Data/Array.hs

    {-# LANGUAGE Trustworthy #-}
    -----------------------------------------------------------------------------
    -- |
    -- Module      :  Data.Array
    -- Copyright   :  (c) The University of Glasgow 2001
    -- License     :  BSD-style (see the file libraries/base/LICENSE)
    --
    -- Maintainer  :  libraries@haskell.org
    -- Stability   :  provisional
    -- Portability :  portable
    --
    -- Basic non-strict arrays.
    --
    -- /Note:/ The "Data.Array.IArray" module provides a more general interface
    -- to immutable arrays: it defines operations with the same names as
    -- those defined below, but with more general types, and also defines
    -- 'Array' instances of the relevant classes.  To use that more general
    -- interface, import "Data.Array.IArray" but not "Data.Array".
    --
    -----------------------------------------------------------------------------

    module Data.Array (
        -- * Immutable non-strict arrays
        -- $intro
        module Data.Ix, -- export all of Ix
        Array,          -- Array type is abstract

        -- * Array construction
        array,          -- :: (Ix a) => (a,a) -> [(a,b)] -> Array a b
        listArray,      -- :: (Ix a) => (a,a) -> [b] -> Array a b
        accumArray,     -- :: (Ix a) => (b -> c -> b) -> b -> (a,a) -> [(a,c)] -> Array a b
        -- * Accessing arrays
        (!),            -- :: (Ix a) => Array a b -> a -> b
        bounds,         -- :: (Ix a) => Array a b -> (a,a)
        indices,        -- :: (Ix a) => Array a b -> [a]
        elems,          -- :: (Ix a) => Array a b -> [b]
        assocs,         -- :: (Ix a) => Array a b -> [(a,b)]
        -- * Incremental array updates
        (//),           -- :: (Ix a) => Array a b -> [(a,b)] -> Array a b
        accum,          -- :: (Ix a) => (b -> c -> b) -> Array a b -> [(a,c)] -> Array a b
        -- * Derived arrays
        ixmap,          -- :: (Ix a, Ix b) => (a,a) -> (a -> b) -> Array b c -> Array a b

        -- Array instances:
        --
        --   Ix a => Functor (Array a)
        --   (Ix a, Eq b)  => Eq   (Array a b)
        --   (Ix a, Ord b) => Ord  (Array a b)
        --   (Ix a, Show a, Show b) => Show (Array a b)
        --   (Ix a, Read a, Read b) => Read (Array a b)
        --

        -- Implementation checked wrt. Haskell 98 lib report, 1/99.
      ) where

    import Data.Ix
    import Data.Typeable ()

    import GHC.Arr  -- Most of the hard work is done here

    {- $intro
    Haskell provides indexable /arrays/, which may be thought of as functions
    whose domains are isomorphic to contiguous subsets of the integers.
    Functions restricted in this way can be implemented efficiently;
    in particular, a programmer may reasonably expect rapid access to
    the components.  To ensure the possibility of such an implementation,
    arrays are treated as data, not as general functions.

    Since most array functions involve the class 'Ix', this module is exported
    from "Data.Array" so that modules need not import both "Data.Array" and
    "Data.Ix".
    -}