igen

Eonil

Generates RPC interfaces for other languages from Rust source code. In other words, this is Rust language as IDL.

Supported Languages & Implementations

• Swift

Swift implementation uses enum to provide module-like namespace.

Support for other languages will be added when I need it.

Design Choices

• This produces interfaces for out-of-process call. This means everything is passed by copy, and peers do not share anything. In-process calls are harder to design and stable. Maybe later.
• As it is out-of-process, everything must be serializable.
• Every intentions will be passed as messages.
• Designed only for bidirectional stream channels.
• Designed only for bidirectional message streams.
• There's no concept of "return values". You have to design your protocol to work without waiting for "return values". This may sounds weird, but your protocol will be simpler and easier to maintain without "return values". See following chapters for details.
• As there's no "return value", all functions are encoded into enum variants.
• No explicit magic number.
• All strings are UTF-8 encoded.
• Uses JSON as default data encoding container. Other encodings can be added, but very unlikely.
• Rust code is "the standard schema". Encoded data will be generated based on Rust code.
• Not all Rust data structures are supported. Only value-semantic and fully cloneable types will be supported.

"No"

• "return values".
• Concept of "function call". There's only "messages".
• Encoding of pointers or references. They're not serializable.
• Fixed sized array. This is indistinguisable with dynamic sized array.

"Not Yet"

• Versioning. Backward compatibility can be implicitly implemented without magic numbers by diffing VCS history.

Designing Protocol without Return Values

This means all of your protocol must be designed in fire & forget basis. Replies must encode its source request so receivers can know how to apply the replies.

Implementations

It's really hard to get fully qualified type paths from Rust compiler. I'm not familiar with the compiler, and I abandoned using compiler directly at some point. Helps are welcome. Instead, mgen uses forked rustdoc code which already has a complete type path resolution support. Due to dependencies of rustdoc, whole Rust compiler is added as a dependency and this is unavoidable until Rust compiler provide more convenient facility to query fully qualified type paths.

License

"MIT License". Contributions will become same license.