[PATCH 1/4] rust: macros: extend custom `quote!()` macro

[Jesung Yang <y.j3ms.n@gmail.com>]

Implement the `ToTokens` trait for `&T` where `T` implements `ToTokens`.
This allows users to use the `quote!()` macro with references directly,
avoiding the need to clone values.

Extend the `quote_spanned!()` macro to support additional punctuation
tokens: `->`, `<`, `>`, and `==`. This symbols are commonly needed when
dealing with functions, generic bounds, and equality comparisons.

Signed-off-by: Jesung Yang <y.j3ms.n@gmail.com>
---
 rust/macros/quote.rs | 36 ++++++++++++++++++++++++++++++++++++
 1 file changed, 36 insertions(+)

diff --git a/rust/macros/quote.rs b/rust/macros/quote.rs
index 92cacc4067c9..24764b04a07d 100644
--- a/rust/macros/quote.rs
+++ b/rust/macros/quote.rs
@@ -7,6 +7,12 @@ pub(crate) trait ToTokens {
     fn to_tokens(&self, tokens: &mut TokenStream);
 }
 
+impl<T: ToTokens> ToTokens for &T {
+    fn to_tokens(&self, tokens: &mut TokenStream) {
+        (*self).to_tokens(tokens);
+    }
+}
+
 impl<T: ToTokens> ToTokens for Option<T> {
     fn to_tokens(&self, tokens: &mut TokenStream) {
         if let Some(v) = self {
@@ -144,6 +150,36 @@ macro_rules! quote_spanned {
         ));
         quote_spanned!(@proc $v $span $($tt)*);
     };
+    (@proc $v:ident $span:ident -> $($tt:tt)*) => {
+        $v.push(::proc_macro::TokenTree::Punct(
+                ::proc_macro::Punct::new('-', ::proc_macro::Spacing::Joint)
+        ));
+        $v.push(::proc_macro::TokenTree::Punct(
+                ::proc_macro::Punct::new('>', ::proc_macro::Spacing::Alone)
+        ));
+        quote_spanned!(@proc $v $span $($tt)*);
+    };
+    (@proc $v:ident $span:ident < $($tt:tt)*) => {
+        $v.push(::proc_macro::TokenTree::Punct(
+                ::proc_macro::Punct::new('<', ::proc_macro::Spacing::Alone)
+        ));
+        quote_spanned!(@proc $v $span $($tt)*);
+    };
+    (@proc $v:ident $span:ident > $($tt:tt)*) => {
+        $v.push(::proc_macro::TokenTree::Punct(
+                ::proc_macro::Punct::new('>', ::proc_macro::Spacing::Alone)
+        ));
+        quote_spanned!(@proc $v $span $($tt)*);
+    };
+    (@proc $v:ident $span:ident == $($tt:tt)*) => {
+        $v.push(::proc_macro::TokenTree::Punct(
+                ::proc_macro::Punct::new('=', ::proc_macro::Spacing::Joint)
+        ));
+        $v.push(::proc_macro::TokenTree::Punct(
+                ::proc_macro::Punct::new('=', ::proc_macro::Spacing::Alone)
+        ));
+        quote_spanned!(@proc $v $span $($tt)*);
+    };
     (@proc $v:ident $span:ident = $($tt:tt)*) => {
         $v.push(::proc_macro::TokenTree::Punct(
                 ::proc_macro::Punct::new('=', ::proc_macro::Spacing::Alone)
-- 
2.39.5