From: Ian Jackson <ijackson@chiark.greenend.org.uk>
Date: Sun, 2 May 2021 21:11:42 +0000 (+0100)
Subject: if_let: Provide a cardboard cutout version for basic struct variants
X-Git-Tag: otter-0.6.0~468
X-Git-Url: https://www.chiark.greenend.org.uk/ucgi/~ianmdlvl/git?a=commitdiff_plain;h=e10daa1e5b331e4bdd3017d6bafff5172db7a789;p=otter.git

if_let: Provide a cardboard cutout version for basic struct variants

Signed-off-by: Ian Jackson <ijackson@chiark.greenend.org.uk>
---

diff --git a/base/misc.rs b/base/misc.rs
index 7ee1c6f5..c6bbe061 100644
--- a/base/misc.rs
+++ b/base/misc.rs
@@ -75,4 +75,12 @@ macro_rules! if_let {
       _ => { $($otherwise)* },
     };
   };
+  { $($variant:ident)::+ {$binding:ident} = $input:expr;
+    else $($otherwise:tt)*
+  } => {
+    let $binding = match $input {
+      $($variant)::+ { $binding } => $binding,
+      _ => { $($otherwise)* },
+    };
+  };
 }