Document LazyUniqFM

[ghc-hetmet.git] / compiler / utils / LazyUniqFM.lhs

diff --git a/compiler/utils/LazyUniqFM.lhs b/compiler/utils/LazyUniqFM.lhs
index 99be163..709d4e0 100644 (file)
--- a/compiler/utils/LazyUniqFM.lhs
+++ b/compiler/utils/LazyUniqFM.lhs
@@ -13,8 +13,10 @@ Basically, the things need to be in class @Uniquable@, and we use the
 \begin{code}
 {-# OPTIONS -Wall -fno-warn-name-shadowing -Werror #-}
 module LazyUniqFM (
+       -- * Lazy unique-keyed mappings
        UniqFM,         -- abstract type
 
+       -- ** Manipulating those mappings
        emptyUFM,
        unitUFM,
        unitDirectlyUFM,
@@ -177,6 +179,7 @@ ufmToList   :: UniqFM elt -> [(Unique, elt)]
 \begin{code}
 data Lazy a = Lazy { fromLazy :: a }
 
+-- | @UniqFM a@ is a mapping from Unique to @a@ where the element @a@ is evaluated lazily.
 newtype UniqFM ele = MkUniqFM (S.UniqFM (Lazy ele))
 
 instance Outputable a => Outputable (UniqFM a) where