PrioQ

alias P = int;
alias V = string;
alias PQ = PriorityQueue!(P, V);
PQ pq;

import std.typecons: tuple;

pq.insert(10, `10`);
pq.insert(11, `11`);
pq.insert(tuple(3, `3`));

foreach (const e; pq) {}    // iteration
assert(!pq.empty);          // shouldn't consume queue

assert(pq.front == tuple(3, `3`));
pq.popFront();
assert(pq.front == tuple(10, `10`));
pq.popFront();
assert(pq.front == tuple(11, `11`));
pq.popFront();

assert(pq.empty);