Interoptopus

🦀 → 🐙 → Python, C#, C, ...

FFI bindings to your favorite language. Composable. Explicit. Escape hatches included.

If you ...

wrote an extern "C" API in Rust
need C#, Python, C, ... bindings to your library, all at the same time
prefer having fine-grained control over your API and interop generation
would like to use quality-of-life patterns on both sides (e.g., options, slices, 'classes') where feasible
create your own bindings for a not-yet supported language
want all your binding-related information (e.g., documentation) in Rust code

... then Interoptopus might be for you.

not yet used in production
somewhat verbose if you don't own most of your types (still possible, just more work)
if you target only a single language and don't care about your FFI layer other solutions might be better

Assume you have written this Rust FFI code:

```rust use interoptopus::{ffifunction, ffitype};

[ffi_type]

pub struct Vec3f32 { pub x: f32, pub y: f32, pub z: f32, }

pub extern "C" fn mygamefunction(input: Option<&Vec3f32>) -> Vec3f32 { Vec3f32 { x: 2.0, y: 4.0, z: 6.0 } }

interoptopus::inventoryfunction!(ffiinventory, [], [mygamefunction], []); ```

You can now use one of these backends to generate interop code:

| Language | Crate | Sample Output | Comment | | --- | --- | --- | --- | | C# (incl. Unity) | interoptopusbackendcsharp | Interop.cs | Built-in. | | C | interoptopusbackendc | myheader.h | Built-in.| | Python CFFI | interoptopusbackendcpythoncffi | reference.py | Built-in. | | Your language | Write your own backend! | - | See existing backends. |

See the reference project for a list of all supported features.

June 13, 2021 - Pre-alpha. Has generated C#, C, Python-CFFI bindings at least once, many things missing, untested.

PRs are welcome.

Bug fixes can be submitted directly. Major changes should be filed as issues first.
Anything that would make previously working bindings change behavior or stop compiling is a major change; which doesn't mean we're opposed to breaking stuff before 1.0, just that we'd like to talk about it before it happens.
New features or patterns must be materialized in the reference project and accompanied by an interop test (i.e., a backend test running C# / Python against a DLL invoking that code) in at least one included backend.