add utf8.escape, string.escape & reformat extensions.md

src/logic/scripting/lua/libs/libutf8.cpp

@@ -94,6 +94,11 @@ static int l_encode(lua::State* L) {
     return lua::pushlstring(L, bytes, count);
 }
 
+static int l_escape(lua::State* L) {
+    auto string = lua::require_lstring(L, 1);
+    return lua::pushstring(L, util::escape(string));
+}
+
 const luaL_Reg utf8lib[] = {
     {"tobytes", lua::wrap<l_tobytes>},
     {"tostring", lua::wrap<l_tostring>},
@@ -103,5 +108,6 @@ const luaL_Reg utf8lib[] = {
     {"upper", lua::wrap<l_upper>},
     {"lower", lua::wrap<l_lower>},
     {"encode", lua::wrap<l_encode>},
+    {"escape", lua::wrap<l_escape>},
     {NULL, NULL}
 };

src/util/stringutil.cpp

@@ -7,8 +7,7 @@
 #include <sstream>
 #include <stdexcept>
 
-// TODO: finish
-std::string util::escape(const std::string& s) {
+std::string util::escape(std::string_view s) {
     std::stringstream ss;
     ss << '"';
     size_t pos = 0;

src/util/stringutil.hpp

@@ -8,7 +8,7 @@
 
 namespace util {
     /// @brief Function used for string serialization in text formats
-    std::string escape(const std::string& s);
+    std::string escape(std::string_view s);
 
     /// @brief Function used for error messages
     std::string quote(const std::string& s);