[project @ 2002-05-10 08:58:34 by simonmar]

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

diff --git a/Text/ParserCombinators/ReadPrec.lhs b/Text/ParserCombinators/ReadPrec.lhs
deleted file mode 100644 (file)
index dcfef79..0000000
--- a/Text/ParserCombinators/ReadPrec.lhs
+++ /dev/null
@@ -1,163 +0,0 @@
-% ----------------------------------------------------------------
-% $Id: ReadPrec.lhs
-%
-% (c) The University of Glasgow, 1994-2000
-%
-
-\begin{code}
-{-# OPTIONS -fno-implicit-prelude #-}
-
-module Text.ParserCombinators.ReadPrec
-  ( ReadPrec      -- :: * -> *; instance Functor, Monad, MonadPlus
-  
-  -- precedences
-  , 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
-
-  -- 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
-  )
- where
-
-
-import Text.ParserCombinators.ReadP
-  ( ReadP
-  , readP_to_S
-  , readS_to_P
-  )
-
-import qualified Text.ParserCombinators.ReadP as ReadP
-  ( get
-  , look
-  , (+++)
-  , pfail
-  , choice
-  )
-
-import Control.Monad( MonadPlus(..) )
-import GHC.Num( Num(..) )
-import GHC.Base
-\end{code}
-
-
-%*********************************************************
-%*                                                     *
-\subsection{The readPrec type}
-%*                                                     *
-%*********************************************************
-
-\begin{code}
-newtype ReadPrec a = P { unP :: Prec -> ReadP a }
-
--- Functor, Monad, MonadPlus
-
-instance Functor ReadPrec where
-  fmap h (P f) = P (\n -> fmap h (f n))
-
-instance Monad ReadPrec where
-  return x  = P (\_ -> return x)
-  fail s    = P (\_ -> fail s)
-  P f >>= k = P (\n -> do a <- f n; let P f' = k a in f' n)
-  
-instance MonadPlus ReadPrec where
-  mzero = pfail
-  mplus = (+++)
-
--- precedences
-  
-type Prec = Int
-
-minPrec :: Prec
-minPrec = 0
-\end{code}
-
-
-%*********************************************************
-%*                                                     *
-\subsection{Operations over ReadPrec
-%*                                                     *
-%*********************************************************
-
-\begin{code}
-lift :: ReadP a -> ReadPrec a
-lift m = P (\_ -> m)
-
-step :: ReadPrec a -> ReadPrec a
--- 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
-reset (P f) = P (\n -> f minPrec)
-
-prec :: Prec -> ReadPrec a -> ReadPrec a
--- (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
-prec n (P f) = P (\c -> if c <= n then f n else ReadP.pfail)
-\end{code}
-
-%*********************************************************
-%*                                                     *
-\subsection{Derived operations}
-%*                                                     *
-%*********************************************************
-
-\begin{code}
-get :: ReadPrec Char
-get = lift ReadP.get
-
-look :: ReadPrec String
-look = lift ReadP.look
-
-(+++) :: ReadPrec a -> ReadPrec a -> ReadPrec a
-P f1 +++ P f2 = P (\n -> f1 n ReadP.+++ f2 n)
-
-pfail :: ReadPrec a
-pfail = lift ReadP.pfail
-
-choice :: [ReadPrec a] -> ReadPrec a
-choice ps = foldr (+++) pfail ps
-\end{code}
-
-
-%*********************************************************
-%*                                                     *
-\subsection{Converting between ReadPrec and ReadS
-%*                                                     *
-%*********************************************************
-
-\begin{code}
--- We define a local version of ReadS here,
--- because its "real" definition site is in GHC.Read
-type ReadS a = String -> [(a,String)]
-
-readPrec_to_P :: ReadPrec a -> (Int -> ReadP a)
-readPrec_to_P (P f) = f
-
-readP_to_Prec :: (Int -> ReadP a) -> ReadPrec a
-readP_to_Prec f = P f
-
-readPrec_to_S :: ReadPrec a -> (Int -> ReadS a)
-readPrec_to_S (P f) n = readP_to_S (f n)
-
-readS_to_Prec :: (Int -> ReadS a) -> ReadPrec a
-readS_to_Prec f = P (\n -> readS_to_P (f n))
-\end{code}