italicparser: Add first version

Signed-off-by: Patrick José Pereira <patrickelectric@gmail.com>

include/maddy/italicparser.h

@@ -0,0 +1,50 @@
+/*
+ * This project is licensed under the MIT license. For more information see the
+ * LICENSE file.
+ */
+#pragma once
+
+// -----------------------------------------------------------------------------
+
+#include <string>
+#include <regex>
+
+#include "maddy/lineparser.h"
+
+// -----------------------------------------------------------------------------
+
+namespace maddy {
+
+// -----------------------------------------------------------------------------
+
+/**
+ * ItalicParser
+ *
+ * @class
+ */
+class ItalicParser : public LineParser
+{
+public:
+  /**
+   * Parse
+   *
+   * From Markdown: `text *text*`
+   *
+   * To HTML: `text <i>text</i>`
+   *
+   * @method
+   * @param {std::string&} line The line to interpret
+   * @return {void}
+   */
+  void
+  Parse(std::string& line) override
+  {
+    std::regex re("(?!.*`.*|.*<code>.*)\\*(?!.*`.*|.*<\\/code>.*)([^\\*]*)\\*(?!.*`.*|.*<\\/code>.*)");
+    static std::string replacement = "<i>$1</i>";
+    line = std::regex_replace(line, re, replacement);
+  }
+}; // class ItalicParser
+
+// -----------------------------------------------------------------------------
+
+} // namespace maddy

include/maddy/parser.h

@@ -25,6 +25,7 @@
 #include "maddy/emphasizedparser.h"
 #include "maddy/imageparser.h"
 #include "maddy/inlinecodeparser.h"
+#include "maddy/italicparser.h"
 #include "maddy/linkparser.h"
 #include "maddy/strikethroughparser.h"
 #include "maddy/strongparser.h"
@@ -56,6 +57,7 @@ public:
     : emphasizedParser(std::make_shared<EmphasizedParser>())
     , imageParser(std::make_shared<ImageParser>())
     , inlineCodeParser(std::make_shared<InlineCodeParser>())
+    , italicParser(std::make_shared<ItalicParser>())
     , linkParser(std::make_shared<LinkParser>())
     , strikeThroughParser(std::make_shared<StrikeThroughParser>())
     , strongParser(std::make_shared<StrongParser>())
@@ -112,6 +114,7 @@ private:
   std::shared_ptr<EmphasizedParser> emphasizedParser;
   std::shared_ptr<ImageParser> imageParser;
   std::shared_ptr<InlineCodeParser> inlineCodeParser;
+  std::shared_ptr<ItalicParser> italicParser;
   std::shared_ptr<LinkParser> linkParser;
   std::shared_ptr<StrikeThroughParser> strikeThroughParser;
   std::shared_ptr<StrongParser> strongParser;
@@ -131,6 +134,8 @@ private:
     this->strikeThroughParser->Parse(line);
 
     this->inlineCodeParser->Parse(line);
+
+    this->italicParser->Parse(line);
   }
 
   std::shared_ptr<BlockParser>