From 4c2ce050de371e56913683b9fea61c65d341ba72 Mon Sep 17 00:00:00 2001
From: Rob Rix <rob.rix@me.com>
Date: Sat, 9 Sep 2017 15:52:33 +0100
Subject: [PATCH] Define a metavariable type.

---
 src/Diff.hs | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/src/Diff.hs b/src/Diff.hs
index 732f0ca94..178b627c7 100644
--- a/src/Diff.hs
+++ b/src/Diff.hs
@@ -20,6 +20,9 @@ import Text.Show
 -- | An annotated series of patches of terms.
 newtype Diff syntax ann = Diff { unDiff :: DiffF syntax ann (Diff syntax ann) }
 
+newtype MetaVar = MetaVar { unMetaVar :: String }
+  deriving (Eq, Ord, Show)
+
 data DiffF syntax ann recur
   = Copy (Both ann) (syntax recur)
   | Patch (Patch (Term syntax ann))