diff --git a/src/Language/Ruby/Syntax.hs b/src/Language/Ruby/Syntax.hs
index 3957c0805..70eb5028b 100644
--- a/src/Language/Ruby/Syntax.hs
+++ b/src/Language/Ruby/Syntax.hs
@@ -115,6 +115,9 @@ type FAlgebra t a = Base t a -> a
 -- | An R-algebra on the base functor of some type 't'.
 type RAlgebra t a = Base t (t, a) -> a
 
+-- | A CV-algebra (Course of Value) on the base functor of some type 't'; an algebra which provides its references upon request.
+type CVAlgebra t a = Base t (Cofree (Base t) a) -> a
+
 -- | Promote an FAlgebra into an RAlgebra (by dropping the original parameter).
 fToR :: Functor (Base t) => FAlgebra t a -> RAlgebra t a
 fToR f = f . fmap snd