add option to print help in markdown form

src/utils/optionsparser.cc

@@ -120,6 +120,10 @@ bool OptionsParser::ProcessFlags(const std::vector<std::string>& args) {
       ShowHelp();
       return false;
     }
+    if (param == "--help-md") {
+      ShowHelpMd();
+      return false;
+    }
     if (param == "--show-hidden") {
       ShowHidden();
       continue;
@@ -264,6 +268,88 @@ void OptionsParser::ShowHelp() const {
   }
 }
 
+namespace {
+std::string EscapeMd(const std::string& input) {
+  const std::string kSpecial = "~#<>&*_\\[]+-`|:\n\r";
+  std::string s = input;
+  size_t pos = 0;
+  while ((pos = s.find_first_of(kSpecial, pos)) != std::string::npos) {
+    switch (s[pos]) {
+      case '<':
+        s.replace(pos, 1, "&lt;");
+        pos += 4;
+        break;
+      case '>':
+        s.replace(pos, 1, "&gt;");
+        pos += 4;
+        break;
+      case '&':
+        s.replace(pos, 1, "&amp;");
+        pos += 5;
+        break;
+      case '\n':
+        s.replace(pos, 1, "<br/>");
+        pos += 5;
+        break;
+      case '\r':
+        s.erase(pos, 1);
+        break;
+      default:
+        s.insert(pos, "\\");
+        pos += 2;
+    }
+  }
+  return s;
+}
+}  // namespace
+
+void OptionsParser::ShowHelpMd() const {
+  std::cout << "\n# Lc0 options\n";
+  std::cout << "\n*Flag*|*UCI option*|Description\n---|---|------\n";
+  std::cout << "**--help**, **-h**||Show help and exit.\n";
+  for (const auto& option : options_) {
+    if (option->hidden_) continue;
+    if (!option->GetLongFlag().empty()) {
+      std::cout << "**--" << option->GetLongFlag() << "**";
+    }
+    if (option->GetShortFlag()) {
+      std::cout << ", **-" << option->GetShortFlag() << "**";
+    }
+    std::cout << '|';
+    if (!option->GetUciOption().empty()) {
+      std::cout << "**" << option->GetUciOption() << "**";
+    }
+    std::cout << '|' << EscapeMd(option->GetHelpText());
+    std::string help = option->GetHelp(defaults_);
+    size_t idx = help.rfind("DEFAULT:");
+    if (idx != std::string::npos) {
+      help.replace(idx, 8, "*Default value:* `");
+      size_t idx2 = help.rfind("MIN:");
+      if (idx2 != std::string::npos) {
+        help.replace(idx2, 4, "`<br/>*Minimum value:* `");
+      }
+      idx2 = help.rfind("MAX:");
+      if (idx2 != std::string::npos) {
+        help.replace(idx2, 4, "`<br/>*Maximum value:* `");
+      }
+      idx2 = help.rfind("VALUES:");
+      if (idx2 != std::string::npos) {
+        help.replace(idx2, 7, "`<br/>*Allowed values:* `");
+        while ((idx2 = help.find(",", idx2)) != std::string::npos) {
+          help.replace(idx2, 1, "`, `");
+          idx2 += 4;
+        }
+      }
+      idx2 = help.rfind("]");
+      if (idx2 != std::string::npos) {
+        help.erase(idx2);
+      }
+      std::cout << "<br/>" << help.substr(idx) << "`";
+    }
+    std::cout << "\n";
+  }
+}
+
 void OptionsParser::ShowHidden() const {
   for (const auto& option : options_) option->hidden_ = false;
 }

src/utils/optionsparser.h

@@ -135,8 +135,10 @@ class OptionsParser {
   void AddContext(const std::string&);
 
  private:
-  // Prints help to std::cerr.
+  // Prints help to std::cout.
   void ShowHelp() const;
+  // Prints markdown formatted help to std::cout.
+  void ShowHelpMd() const;
   // Make all hidden options visible.
   void ShowHidden() const;
   // Returns an option based on the long flag.