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#define SOL_ALL_SAFETIES_ON 1
#include <sol/sol.hpp>
#include <cmath>
struct vec {
double x;
double y;
vec() : x(0), y(0) {
}
vec(double x, double y) : x(x), y(y) {
}
vec operator-(const vec& right) const {
return vec(x - right.x, y - right.y);
}
};
double dot(const vec& left, const vec& right) {
return left.x * right.x + left.y * right.y;
}
vec operator+(const vec& left, const vec& right) {
return vec(left.x + right.x, left.y + right.y);
}
int main() {
sol::state lua;
lua.open_libraries();
lua.new_usertype<vec>(
"vec",
sol::constructors<vec(), vec(double, double)>(),
"dot",
&dot,
"norm",
[](const vec& self) {
double len = std::sqrt(dot(self, self));
return vec(self.x / len, self.y / len);
},
// we use `sol::resolve` because other operator+ can
// exist in the (global) namespace
sol::meta_function::addition,
sol::resolve<vec(const vec&, const vec&)>(::operator+),
sol::meta_function::subtraction,
&vec::operator-);
lua.script(R"(
v1 = vec.new(1, 0)
v2 = vec.new(0, 1)
-- as "member function"
d1 = v1:dot(v2)
-- as "static" / "free function"
d2 = vec.dot(v1, v2)
assert(d1 == d2)
-- doesn't matter if
-- bound as free function
-- or member function:
a1 = v1 + v2
s1 = v1 - v2
)");
vec& a1 = lua["a1"];
vec& s1 = lua["s1"];
SOL_ASSERT(a1.x == 1 && a1.y == 1);
SOL_ASSERT(s1.x == 1 && s1.y == -1);
lua["a2"] = lua["a1"];
lua.script(R"(
assert(a1 == a2)
)");
return 0;
}
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