more nntpchan-daemon stuff

contrib/backends/nntpchan-daemon/libmustache/visitor/render_node.hpp

@@ -0,0 +1,56 @@
+#pragma once
+
+#include <sstream>
+#include <boost/variant/static_visitor.hpp>
+
+#include "../render_context.hpp"
+#include "mstch/mstch.hpp"
+#include "../utils.hpp"
+
+namespace mstch {
+
+class render_node: public boost::static_visitor<std::string> {
+ public:
+  enum class flag { none, escape_html };
+  render_node(render_context& ctx, flag p_flag = flag::none):
+      m_ctx(ctx), m_flag(p_flag)
+  {
+  }
+
+  template<class T>
+  std::string operator()(const T&) const {
+    return "";
+  }
+
+  std::string operator()(const int& value) const {
+    return std::to_string(value);
+  }
+
+  std::string operator()(const double& value) const {
+    std::stringstream ss;
+    ss << value;
+    return ss.str();
+  }
+
+  std::string operator()(const bool& value) const {
+    return value ? "true" : "false";
+  }
+
+  std::string operator()(const lambda& value) const {
+    template_type interpreted{value([this](const mstch::node& n) {
+      return visit(render_node(m_ctx), n);
+    })};
+    auto rendered = render_context::push(m_ctx).render(interpreted);
+    return (m_flag == flag::escape_html) ? html_escape(rendered) : rendered;
+  }
+
+  std::string operator()(const std::string& value) const {
+    return (m_flag == flag::escape_html) ? html_escape(value) : value;
+  }
+
+ private:
+  render_context& m_ctx;
+  flag m_flag;
+};
+
+}