add yaml serialization library

src/logic/scripting/lua/libs/libyaml.cpp

@@ -0,0 +1,20 @@
+#include "coders/yaml.hpp"
+#include "api_lua.hpp"
+
+static int l_stringify(lua::State* L) {
+    auto value = lua::tovalue(L, 1);
+    auto string = yaml::stringify(value);
+    return lua::pushstring(L, string);
+}
+
+static int l_parse(lua::State* L) {
+    auto string = lua::require_string(L, 1);
+    auto element = yaml::parse("[string]", string);
+    return lua::pushvalue(L, element);
+}
+
+const luaL_Reg yamllib[] = {
+    {"tostring", lua::wrap<l_stringify>},
+    {"parse", lua::wrap<l_parse>},
+    {NULL, NULL}
+};