Crate proc_macro_nested
source ·Expand description
Support for nested invocations of proc-macro-hack expression macros.
By default, macros defined through proc-macro-hack do not support nested invocations, i.e. the code emitted by a proc-macro-hack macro invocation cannot contain recursive calls to the same proc-macro-hack macro nor calls to any other proc-macro-hack macros.
This crate provides opt-in support for such nested invocations.
To make a macro callable recursively, add a dependency on this crate from
your declaration crate and update the #[proc_macro_hack]
re-export as
follows.
// Before
#[proc_macro_hack]
pub use demo_hack_impl::add_one;
// After
extern crate proc_macro_nested;
#[proc_macro_hack(support_nested)]
pub use demo_hack_impl::add_one;
No change is required within your definition crate, only in the declaration crate.