markdig/Syntax/QuoteBlock.cs
+++ b/src/Markdig/Syntax/QuoteBlock.cs
@@ -19,7 +19,7 @@ public class QuoteBlock : ContainerBlock
    /// Initializes a new instance of the <see cref="QuoteBlock"/> class.
    /// </summary>
    /// <param name="parser">The parser used to create this block.</param>
-    public QuoteBlock(BlockParser parser) : base(parser)
+    public QuoteBlock(BlockParser? parser) : base(parser)
    {
    }

@@ -42,7 +42,7 @@ public class QuoteBlock : ContainerBlock
 public class QuoteBlockLine
 {
    /// <summary>
-    /// Gets or sets trivia occuring before the first quote character.
+    /// Gets or sets trivia occurring before the first quote character.
    /// </summary>
    public StringSlice TriviaBefore { get; set; }

--- a/src/Markdig/Syntax/SourceSpan.cs
+++ b/src/Markdig/Syntax/SourceSpan.cs
@@ -37,26 +37,26 @@ public struct SourceSpan : IEquatable<SourceSpan>
    /// <summary>
    /// Gets the character length of this element within the original source code.
    /// </summary>
-    public int Length => End - Start + 1;
+    public readonly int Length => End - Start + 1;

-    public bool IsEmpty => Start > End;
+    public readonly bool IsEmpty => Start > End;

    public SourceSpan MoveForward(int count)
    {
        return new SourceSpan(Start + count, End + count);
    }

-    public bool Equals(SourceSpan other)
+    public readonly bool Equals(SourceSpan other)
    {
        return Start == other.Start && End == other.End;
    }

-    public override bool Equals(object? obj)
+    public override readonly bool Equals(object? obj)
    {
        return obj is SourceSpan sourceSpan && Equals(sourceSpan);
    }

-    public override int GetHashCode()
+    public override readonly int GetHashCode()
    {
        unchecked
        {
@@ -74,7 +74,7 @@ public struct SourceSpan : IEquatable<SourceSpan>
        return !left.Equals(right);
    }

-    public override string ToString()
+    public override readonly string ToString()
    {
        return $"{Start}-{End}";
    }
--- a/src/SpecFileGen/Program.cs
+++ b/src/SpecFileGen/Program.cs
@@ -61,6 +61,7 @@ class Program
    static readonly Spec[] Specs = new[]
    {
        new Spec("CommonMarkSpecs",     "CommonMark.md",                ""),
+        new Spec("Alert Blocks",        "AlertBlockSpecs.md",           "advanced"),
        new Spec("Pipe Tables",         "PipeTableSpecs.md",            "pipetables|advanced"),
        new Spec("GFM Pipe Tables",     "PipeTableGfmSpecs.md",         "gfm-pipetables"),
        new Spec("Footnotes",           "FootnotesSpecs.md",            "footnotes|advanced"),
--- a/src/SpecFileGen/SpecFileGen.csproj
+++ b/src/SpecFileGen/SpecFileGen.csproj
@@ -2,7 +2,7 @@

  <PropertyGroup>
    <OutputType>Exe</OutputType>
-    <TargetFramework>net6.0</TargetFramework>
+    <TargetFramework>net8.0</TargetFramework>
    <ImplicitUsings>enable</ImplicitUsings>
    <IsPackable>false</IsPackable>
  </PropertyGroup>
--- a/src/UnicodeNormDApp/UnicodeNormDApp.csproj
+++ b/src/UnicodeNormDApp/UnicodeNormDApp.csproj
@@ -1,7 +1,7 @@
 <Project Sdk="Microsoft.NET.Sdk">
  <PropertyGroup>
    <OutputType>Exe</OutputType>
-    <TargetFramework>net6.0</TargetFramework>
+    <TargetFramework>net8.0</TargetFramework>
    <IsPackable>false</IsPackable>
    <ImplicitUsings>enable</ImplicitUsings>
  </PropertyGroup>
--- a/src/markdig.sln.DotSettings
+++ b/src/markdig.sln.DotSettings
@@ -3,7 +3,9 @@
 This file is licensed under the BSD-Clause 2 license. &#xD;
 See the license.txt file in the project root for more information.</s:String>
 	<s:String x:Key="/Default/CodeStyle/Naming/CSharpNaming/PredefinedNamingRules/=PrivateInstanceFields/@EntryIndexedValue">&lt;Policy Inspect="True" Prefix="" Suffix="" Style="aaBb" /&gt;</s:String>
+	<s:String x:Key="/Default/CodeStyle/Naming/CSharpNaming/UserRules/=4a98fdf6_002D7d98_002D4f5a_002Dafeb_002Dea44ad98c70c/@EntryIndexedValue">&lt;Policy&gt;&lt;Descriptor Staticness="Instance" AccessRightKinds="Private" Description="Instance fields (private)"&gt;&lt;ElementKinds&gt;&lt;Kind Name="FIELD" /&gt;&lt;Kind Name="READONLY_FIELD" /&gt;&lt;/ElementKinds&gt;&lt;/Descriptor&gt;&lt;Policy Inspect="True" Prefix="" Suffix="" Style="aaBb" /&gt;&lt;/Policy&gt;</s:String>
 	<s:Boolean x:Key="/Default/Environment/SettingsMigration/IsMigratorApplied/=JetBrains_002EReSharper_002EFeature_002EServices_002ECodeCleanup_002EFileHeader_002EFileHeaderSettingsMigrate/@EntryIndexedValue">True</s:Boolean>
+	<s:Boolean x:Key="/Default/Environment/SettingsMigration/IsMigratorApplied/=JetBrains_002EReSharper_002EPsi_002ECSharp_002ECodeStyle_002ESettingsUpgrade_002EPredefinedNamingRulesToUserRulesUpgrade/@EntryIndexedValue">True</s:Boolean>
 	<s:String x:Key="/Default/Environment/UnitTesting/NUnitProvider/SetCurrentDirectoryTo/@EntryValue">TestFolder</s:String>
 	<s:Boolean x:Key="/Default/UserDictionary/Words/=Autolink/@EntryIndexedValue">True</s:Boolean>
 	<s:Boolean x:Key="/Default/UserDictionary/Words/=Inlines/@EntryIndexedValue">True</s:Boolean>
--- a/src/mdtoc/mdtoc.csproj
+++ b/src/mdtoc/mdtoc.csproj
@@ -1,7 +1,7 @@
 <Project Sdk="Microsoft.NET.Sdk">
  <PropertyGroup>
    <OutputType>Exe</OutputType>
-    <TargetFramework>net6.0</TargetFramework>
+    <TargetFramework>net8.0</TargetFramework>
    <IsPackable>false</IsPackable>
    <ImplicitUsings>enable</ImplicitUsings>
    <Nullable>enable</Nullable>
Author	SHA1	Message	Date
Alexandre Mutel	f734e91568	Merge pull request #823 from xoofx/fix-mermaid Update DiagramExtension.cs	2024-10-25 22:01:40 +02:00
Alexandre Mutel	090e6d791a	Update DiagramExtension.cs Update tests	2024-10-25 21:58:28 +02:00
Alexandre Mutel	41bdb0f0ab	Merge pull request #817 from ehsankalafchi/rename-variable Rename a variable	2024-10-01 20:53:47 +02:00
Ehsan Kalafchi	b27ef11240	Rename a variable	2024-09-26 13:51:18 +02:00
Alexandre Mutel	dfa2c94b88	Merge pull request #808 from digvijayad/master Fix mermaid link in readme.md	2024-07-18 06:50:19 +02:00
Digvijay Naruka	89330f3524	Update mermaid link in readme.md Updated broken old GitHub pages link to the new domain https://mermaid.js.org/	2024-07-17 12:44:26 +05:30
Alexandre Mutel	1a1bbecc46	Merge pull request #786 from MartinZikmund/feature/youtube-short-support Support for YouTube Shorts embedding	2024-04-09 21:11:30 +02:00
Martin Zikmund	68bd3074b2	Add support for YouTube Shorts embedding	2024-04-01 17:42:46 +02:00
Martin Zikmund	e486903687	Test support for YouTube Shorts embedding	2024-04-01 17:42:12 +02:00
Alexandre Mutel	8e22754db4	Merge pull request #785 from toothache/fix_issues Fix issues for math span calculation	2024-03-29 21:23:31 +01:00
teethache	93d88ab994	Fix math span calculation.	2024-03-27 07:06:56 +08:00
Alexandre Mutel	000393f46a	Fix invalid setext heading (#785 )	2024-03-26 21:02:48 +01:00
Alexandre Mutel	a5796890e1	Merge pull request #784 from Abrynos/case-invariant-alerts Make alert block headers case-invariant	2024-03-25 21:26:19 +01:00
Sebastian Göls	c19ba5b0eb	Add fallback value in order to mark unknown alert kinds in some way as well	2024-03-25 12:29:22 +01:00
Sebastian Göls	03390e4f71	Misc.	2024-03-18 10:28:36 +01:00
Sebastian Göls	42bd65caaf	Apply feedback	2024-03-18 09:18:39 +01:00
Sebastian Göls	b7ae04bdba	Make alert block headers case-invariant	2024-03-18 09:04:47 +01:00
Alexandre Mutel	391f376fa2	Merge pull request #782 from Abrynos/bootstrap-alerts Add bootstrap alert renderer	2024-03-18 08:11:19 +01:00
Sebastian Göls	f9e96bc9c9	Apply feedback	2024-03-18 07:48:22 +01:00
Alexandre Mutel	c75a11ec32	Update parsing-extensions.md	2024-03-17 15:01:14 +01:00
Alexandre Mutel	fd226d53e9	Update readme.md	2024-03-17 14:59:05 +01:00
Sebastian Göls	7132584996	Add bootstrap alert renderer	2024-03-15 11:28:48 +01:00
Alexandre Mutel	f48331d6c7	Fix missing code in commit for #780	2024-03-14 18:34:44 +01:00
Alexandre Mutel	6549d3b726	Fixes #780 where only the first paragraph of an alert block is processed.	2024-03-14 18:31:11 +01:00
Alexandre Mutel	d434f00355	Merge pull request #779 from toothache/fix_math_span Fix math source span	2024-03-14 08:14:58 +01:00
Alexandre Mutel	b62a12d32d	Add support for GitHub alert blocks (#776 ) * Add support for GitHub alert blocks * Fix alert for "must come first in a quote block" * Fix comment * Update src/Markdig/Extensions/Alerts/AlertBlockRenderer.cs Co-authored-by: Miha Zupan <mihazupan.zupan1@gmail.com> * Update src/Markdig/MarkdownExtensions.cs Co-authored-by: Miha Zupan <mihazupan.zupan1@gmail.com> * Fix parsing of alert block with multiple children blocks * Allow null for BlockParser ctor argument of QuoteBlock --------- Co-authored-by: Miha Zupan <mihazupan.zupan1@gmail.com>	2024-03-14 08:09:42 +01:00
teethache	3c7edaa82d	Fix math source span.	2024-03-11 20:35:54 +08:00
Alexandre Mutel	fcb56fb037	Merge pull request #773 from hhyyrylainen/patch-1 Fixed a typo in MathSpecs.md	2024-02-29 08:21:10 +01:00
Henri Hyyryläinen	50bc6cadfc	Fix typo in MathSpecs.md	2024-02-18 18:58:04 +02:00
Alexandre Mutel	201aa4ef73	Try to use the reusable workflow	2024-02-17 07:11:33 +01:00
Alexandre Mutel	adce9797d6	Use ubuntu for the CI	2024-02-17 06:49:39 +01:00
Alexandre Mutel	fb71dff0ec	Fix tests	2024-02-17 06:48:47 +01:00
Alexandre Mutel	399570941a	Remove net7.0 from CI	2024-02-17 06:47:31 +01:00
Alexandre Mutel	2f903697e2	Update projects to net8.0	2024-02-17 06:43:07 +01:00
Alexandre Mutel	eb8fe15679	Update ci.yml with nuget config	2024-02-13 09:29:26 +01:00
Alexandre Mutel	8f008e45ca	Add nuget.org only config	2024-02-13 09:29:26 +01:00
Alexandre Mutel	0014ec4138	Merge pull request #769 from carbon/cq3 Eliminate various string allocations	2024-02-13 08:25:40 +01:00
Jason Nelson	2ca05ccad7	Eliminate string allocation in CodeInlineRenderer	2024-02-09 13:13:31 -08:00
Jason Nelson	6a15c804bc	Add test coverage for headlines with > 6 # characters	2024-02-09 12:54:52 -08:00
Jason Nelson	0446959623	Add TextRendererBase.Write(char c, int count) method, and eliminate various string allocations	2024-02-09 12:54:30 -08:00
Alexandre Mutel	e6afddbaa0	Merge pull request #761 from carbon/collection-expressions Use C# 12 syntax	2023-12-18 21:11:50 +01:00
Jason Nelson	a377239e91	Use null-coalescing assignment operator	2023-12-14 20:08:53 -08:00
Jason Nelson	35aa304faf	Remove unused using statement	2023-12-14 19:56:08 -08:00
Jason Nelson	e4568979ec	Fix typo	2023-12-14 19:55:45 -08:00
Jason Nelson	3470ec0d54	Make various members readonly on SourceSpan	2023-12-14 19:55:37 -08:00
Jason Nelson	113ef7f215	Use primary constructors (part 2)	2023-12-14 19:50:09 -08:00
Jason Nelson	4cb4b68883	Use collection expressions (part 5)	2023-12-14 19:43:15 -08:00
Jason Nelson	64ae344b74	Use collection expressions (part 4)	2023-12-14 15:41:07 -08:00
Jason Nelson	b5f3c9fc67	Use collection expressions (part 3)	2023-12-14 12:57:11 -08:00
Jason Nelson	8a88fd0557	Use collection expressions (part 2)	2023-12-14 12:46:40 -08:00
Jason Nelson	cc7623989d	Fix typo on private method	2023-12-14 12:39:19 -08:00
Jason Nelson	b6a7acf5fc	Use primary constructors	2023-12-14 12:35:22 -08:00
Jason Nelson	804a6f0dbc	Use accelerated IndexOfAny in one more case	2023-12-14 12:32:52 -08:00
Jason Nelson	342e264988	Use collection expressions	2023-12-14 12:32:34 -08:00