Luapp11 is a set of header only lua bindings for C++11. It's designed to abstract away much of the dynamic and stack based nature of the lua C API and provide a nice clean well typed interface between c++11 code and lua code. The only dependency is the c++11 standard library and a c++11 compliant compiler.
The luapp11 api is built around 2 basic types lua::var and lua::val. lua::var represents a specific "place" in the lua environment. It's the primary way values are gotten from and assigned to the lua environment. lua::val is a variant type that can hold any data which can be stored in a lua table. The only type that can be assigned to a lua::var is lua::val but most types can be implicitly converted to a lua::val. This allows you to initialize a lua table like this:
lua::global["foo"] = {
{"bar", 19},
{"baz", true},
{"table", {
{"nested", &userData}
}
}
};
lua::global represents the global of the environment i.e. LUA_GLOBALSINDEX. You can then get data out again in the same way:
lua::var node = lua::global["foo"]["bar"];
node.get<int>(); // == 19
There are 3 templated methods which can be used to probe and extract data from a lua::var. Those being is<T>, as<T>, and get<T>. is<T> returns a boolean which confirms whether a given lua::var can be extracted as a given c++ type. It is guaranteed not to throw. get<T> returns the value for a given lua::var as the specified type T. If the lua::var does not exist in the lua environment, or if the type that is found there is not convertible to T then a lua::exception is thrown. as<T> is a gentler version of get<T> which is basically equivalent to:
template<typename T>
T as(T&& default) {
if(is<T>()) {
return get<T>();
} else {
return default;
}
}
The last major thing that you can do with a lua::var is to attempt to execute it as a lua function. lua::var defines both an operator() and an invoke<T> method. The invoke method is required if you'd like the function you are calling to return a value. Both of them return a lua::result<T> which either contains a lua::error if there was an error executing the lua code. If you prefer exceptions to explicitly handling errors, the result<T> is implicitly convertible to T but might throw an exception if there was an error executing. If you would like to return multiple values from an invocation. You should call invoke with a std::tuple type.
Finally, if you just want to execute lua code, you can do so by calling do_chunk("code here") if you call do_chunk on lua::global, then the code is executed in the global scope. If you call do_chunk on a lua::var then the first return value is assigned to the lua::var that you executed it on.
This is a very early release. There are plans in the works to include file loading (with sandboxing), a threading model, c++ function binding (with lambdas), and other features. See MILESTONES.md for more details.
The MIT License (MIT)
Copyright (c) 2013 Matthew Balkam
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