Fielded Enum Question

[tylerhartwig]

Hi,

I'm trying to use csbindgen with Automerge's C FFI compatibility: https://github.com/automerge/automerge

I've noticed in the issues that fielded enums are not supported for generation.

What is the recommended path forward here? how would csbindgen handle a basic Result type in Rust? (the issue I'm running into is with a custom enum called AMresult in Automerge).

[github-actions]

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[Skgland]

I think the way forward would be to desugar enums according to RFC 2195.

Enum with

• #[repr(u*/i*)] would desugar into a union¹ of tag prefixed structs.
• #[repr(C, u*/i*)] would desugar into struct with two fields.
  • an enum for the tag and
  • a union¹ of structs for the variants

Footnotes

1. https://learn.microsoft.com/en-us/dotnet/csharp/advanced-topics/reflection-and-attributes/how-to-create-a-c-cpp-union-by-using-attributes ↩ ↩²