[project @ 2002-08-30 14:19:18 by simonpj]

[ghc-base.git] / Text / ParserCombinators / ReadPrec.hs

diff --git a/Text/ParserCombinators/ReadPrec.hs b/Text/ParserCombinators/ReadPrec.hs
index bfb4fc2..50cef1e 100644 (file)
--- a/Text/ParserCombinators/ReadPrec.hs
+++ b/Text/ParserCombinators/ReadPrec.hs
@@ -9,33 +9,37 @@
 -- Stability   :  provisional
 -- Portability :  portable
 --
+-- This library defines parser combinators for precedence parsing.
+
 -----------------------------------------------------------------------------
 
 module Text.ParserCombinators.ReadPrec
-  ( ReadPrec      -- :: * -> *; instance Functor, Monad, MonadPlus
+  ( 
+  ReadPrec,      -- :: * -> *; instance Functor, Monad, MonadPlus
   
   -- * Precedences
-  , Prec          -- :: *; = Int
-  , minPrec       -- :: Prec; = 0
+  Prec,          -- :: *; = Int
+  minPrec,       -- :: Prec; = 0
 
-  -- * Primitive operations
-  , lift          -- :: ReadP a -> ReadPrec a
-  , prec          -- :: Prec -> ReadPrec a -> ReadPrec a
-  , step          -- :: ReadPrec a -> ReadPrec a
-  , reset         -- :: ReadPrec a -> ReadPrec a
+  -- * Precedence operations
+  lift,          -- :: ReadP a -> ReadPrec a
+  prec,          -- :: Prec -> ReadPrec a -> ReadPrec a
+  step,          -- :: ReadPrec a -> ReadPrec a
+  reset,         -- :: ReadPrec a -> ReadPrec a
 
   -- * Other operations
-  , get           -- :: ReadPrec Char
-  , look          -- :: ReadPrec String
-  , (+++)         -- :: ReadPrec a -> ReadPrec a -> ReadPrec a
-  , pfail         -- :: ReadPrec a
-  , choice        -- :: [ReadPrec a] -> ReadPrec a
-
-  -- converters
-  , readPrec_to_P -- :: ReadPrec a       -> (Int -> ReadP a)
-  , readP_to_Prec -- :: (Int -> ReadP a) -> ReadPrec a
-  , readPrec_to_S -- :: ReadPrec a       -> (Int -> ReadS a)
-  , readS_to_Prec -- :: (Int -> ReadS a) -> ReadPrec a
+  -- All are based directly on their similarly-naned 'ReadP' counterparts.
+  get,           -- :: ReadPrec Char
+  look,          -- :: ReadPrec String
+  (+++),         -- :: ReadPrec a -> ReadPrec a -> ReadPrec a
+  pfail,         -- :: ReadPrec a
+  choice,        -- :: [ReadPrec a] -> ReadPrec a
+
+  -- * Converters
+  readPrec_to_P, -- :: ReadPrec a       -> (Int -> ReadP a)
+  readP_to_Prec, -- :: (Int -> ReadP a) -> ReadPrec a
+  readPrec_to_S, -- :: ReadPrec a       -> (Int -> ReadS a)
+  readS_to_Prec, -- :: (Int -> ReadS a) -> ReadPrec a
   )
  where
 
@@ -88,21 +92,22 @@ minPrec = 0
 -- Operations over ReadPrec
 
 lift :: ReadP a -> ReadPrec a
+-- ^ Lift a predence-insensitive 'ReadP' to a 'ReadPrec'
 lift m = P (\_ -> m)
 
 step :: ReadPrec a -> ReadPrec a
--- Increases the precedence context by one
+-- ^ Increases the precedence context by one
 step (P f) = P (\n -> f (n+1))
 
 reset :: ReadPrec a -> ReadPrec a
--- Resets the precedence context to zero
+-- ^ Resets the precedence context to zero
 reset (P f) = P (\n -> f minPrec)
 
 prec :: Prec -> ReadPrec a -> ReadPrec a
--- (prec n p) checks that the precedence context is 
+-- ^ @(prec n p)@ checks that the precedence context is 
 --                       less than or equal to n,
---     if not, fails
---     if so, parses p in context n
+--   * if not, fails
+--   * if so, parses p in context n
 prec n (P f) = P (\c -> if c <= n then f n else ReadP.pfail)
 
 -- ---------------------------------------------------------------------------