C++ allows the for following:
struct Demo
{
float a, b, c, d;
Demo() { a = b = c = d = 0.0f; }
Demo(float _a, float _b, float _c, float _d) {
a = _a;
b = _b;
c = _c;
d = _d;
}
float operator[] (size_t i) const { return (&a)[i]; } //[3]
float& operator[] (size_t i) { return (&a)[i]; } //[4]
}
void fun(float col[3])
{
// do fun stuff
}
void moreFun(const Demo& d = Demo(0.1f, 0.3f, 7.5f, 1.5f)) // [1]
{
// you guessed it... more fun stuff
}
int main(int argv, const char** argc)
{
Demo inst = Demo(0.1f, 0.3f, 7.5f, 1.5f);
fun((float*)&inst); // [2]
moreFun();
return 0;
}
I'm seeking some pointers on how to define these in D so that I
can instantiate them in D while still linking to the associated
C++ library or object file for the implementation. The main
points of contention are at [1] and [2] because I have no idea
how to accomplish these. I assume that I can accomplish [3] and
[4] with opIndex() and opIndexAssign(), however I'm not
understanding the slicing of the memory address at the first
member variable. I know that by indexing the memory address at
the member variable we are able treat the struct as an array but
i do not understand how to implement it in D.
I read the documentation at
https://dlang.org/spec/cpp_interface.html and
https://dlang.org/articles/cpptod.html but it was not clear "to
me" how to overcome these issues.
Andrew
