using maddy for markdown parsing

maddy/latexblockparser.h

@@ -0,0 +1,124 @@
+/*
+ * 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 {
+
+// -----------------------------------------------------------------------------
+
+/**
+ * LatexBlockParser
+ *
+ * Support for https://www.mathjax.org/
+ * Be aware, that if you want to make MathJax work, you need also their
+ * JavaScript library added to your HTML code.
+ * maddy does not itself add that code to be more flexible in how you write your
+ * head and full body.
+ *
+ * From Markdown: `$$` surrounded text
+ *
+ * ```
+ *  $$some formula
+ *  $$
+ * ```
+ *
+ * To HTML:
+ *
+ * ```
+ * $$some formula
+ * $$
+ * ```
+ *
+ * @class
+ */
+class LatexBlockParser : public BlockParser
+{
+public:
+  /**
+   * ctor
+   *
+   * @method
+   * @param {std::function<void(std::string&)>} parseLineCallback
+   * @param {std::function<std::shared_ptr<BlockParser>(const std::string&
+   * line)>} getBlockParserForLineCallback
+   */
+  LatexBlockParser(
+    std::function<void(std::string&)> parseLineCallback,
+    std::function<std::shared_ptr<BlockParser>(const std::string& line)>
+      getBlockParserForLineCallback
+  )
+    : BlockParser(parseLineCallback, getBlockParserForLineCallback)
+    , isStarted(false)
+    , isFinished(false)
+  {}
+
+  /**
+   * IsStartingLine
+   *
+   * If the line starts with two dollars, then it is a latex block.
+   *
+   * ```
+   *  $$
+   * ```
+   *
+   * @method
+   * @param {const std::string&} line
+   * @return {bool}
+   */
+  static bool IsStartingLine(const std::string& line)
+  {
+    static std::regex re(R"(^(?:\$){2}(.*)$)");
+    return std::regex_match(line, re);
+  }
+
+  /**
+   * IsFinished
+   *
+   * @method
+   * @return {bool}
+   */
+  bool IsFinished() const override { return this->isFinished; }
+
+protected:
+  bool isInlineBlockAllowed() const override { return false; }
+
+  bool isLineParserAllowed() const override { return false; }
+
+  void parseBlock(std::string& line) override
+  {
+    if (!this->isStarted && line.substr(0, 2) == "$$")
+    {
+      this->isStarted = true;
+      this->isFinished = false;
+    }
+
+    if (this->isStarted && !this->isFinished && line.size() > 1 &&
+        line.substr(line.size() - 2, 2) == "$$")
+    {
+      this->isFinished = true;
+      this->isStarted = false;
+    }
+
+    line += "\n";
+  }
+
+private:
+  bool isStarted;
+  bool isFinished;
+}; // class LatexBlockParser
+
+// -----------------------------------------------------------------------------
+
+} // namespace maddy