sol2/examples/usertype.cpp

116 lines
3.3 KiB
C++

#define SOL_CHECK_ARGUMENTS 1
#include <sol.hpp>
#include <iostream>
#include "assert.hpp"
#include <cmath>
struct foo {
private:
std::string name;
public:
foo(std::string name): name(std::string(name)) {}
void print() {
std::cout << name << '\n';
}
int test(int x) {
return static_cast<int>(name.length() + x);
}
};
struct vector {
private:
float x = 0;
float y = 0;
public:
vector() = default;
vector(float x): x(x) {}
vector(float x, float y): x(x), y(y) {}
bool is_unit() const {
return (x * x + y * y) == 1.f;
}
};
struct variables {
bool low_gravity = false;
int boost_level = 0;
};
int main() {
std::cout << "=== usertype example ===" << std::endl;
sol::state lua;
lua.open_libraries(sol::lib::base, sol::lib::math);
// the simplest way to create a class is through
// sol::state::new_userdata
// the first template is the class type
// the rest are the constructor parameters
// using new_userdata you can only have one constructor
// you must make sure that the name of the function
// goes before the member function pointer
lua.new_usertype<foo, std::string>("foo", "print", &foo::print, "test", &foo::test);
// making the class from lua is simple
// same with calling member functions
lua.script("x = foo.new('test')\n"
"x:print()\n"
"y = x:test(10)");
auto y = lua.get<int>("y");
std::cout << y << std::endl; // show 14
// if you want a class to have more than one constructor
// the way to do so is through set_userdata and creating
// a userdata yourself with constructor types
{
// Notice the brace: this means we're in a new scope
// first, define the different types of constructors
// notice here that the return type
// on the function-type doesn't exactly matter,
// which allows you to use a shorter class name/void
// if necessary
sol::constructors<vector(), vector(float), void(float, float)> ctor;
// the only template parameter is the class type
// the first argument of construction is the name
// second is the constructor types
// then the rest are function name and member function pointer pairs
sol::usertype<vector> utype(ctor, "is_unit", &vector::is_unit);
// then you must register it
lua.set_usertype("vector", utype);
// You can throw away the usertype after you set it: you do NOT
// have to keep it around
// cleanup happens automagically
}
// calling it is the same as new_userdata
lua.script("v = vector.new()\n"
"v = vector.new(12)\n"
"v = vector.new(10, 10)\n"
"assert(not v:is_unit())\n");
// You can even have C++-like member-variable-access
// just pass is public member variables in the same style as functions
lua.new_usertype<variables>("variables", "low_gravity", &variables::low_gravity, "boost_level", &variables::boost_level);
// making the class from lua is simple
// same with calling member functions/variables
lua.script("local vars = variables.new()\n"
"assert(not vars.low_gravity)\n"
"vars.low_gravity = true\n"
"local x = vars.low_gravity\n"
"assert(x)");
std::cout << std::endl;
}