Rewrite of the IO library, including Unicode support
[packages/base.git] / Prelude.hs
1 {-# OPTIONS_GHC -XNoImplicitPrelude #-}
2 -----------------------------------------------------------------------------
3 -- |
4 -- Module : Prelude
5 -- Copyright : (c) The University of Glasgow 2001
6 -- License : BSD-style (see the file libraries/base/LICENSE)
7 --
8 -- Maintainer : libraries@haskell.org
9 -- Stability : stable
10 -- Portability : portable
11 --
12 -- The Prelude: a standard module imported by default into all Haskell
13 -- modules. For more documentation, see the Haskell 98 Report
14 -- <http://www.haskell.org/onlinereport/>.
15 --
16 -----------------------------------------------------------------------------
17
18 module Prelude (
19
20 -- * Standard types, classes and related functions
21
22 -- ** Basic data types
23 Bool(False, True),
24 (&&), (||), not, otherwise,
25
26 Maybe(Nothing, Just),
27 maybe,
28
29 Either(Left, Right),
30 either,
31
32 Ordering(LT, EQ, GT),
33 Char, String,
34
35 -- *** Tuples
36 fst, snd, curry, uncurry,
37
38 #if defined(__NHC__)
39 []((:), []), -- Not legal Haskell 98;
40 -- ... available through built-in syntax
41 module Data.Tuple, -- Includes tuple types
42 ()(..), -- Not legal Haskell 98
43 (->), -- ... available through built-in syntax
44 #endif
45 #ifdef __HUGS__
46 (:), -- Not legal Haskell 98
47 #endif
48
49 -- ** Basic type classes
50 Eq((==), (/=)),
51 Ord(compare, (<), (<=), (>=), (>), max, min),
52 Enum(succ, pred, toEnum, fromEnum, enumFrom, enumFromThen,
53 enumFromTo, enumFromThenTo),
54 Bounded(minBound, maxBound),
55
56 -- ** Numbers
57
58 -- *** Numeric types
59 Int, Integer, Float, Double,
60 Rational,
61
62 -- *** Numeric type classes
63 Num((+), (-), (*), negate, abs, signum, fromInteger),
64 Real(toRational),
65 Integral(quot, rem, div, mod, quotRem, divMod, toInteger),
66 Fractional((/), recip, fromRational),
67 Floating(pi, exp, log, sqrt, (**), logBase, sin, cos, tan,
68 asin, acos, atan, sinh, cosh, tanh, asinh, acosh, atanh),
69 RealFrac(properFraction, truncate, round, ceiling, floor),
70 RealFloat(floatRadix, floatDigits, floatRange, decodeFloat,
71 encodeFloat, exponent, significand, scaleFloat, isNaN,
72 isInfinite, isDenormalized, isIEEE, isNegativeZero, atan2),
73
74 -- *** Numeric functions
75 subtract, even, odd, gcd, lcm, (^), (^^),
76 fromIntegral, realToFrac,
77
78 -- ** Monads and functors
79 Monad((>>=), (>>), return, fail),
80 Functor(fmap),
81 mapM, mapM_, sequence, sequence_, (=<<),
82
83 -- ** Miscellaneous functions
84 id, const, (.), flip, ($), until,
85 asTypeOf, error, undefined,
86 seq, ($!),
87
88 -- * List operations
89 map, (++), filter,
90 head, last, tail, init, null, length, (!!),
91 reverse,
92 -- ** Reducing lists (folds)
93 foldl, foldl1, foldr, foldr1,
94 -- *** Special folds
95 and, or, any, all,
96 sum, product,
97 concat, concatMap,
98 maximum, minimum,
99 -- ** Building lists
100 -- *** Scans
101 scanl, scanl1, scanr, scanr1,
102 -- *** Infinite lists
103 iterate, repeat, replicate, cycle,
104 -- ** Sublists
105 take, drop, splitAt, takeWhile, dropWhile, span, break,
106 -- ** Searching lists
107 elem, notElem, lookup,
108 -- ** Zipping and unzipping lists
109 zip, zip3, zipWith, zipWith3, unzip, unzip3,
110 -- ** Functions on strings
111 lines, words, unlines, unwords,
112
113 -- * Converting to and from @String@
114 -- ** Converting to @String@
115 ShowS,
116 Show(showsPrec, showList, show),
117 shows,
118 showChar, showString, showParen,
119 -- ** Converting from @String@
120 ReadS,
121 Read(readsPrec, readList),
122 reads, readParen, read, lex,
123
124 -- * Basic Input and output
125 IO,
126 -- ** Simple I\/O operations
127 -- All I/O functions defined here are character oriented. The
128 -- treatment of the newline character will vary on different systems.
129 -- For example, two characters of input, return and linefeed, may
130 -- read as a single newline character. These functions cannot be
131 -- used portably for binary I/O.
132 -- *** Output functions
133 putChar,
134 putStr, putStrLn, print,
135 -- *** Input functions
136 getChar,
137 getLine, getContents, interact,
138 -- *** Files
139 FilePath,
140 readFile, writeFile, appendFile, readIO, readLn,
141 -- ** Exception handling in the I\/O monad
142 IOError, ioError, userError, catch
143
144 ) where
145
146 #ifndef __HUGS__
147 import Control.Monad
148 import System.IO
149 import System.IO.Error
150 import Data.List
151 import Data.Either
152 import Data.Maybe
153 import Data.Tuple
154 #endif
155
156 #ifdef __GLASGOW_HASKELL__
157 import GHC.Base
158 import GHC.IO
159 import GHC.IO.Exception
160 import Text.Read
161 import GHC.Enum
162 import GHC.Num
163 import GHC.Real
164 import GHC.Float
165 import GHC.Show
166 import GHC.Err ( error, undefined )
167 #endif
168
169 #ifdef __HUGS__
170 import Hugs.Prelude
171 #endif
172
173 #ifndef __HUGS__
174 infixr 0 $!
175
176 -- -----------------------------------------------------------------------------
177 -- Miscellaneous functions
178
179 -- | Strict (call-by-value) application, defined in terms of 'seq'.
180 ($!) :: (a -> b) -> a -> b
181 f $! x = x `seq` f x
182 #endif
183
184 #ifdef __HADDOCK__
185 -- | The value of @'seq' a b@ is bottom if @a@ is bottom, and otherwise
186 -- equal to @b@. 'seq' is usually introduced to improve performance by
187 -- avoiding unneeded laziness.
188 seq :: a -> b -> b
189 seq _ y = y
190 #endif