Golf macro

Author: Jules-Bertholet

library/std/src/thread/local.rs

@@ -137,9 +137,6 @@ impl<T: 'static> fmt::Debug for LocalKey<T> {
 #[unstable(feature = "thread_local_internals", issue = "none")]
 #[rustc_macro_transparency = "semitransparent"]
 pub macro thread_local_process_attrs {
-    // Base case for recursion:
-    ([] [];) => (),
-
     // Separate attributes into `rustc_align_static` and everything else:
 
     // `rustc_align_static` attribute
@@ -219,26 +216,16 @@ pub macro thread_local_process_attrs {
 
     // Delegate to `thread_local_inner` once attributes are fully categorized:
 
-    // process multiple declarations, starting with a `const` one
-    ([$($align_attrs:tt)*] [$($other_attrs:tt)*]; $vis:vis static $name:ident: $t:ty = const $init:block; $($rest:tt)*) => (
-        $crate::thread::local_impl::thread_local_inner!($($other_attrs)* $vis $name, $t, $($align_attrs)*, const $init);
-        $crate::thread::local_impl::thread_local_process_attrs!([] []; $($rest)*);
-    ),
-
-    // handle a single `const` declaration
-    ([$($align_attrs:tt)*] [$($other_attrs:tt)*]; $vis:vis static $name:ident: $t:ty = const $init:block) => (
+    // process `const` declaration and recurse
+    ([$($align_attrs:tt)*] [$($other_attrs:tt)*]; $vis:vis static $name:ident: $t:ty = const $init:block $(; $($($rest:tt)+)?)?) => (
         $crate::thread::local_impl::thread_local_inner!($($other_attrs)* $vis $name, $t, $($align_attrs)*, const $init);
+        $($($crate::thread::local_impl::thread_local_process_attrs!([] []; $($rest)+);)?)?
     ),
 
-    // process multiple declarations, starting with a non-`const` one
-    ([$($align_attrs:tt)*] [$($other_attrs:tt)*]; $vis:vis static $name:ident: $t:ty = $init:expr; $($rest:tt)*) => (
-        $crate::thread::local_impl::thread_local_inner!($($other_attrs)* $vis $name, $t, $($align_attrs)*, $init);
-        $crate::thread::local_impl::thread_local_process_attrs!([] []; $($rest)*);
-    ),
-
-    // handle a single non-`const` declaration
-    ([$($align_attrs:tt)*] [$($other_attrs:tt)*]; $vis:vis static $name:ident: $t:ty = $init:expr) => (
+    // process non-`const` declaration and recurse
+    ([$($align_attrs:tt)*] [$($other_attrs:tt)*]; $vis:vis static $name:ident: $t:ty = $init:expr $(; $($($rest:tt)+)?)?) => (
         $crate::thread::local_impl::thread_local_inner!($($other_attrs)* $vis $name, $t, $($align_attrs)*, $init);
+        $($($crate::thread::local_impl::thread_local_process_attrs!([] []; $($rest)+);)?)?
     ),
 }
 
@@ -292,8 +279,10 @@ pub macro thread_local_process_attrs {
 #[cfg_attr(not(test), rustc_diagnostic_item = "thread_local_macro")]
 #[allow_internal_unstable(thread_local_internals)]
 macro_rules! thread_local {
-    ($($tt:tt)*) => {
-        $crate::thread::local_impl::thread_local_process_attrs!([] []; $($tt)*);
+    () => {};
+
+    ($($tt:tt)+) => {
+        $crate::thread::local_impl::thread_local_process_attrs!([] []; $($tt)+);
     };
 }