From 2327b213e2a4a82e9f1cfd66559441e2ae7fae54 Mon Sep 17 00:00:00 2001
From: Drew Stone <drewstone329@gmail.com>
Date: Fri, 30 Nov 2018 18:26:24 +0200
Subject: [PATCH] Implement macro for session change trait over arbitrary
tuples (limit 19) (#1177)
* Implement macro for session change trait
* Consolidate tuple macro into one
---
substrate/srml/session/src/lib.rs | 33 +++++++++++++++++++++++--------
1 file changed, 25 insertions(+), 8 deletions(-)
diff --git a/substrate/srml/session/src/lib.rs b/substrate/srml/session/src/lib.rs
index 43eeaaad501..21bc04edb98 100644
--- a/substrate/srml/session/src/lib.rs
+++ b/substrate/srml/session/src/lib.rs
@@ -51,19 +51,36 @@ pub trait OnSessionChange<T> {
fn on_session_change(time_elapsed: T, should_reward: bool);
}
-impl<T> OnSessionChange<T> for () {
- fn on_session_change(_: T, _: bool) {}
+macro_rules! for_each_tuple {
+ ($m:ident) => {
+ for_each_tuple! { @IMPL $m !! A, B, C, D, E, F, G, H, I, J, K, L, M, N, O, P, Q, R, S, }
+ };
+ (@IMPL $m:ident !!) => { $m! { } };
+ (@IMPL $m:ident !! $h:ident, $($t:ident,)*) => {
+ $m! { $h $($t)* }
+ for_each_tuple! { @IMPL $m !! $($t,)* }
+ }
}
-impl<T, A, B> OnSessionChange<T> for (A, B)
- where T: Clone, A: OnSessionChange<T>, B: OnSessionChange<T>
-{
- fn on_session_change(time_elapsed: T, should_reward: bool) {
- A::on_session_change(time_elapsed.clone(), should_reward);
- B::on_session_change(time_elapsed, should_reward);
+macro_rules! impl_session_change {
+ () => (
+ impl<T> OnSessionChange<T> for () {
+ fn on_session_change(_: T, _: bool) {}
+ }
+ );
+
+ ( $($t:ident)* ) => {
+ impl<T: Clone, $($t: OnSessionChange<T>),*> OnSessionChange<T> for ($($t,)*) {
+ fn on_session_change(time_elapsed: T, should_reward: bool) {
+ $($t::on_session_change(time_elapsed.clone(), should_reward);)*
+ }
+ }
}
}
+for_each_tuple!(impl_session_change);
+
+
pub trait Trait: timestamp::Trait {
type ConvertAccountIdToSessionKey: Convert<Self::AccountId, Self::SessionKey>;
type OnSessionChange: OnSessionChange<Self::Moment>;
--
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