Expand description
Persistent heap of mutable cells.
The heap is a BTreeMap from monotonically-allocated Addresses to
Values. Every operation that conceptually mutates the heap (alloc,
store, retain) instead returns a new Heap value; the receiver is
left untouched. No Rc, Arc, RefCell, Cell, or Mutex is used to
provide shared mutability.
The trade-off is performance: each non-read operation clones the existing cell map. This is acceptable for a falsification spike and an explicit mirror of the persistent-data-structure pattern that the user’s no- interior-mutability rule pushes the design toward.