Add token literals to the lua parser

luprex/cpp/core/luastack.hpp

@@ -413,6 +413,10 @@ private:
     // and the result is: CH0*37^11 + CH1*37^10 + ... + CH11*37^0.
     // This fixed-width encoding ensures that numeric ordering matches
     // lexicographic ordering of the original strings.
+    //
+    // WARNING: The Lua lexer in llex.c contains a duplicate of this
+    // encoding logic (in the '@' token literal case). If you change
+    // the encoding here, you must update llex.c to match.
     // Returns zero if the string is empty, too long, or contains
     // invalid characters.
     //

luprex/cpp/core/pprint.cpp

@@ -64,7 +64,7 @@ public:
         }
         case LUA_TLIGHTUSERDATA: {
             LuaToken token = LS_.cktoken(val);
-            (*output_) << "[" << token.str() << "]";
+            (*output_) << "@" << token.str();
             return;
         }
         case LUA_TT_GENERAL: {