Ticket #1182: 0001-Make-splitAt-conform-to-Haskell-98-2010-fixes-1182_2010.patch

File 0001-Make-splitAt-conform-to-Haskell-98-2010-fixes-1182_2010.patch, 2.1 KB (added by michalt, 2 years ago)

Patch for haskell2010.

  • Data/List.hs 

    From 5f2cd1328b3ae36bdf4750a66df39265b747bd34 Mon Sep 17 00:00:00 2001
From: Michal Terepeta <michal.terepeta@gmail.com>
Date: Mon, 20 Jun 2011 21:06:20 +0200
Subject: [PATCH] Make splitAt conform to Haskell 98/2010 (fixes #1182).

---
 Data/List.hs |    2 +-
 Prelude.hs   |   23 ++++++++++++++++++++++-
 2 files changed, 23 insertions(+), 2 deletions(-)

diff --git a/Data/List.hs b/Data/List.hs
index 8258663..78f633f 100644
    a b  
    181181   , genericReplicate  -- :: (Integral a) => a -> b -> [b] 
    182182 
    183183  ) where 
    184 import "base" Data.List 
     184import "base" Data.List hiding ( splitAt ) 

  • Prelude.hs 

    diff --git a/Prelude.hs b/Prelude.hs
index 9be6ccf..72e53d2 100644
    a b  
    137137import "base" Control.Monad 
    138138import "base" System.IO 
    139139import "base" System.IO.Error (IOError, ioError, userError) 
    140 import "base" Data.List 
     140import "base" Data.List hiding ( splitAt ) 
    141141import "base" Data.Either 
    142142import "base" Data.Maybe 
    143143import "base" Data.Tuple 
    … …  
    216216gcd x y         = GHC.Real.gcd x y 
    217217#endif 
    218218 
     219#ifndef __HUGS__ 
     220-- The GHC's version of 'splitAt' is too strict in 'n' compared to 
     221-- Haskell98/2010 version. Ticket #1182. 
     222 
     223-- | 'splitAt' @n xs@ returns a tuple where first element is @xs@ prefix of 
     224-- length @n@ and second element is the remainder of the list: 
     225-- 
     226-- > splitAt 6 "Hello World!" == ("Hello ","World!") 
     227-- > splitAt 3 [1,2,3,4,5] == ([1,2,3],[4,5]) 
     228-- > splitAt 1 [1,2,3] == ([1],[2,3]) 
     229-- > splitAt 3 [1,2,3] == ([1,2,3],[]) 
     230-- > splitAt 4 [1,2,3] == ([1,2,3],[]) 
     231-- > splitAt 0 [1,2,3] == ([],[1,2,3]) 
     232-- > splitAt (-1) [1,2,3] == ([],[1,2,3]) 
     233-- 
     234-- It is equivalent to @('take' n xs, 'drop' n xs)@. 
     235-- 'splitAt' is an instance of the more general 'Data.List.genericSplitAt', 
     236-- in which @n@ may be of any integral type. 
     237splitAt                :: Int -> [a] -> ([a],[a]) 
     238splitAt n xs           =  (take n xs, drop n xs) 
     239#endif