optionable_codegen

The relevant main crate is optionable. The docs can be found there.

Purpose

This code generation proc_macro2 library serves two purposes:

• Used by optionable_derive to implement the #[derive(Optionable)]-macro re-exported by optionable.
• Used by the bin/codegen.rs crate to support generating Optionable-implementations for external packages. Due to the orphan rule the generated code has to be added to the Optionable-package (PRs welcome).

It has to be a separate crate from optionable_derive as the proc-macro crates can't export its non-macro functions (even the proc_macro2 ones) for the usage by the codegen part.

Limitations

The codegen logic is at the moment very simple and can only handle very minimalistic input rust types that basically only contain mod, struct and enum. Additional declarations are not an issue if it is ok to simply ignore them.