future_form_ffi 0.1.0

FFI support for future_form: host-driven polling, opaque handles, and effect slots
Documentation 
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51

# Simple Counter

A minimal FFI example demonstrating `future_form`'s host-driven polling
pattern. A counter service exposes async methods that foreign hosts
(Go, Java, Python) drive to completion via `poll_once()`.

## What this demonstrates

- Writing a trait generic over `FutureForm` (`Counter<K>`)
- Generating concrete impls with `#[future_form(Sendable)]`
- Wrapping a `BoxFuture` in a `HostHandle` for C ABI export
- The same trait impl serving both tokio `.await` and FFI `poll_once()`

## Structure

```
counter_simple/
├── counter/        Domain logic: Counter<K> trait + SimpleCounter
├── rust_bridge/    C ABI + JNI bridge
├── tokio_host/     Rust host using tokio (same trait impl)
├── go_host/        Go host via CGo
├── java_host/      Java host via JNI
├── python_host/    Python host via ctypes
└── run_test.sh     Build + run across all hosts
```

## Running

From the workspace root, using `nix develop .#ffi` for foreign toolchains:

```sh
./future_form_ffi/examples/counter_simple/run_test.sh
```

Or run individual hosts:

```sh
# Tokio (no extra toolchains needed)
cargo run --manifest-path future_form_ffi/examples/counter_simple/tokio_host/Cargo.toml

# Go
cargo build --manifest-path future_form_ffi/examples/counter_simple/rust_bridge/Cargo.toml
cd future_form_ffi/examples/counter_simple/go_host && go run .
```

## Next steps

For effect handling (host-fulfilled timestamps, logging), see the
[counter_effects](../counter_effects/) example. For concurrent
per-future effect slots, see the [key_value_store](../key_value_store/)
example.