# Module Heap_intf

    module Heap_intf: sig .. end

of_sexp and bin_io functions aren't supplied for heaps due to the difficulties in reconstructing the correct comparison function when de-serializing.

    module type S = sig .. end

of_sexp and bin_io functions aren't supplied for heaps due to the difficulties in reconstructing the correct comparison function when de-serializing.
Mutation of the heap during iteration is not supported, but there is no check to prevent it. The behavior of a heap that is mutated during iteration is undefined.
Even though these two functions are part of Container.S1, they are documented separately to make sure there is no confusion. They are independent of the comparison function used to order the heap. Instead, a traversal of the entire structure is done using the provided `cmp` function to find a min or max.

If you want to access the smallest element of the heap according to the heap's comparison function in constant time, you should use `top`.
`create ?min_size ~cmp` returns a new min-heap that can store `min_size` elements without reallocations, using ordering function `cmp`.

The top of the heap is the smallest element as determined by the provided comparison function. In particular, if `cmp x y < 0` then `x` will be "on top of" `y` in the heap.

Memory use is surprising in two ways:

1. The underlying pool never shrinks, so current memory use will at least be proportional to the largest number of elements that the heap has ever held.

2. Not all the memory is freed upon `remove`, but rather after some number of subsequent `pop` operations. Alternating `add` and `remove` operations can therefore use unbounded memory.
`min_size` (see `create`) will be set to the size of the input array or list.
returns the top (i.e., smallest) element of the heap
`remove_top t` does nothing if `t` is empty
This removes and returns the top (i.e. least) element
`pop_if t cond` returns `Some top_element` of `t` if it satisfies condition `cond`, removing it, or `None` in any other case.
`copy t` returns a shallow copy