Proc Macro Entry Points

zyn provides attribute macros that replace #[proc_macro_derive] and #[proc_macro_attribute] with a declarative, template-first workflow.

• #[zyn::derive] — replaces #[proc_macro_derive]
• #[zyn::attribute] — replaces #[proc_macro_attribute]

What’s Generated

Both macros generate a complete proc macro entry point:

1. Input parsing — DeriveInput for derives, Item for attributes, wrapped in zyn::Input
2. input binding — available in scope for zyn! and element extractors
3. Extractor resolution — #[zyn(input)] parameters are resolved via FromInput
4. Diagnostic macros — error!, warn!, note!, help!, bail! (same as #[zyn::element])
5. Return type conversion — your proc_macro2::TokenStream is automatically converted to proc_macro::TokenStream

You write a function that returns zyn::TokenStream. The macro handles everything else.