From a0f2aba67a3f4aae177dee01e17aec85cfab3595 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Eric=20F=C3=B6rster?= <efoerster@users.noreply.github.com>
Date: Wed, 1 May 2019 14:10:32 +0200
Subject: [PATCH] Add macro to combine features with optional values

---
 src/feature.rs | 17 +++++++++++++++++
 1 file changed, 17 insertions(+)

diff --git a/src/feature.rs b/src/feature.rs
index 4477aa65..180d5641 100644
--- a/src/feature.rs
+++ b/src/feature.rs
@@ -32,6 +32,23 @@ macro_rules! concat_feature {
     }};
 }
 
+#[macro_export]
+macro_rules! choice_feature {
+    ($request:expr) => {
+        None
+    };
+    ($request:expr, $provider:tt, $($providers:tt),*) => {{
+        $(
+            let value = await!($provider::execute($request));
+            if value.is_some() {
+                value
+            } else {
+                choice_feature!($request, $(providers),*)
+            }
+        )+
+    }};
+}
+
 #[cfg(test)]
 use lsp_types::*;