Document `{, }' subexpressions in eqn.7.

1 files changed, 1 insertions, 0 deletions

diff --git a/eqn.7 b/eqn.7
index c11e7b14..c9c2e993 100644
--- a/eqn.7
+++ b/eqn.7
@@ -63,6 +63,7 @@ The equation grammar is as follows:
 .Bd -literal -offset indent
 eqn     : box | eqn box
 box     : text
+	| { eqn }
         | DEFINE text text
         | SET text text
         | UNDEF text