Consider a complex key that is a combination of multiple variables.

struct key
{
  int    foo = 1;
  string bar = "joy";
  string baz = "huzza";
}

The value is a very large object.

struct value
{
  int[4096] payload;
}

There are 10.000s of different keys.
But typically only ~10 different values.

My first idea was to have an array/set of unique value instances and store only the index to the array in the key:ed data structure, this way it's possible to reallocate and extend the array.

Is there an idiomatic way to solve this in D? Or should I just get my hands dirty and do the brute force implementation of the above idea?