diff --git a/doc/coding_style.mdwn b/doc/coding_style.mdwn
index 1b6c525..10b9832 100644
--- a/doc/coding_style.mdwn
+++ b/doc/coding_style.mdwn
@@ -70,6 +70,14 @@ that line up with the open and close punctuation.
 		, address = "baz"
 		}
 
+Similarly, data structures line up the leading `=` with the following `|`
+
+	data Foo
+		= Bar
+		| Baz
+		| Quux Foo
+		deriving (Eq, Ord)
+
 Module imports are separated into two blocks, one for third-party modules,
 and one for modules that are part of propellor. (Additional blocks can be used
 if it makes sense.)