-% -----------------------------------------------------------------------------
-% $Id: Base.lhs,v 1.8 2002/04/24 16:10:21 simonmar Exp $
-%
-% (c) The University of Glasgow, 1992-2002
-%
\section[GHC.Base]{Module @GHC.Base@}
-
The overall structure of the GHC Prelude is a bit tricky.
a) We want to avoid "orphan modules", i.e. ones with instance
Other Prelude modules are much easier with fewer complex dependencies.
-
\begin{code}
{-# OPTIONS -fno-implicit-prelude #-}
+-----------------------------------------------------------------------------
+-- |
+-- Module : GHC.Base
+-- Copyright : (c) The University of Glasgow, 1992-2002
+-- License : see libraries/base/LICENSE
+--
+-- Maintainer : cvs-ghc@haskell.org
+-- Stability : internal
+-- Portability : non-portable (GHC extensions)
+--
+-- Basic data types and classes.
+--
+-----------------------------------------------------------------------------
#include "MachDeps.h"
%*********************************************************
\begin{code}
+-- |The 'Bool' type is an enumeration. It is defined with 'False'
+-- first so that the corresponding 'Enum' instance will give @'fromEnum'
+-- False@ the value zero, and @'fromEnum' True@ the value 1.
data Bool = False | True deriving (Eq, Ord)
-- Read in GHC.Read, Show in GHC.Show
-- Boolean functions
-(&&), (||) :: Bool -> Bool -> Bool
+-- | Boolean \"and\"
+(&&) :: Bool -> Bool -> Bool
True && x = x
False && _ = False
+
+-- | Boolean \"or\"
+(||) :: Bool -> Bool -> Bool
True || _ = True
False || x = x
+-- | Boolean \"not\"
not :: Bool -> Bool
not True = False
not False = True
+-- |'otherwise' is defined as the value 'True'; it helps to make
+-- guards more readable. eg.
+--
+-- > f x | x \< 0 = ...
+-- > | otherwise = ...
otherwise :: Bool
otherwise = True
\end{code}
\begin{code}
data Int = I# Int#
+-- ^A fixed-precision integer type with at least the range @[-2^29
+-- .. 2^29-1]@. The exact range for a given implementation can be
+-- determined by using 'minBound' and 'maxBound' from the 'Bounded'
+-- class.
zeroInt, oneInt, twoInt, maxInt, minInt :: Int
zeroInt = I# 0#
\begin{code}
unpackCString# :: Addr# -> [Char]
{-# NOINLINE [1] unpackCString# #-}
-unpackCString# a = unpackCStringList# a
-
-unpackCStringList# :: Addr# -> [Char]
-unpackCStringList# addr
+unpackCString# addr
= unpack 0#
where
unpack nh
{-# RULES
"unpack" [~1] forall a . unpackCString# a = build (unpackFoldrCString# a)
-"unpack-list" [1] forall a . unpackFoldrCString# a (:) [] = unpackCStringList# a
+"unpack-list" [1] forall a . unpackFoldrCString# a (:) [] = unpackCString# a
"unpack-append" forall a n . unpackFoldrCString# a (:) n = unpackAppendCString# a n
--- There's a built-in rule (in GHC.Rules.lhs) for
+-- There's a built-in rule (in PrelRules.lhs) for
-- unpackFoldr "foo" c (unpackFoldr "baz" c n) = unpackFoldr "foobaz" c n
#-}