# Platform Notes

> USearch for Swift

### What This Binding Does Not Expose

- `cursor` and `searchStream` pull blocking, so a `DenseIndexDeferredOn` lacks them; `contains` is a test over `count`, so the deferred receiver offers `count` alone.
- The constructors address no index yet, so no receiver offers them.

### Design

- __A thin layer over the C ABI.__
  Every name follows `c/usearch/`: a C verb `usearch_dense_<verb>` is a camel-cased `<verb>` here, such as `saveBuffer`, a type is its C name without `usearch_` and `_t`, and enums mirror C enums, never strings.
- __The receiver chooses, the verb stays.__
  The index runs a verb on the calling thread, `on(executor)` blocks on an executor, and `deferred(executor)` submits it, all with the same arguments.
- __Deferred calls use the language's own idioms.__
  `status` polls through `usearch_outcome_status`, `wait()` blocks through `usearch_outcome_wait`, and `try await call.value` runs that wait on a Dispatch thread, so an `async` caller suspends.
- __No life of its own.__
  The binding starts no threads and keeps no queues; releasing a `Deferred` rides its `deinit`, which waits for the call first.
- __Arenas are lent and reused, never shared.__
  Every output whose length scales with the call lands in an arena the caller passes; a view remembers which call wrote it and traps once a later one did.
- __Nothing costs anything until it is used.__
  Submitting a call allocates nothing, and an arena allocates only when a call writes into it.
- __Every wrapper names its C symbol.__
  Each wrapper's documentation names the C function it calls or says it is binding-only, and a verb's argument structure becomes its `Dense*Config`.