Reflecting C++ classes in Lua scripts about luabridge3 HOT 6 CLOSED

Should be possible by accessing class metatable and using the internal keys luabridge use. Will try to provide some working snippets as soon as i'm back to the laptop.

from luabridge3.

Do you need to access them from lua or c++ ?

from luabridge3.

    luabridge::setHideMetatables(false);

    luabridge::getGlobalNamespace(L)
        .addFunction("getMetatableClass", [](const luabridge::LuaRef& ref) -> luabridge::LuaRef
        {
            if (!ref.isTable())
                return luabridge::LuaRef(ref.state());

            ref.push();
            luabridge::lua_rawgetp(ref.state(), -1, luabridge::detail::getClassKey());

            auto mt = luabridge::LuaRef::fromStack(ref.state(), 1);

            for (const auto& p : luabridge::pairs(mt))
                std::cout << p.first << " " << p.second << std::endl;

            return mt;
        })
        .beginClass<ExampleStringifiableClass>("ExampleStringifiableClass")
            .addConstructor<void(*) ()>()
            .addFunction("nonConstMethod", [](ExampleStringifiableClass*) {})
            .addFunction("constMethod", [](const ExampleStringifiableClass*) {})
        .endClass();

    runLua(R"(
        local t = ExampleStringifiableClass()
        local mt = getmetatable(t)

        getMetatableClass(mt)
    )");

this will print:

userdata: 0xc07 table: 0x6000017084c0
"__gc" function: 0x600000c09aa0
"nonConstMethod" function: 0x600001708780
userdata: 0x71 "ExampleStringifiableClass"
userdata: 0x5e7 table: 0x600001708600
userdata: 0x6e7 table: 0x6000017085c0
"__newindex" function: 0x600000c09ad0
"__index" function: 0x600000c09b00
"constMethod" function: 0x600001708800

Will provide some facilities to extract this kind of information in a more straight forward way

from luabridge3.

I need to access them from Lua. It is a powerful tool for verifying the correctness of the LuaBridge implementation, as well as presenting the class framework to users as a learning aid.

from luabridge3.

We can design a specific help table for that. So registering a method could push an entry in the table with the description of the method and argument type as seen from c++ (but not name) registered in the class

from luabridge3.

Pre-2019, instead of hard-coded usersdata values the tables above had string keys, _class, _propget, _propset, and _static. (They may have been a _const key too, but if so I never used it.) I only need to be able to iterate them and get their names. I don't need to modify or call the values.

I am currently doing exactly what you suggested and adding helper tables as I register the classes. I use refl-cpp to reflect the C++ classes at compile time so that all of my registrations use the same code. The challenge with refl-cpp is that lack of useful support for overloaded methods. The current support would require me to know and hardcode the function signatures in the central routine where I'm processing them rather than in the lists where I list them, so right now I can't use refl-cpp for everything.

from luabridge3.