From 434dd829b3d87b257d86308752a892df66f1017f Mon Sep 17 00:00:00 2001
From: Rob Rix <rob.rix@me.com>
Date: Thu, 21 Dec 2017 10:54:40 -0500
Subject: [PATCH] :memo: the Fresh constructors.

---
 src/Control/Monad/Effect/Fresh.hs | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/src/Control/Monad/Effect/Fresh.hs b/src/Control/Monad/Effect/Fresh.hs
index 051a57177..65542e2c8 100644
--- a/src/Control/Monad/Effect/Fresh.hs
+++ b/src/Control/Monad/Effect/Fresh.hs
@@ -8,8 +8,8 @@ type TName = Int
 
 -- | An effect offering a (resettable) sequence of always-incrementing, and therefore “fresh,” type variables.
 data Fresh a where
-  Reset :: TName -> Fresh ()
-  Fresh :: Fresh TName
+  Reset :: TName -> Fresh () -- ^ Reset the sequence of variable names. Useful to avoid complicated alpha-equivalence comparisons when iteratively recomputing the results of an analysis til convergence.
+  Fresh :: Fresh TName       -- ^ Get a fresh variable name, guaranteed unused since the last reset.
 
 class Monad m => MonadFresh m where
   fresh :: m TName