Registering a function inside a table

[iganinja]

Hi

Is there a way to register a function from C++ so it is contained in a table? So I can call from Lua this way:

local v = MyStuff.doSomething(...)

Thanks

[ThePhD]

Yes. Make the table in lua or in C++, get the table, and then call mytable.set_function( ... );, like you would with anything. E.g...

sol::state lua;
sol::table mystuff = lua.create_table("MyStuff");
mystuff.set_function( "doSomething", &doSomething );

If the table already exists, you can just do sol::table mystuff = lua.get<sol::table>( "MyStuff" ); instead of creating the table. Shorter syntax is sol::table mystuff = lua["MyStuff"];, which I believe SHOULD work (there might be an exception for tables in the current main/develop branches, which could be changed on my develop branch).

[iganinja]

Thanks for the answer. I get a compilation error in create_table() call, which I think is the same error as in #68. I will try the patch of this issue to see if everything works (I am using the develop branch, btw)

[ThePhD]

No problem. If you run into further build issues just look at the mega pull-request references in #68, that is, everything in #62 (or just at ThePhD/sol, branch develop). Should all be resolved there.

[iganinja]

I used #68 patch and it worked correctly. Anyway thanks for the #62 and your develop branch tips, I will keep them in mind.

[iganinja]

Hi again

I replaced my old sol files with the ones from ThePhD/sol, branch develop and I get compiler erros. The first one is this:

\sol\function_types.hpp:171: error: expected primary-expression before 'decltype'
decltype(auto) r = stack::call(L, 0, types<return_type>(), ta, fx);
^

Any clue about that?

Thanks

[ThePhD]

You're most likely compiling with -std=c++11. That's a C++14 feature. I have to backpeddle and fix that, but it'll require some extra lines of code...

[iganinja]

Thanks for the fast answer.

I was compiling with -std=c++1y flag. I switched to -std=c++14 and now I have other errors. First one:

sol\function.hpp:211: error: 'call' was not declared in this scope
-> decltype(call<Ret...>(std::forward(args)...)) {
^

I am using mingw 4.9.1. Do you think it's due to this version not implementing all the C++14 standard?

[ThePhD]

You should be okay with that. I'm using MinGW 5.x and I had some of the same errors. It was peculiar; it seems g++ didn't have quite the same binding rules for r-value refs to l-value refs in their compiler as VC++, so I had to change how I used std::declval<T>() to make it behave better with g++.

I dare say you should be all set, with the new changes I just pushed.

[iganinja]

I used your latest version and it compiles ok, thank you very much! :) Just in case you want to fix it, it has a warning of no return value in function.hpp in operator = at line 70.

By the way, capturing a variable in a lambda which returns a tuple should be possible, shouldn't it? I am having compilation errors even with your branch:

int a = 0;
luaVM1.set_function("test", [a]()
{
    return std::make_tuple(10, 10.0f);
});

[ThePhD]

What are the errors? That looks like it should work just fine.

[iganinja]

I have this one with the code above:

sol\function_types.hpp:347: error: no matching function for call to 'call(lua_State*&, int, sol::types<int,     float>&, sol::types<>&, main()::<lambda()>&)'
         return_type r = stack::call(L, 0, tr, ta, fx);
                                            ^

[iganinja]

Excuse me ThePhD, your last changes made my code to compile but I missed the linker messages: I am having multiple definition errors like this one:

sol\stack.hpp:578: error: multiple definition of `sol::stack::remove(lua_State*, int, int)'

This happens without the tuple returning stuff, they are not related (should I create another issue for that tuple returning error?)

[ThePhD]

Woops. I forgot an inline. Fixing that and the other error now.

[ThePhD]

Alright, pushed. I will also add a test case for that so I don't forget to do that again.

[iganinja]

It seems sol::function::default_handler scaped your raid ^^U

error: multiple definition of `sol::function::default_handler'

BTW tupple stuff compiles now ;)