--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/3rdparty/maddy/checklistparser.h	Tue Aug 17 11:19:54 2021 +0200
@@ -0,0 +1,140 @@
+/*
+ * This project is licensed under the MIT license. For more information see the
+ * LICENSE file.
+ */
+#pragma once
+
+// -----------------------------------------------------------------------------
+
+#include <functional>
+#include <regex>
+#include <string>
+
+#include "maddy/blockparser.h"
+
+// -----------------------------------------------------------------------------
+
+namespace maddy {
+
+// -----------------------------------------------------------------------------
+
+/**
+ * ChecklistParser
+ *
+ * @class
+ */
+class ChecklistParser : public BlockParser
+{
+public:
+  /**
+   * ctor
+   *
+   * @method
+   * @param {std::function<void(std::string&)>} parseLineCallback
+   * @param {std::function<std::shared_ptr<BlockParser>(const std::string& line)>} getBlockParserForLineCallback
+   */
+   ChecklistParser(
+    std::function<void(std::string&)> parseLineCallback,
+    std::function<std::shared_ptr<BlockParser>(const std::string& line)> getBlockParserForLineCallback
+  )
+    : BlockParser(parseLineCallback, getBlockParserForLineCallback)
+    , isStarted(false)
+    , isFinished(false)
+  {}
+
+  /**
+   * IsStartingLine
+   *
+   * An unordered list starts with `* `.
+   *
+   * @method
+   * @param {const std::string&} line
+   * @return {bool}
+   */
+  static bool
+  IsStartingLine(const std::string& line)
+  {
+    static std::regex re("^- \\[[x| ]\\] .*");
+    return std::regex_match(line, re);
+  }
+
+  /**
+   * IsFinished
+   *
+   * @method
+   * @return {bool}
+   */
+  bool
+  IsFinished() const override
+  {
+    return this->isFinished;
+  }
+
+protected:
+  bool
+  isInlineBlockAllowed() const override
+  {
+    return true;
+  }
+
+  bool
+  isLineParserAllowed() const override
+  {
+    return true;
+  }
+
+  void
+  parseBlock(std::string& line) override
+  {
+    bool isStartOfNewListItem = IsStartingLine(line);
+    uint32_t indentation = getIndentationWidth(line);
+
+    static std::regex lineRegex("^(- )");
+    line = std::regex_replace(line, lineRegex, "");
+
+    static std::regex emptyBoxRegex("^\\[ \\]");
+    static std::string emptyBoxReplacement = "<input type=\"checkbox\"/>";
+    line = std::regex_replace(line, emptyBoxRegex, emptyBoxReplacement);
+
+    static std::regex boxRegex("^\\[x\\]");
+    static std::string boxReplacement = "<input type=\"checkbox\" checked=\"checked\"/>";
+    line = std::regex_replace(line, boxRegex, boxReplacement);
+
+    if (!this->isStarted)
+    {
+      line = "<ul class=\"checklist\"><li><label>" + line;
+      this->isStarted = true;
+      return;
+    }
+
+    if (indentation >= 2)
+    {
+      line = line.substr(2);
+      return;
+    }
+
+    if (
+      line.empty() ||
+      line.find("</label></li><li><label>") != std::string::npos ||
+      line.find("</label></li></ul>") != std::string::npos
+    )
+    {
+      line = "</label></li></ul>" + line;
+      this->isFinished = true;
+      return;
+    }
+
+    if (isStartOfNewListItem)
+    {
+      line = "</label></li><li><label>" + line;
+    }
+  }
+
+private:
+  bool isStarted;
+  bool isFinished;
+}; // class ChecklistParser
+
+// -----------------------------------------------------------------------------
+
+} // namespace maddy