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Add intercalate to Data.List (ticket #971)
author
Josef Svenningsson
<josef.svenningsson@gmail.com>
Thu, 2 Nov 2006 12:20:52 +0000
(12:20 +0000)
committer
Josef Svenningsson
<josef.svenningsson@gmail.com>
Thu, 2 Nov 2006 12:20:52 +0000
(12:20 +0000)
Data/List.hs
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diff --git
a/Data/List.hs
b/Data/List.hs
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7c3cede
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b006b29
100644
(file)
--- a/
Data/List.hs
+++ b/
Data/List.hs
@@
-35,6
+35,7
@@
module Data.List
, reverse -- :: [a] -> [a]
, intersperse -- :: a -> [a] -> [a]
, reverse -- :: [a] -> [a]
, intersperse -- :: a -> [a] -> [a]
+ , intercalate -- :: [a] -> [[a]] -> [a]
, transpose -- :: [[a]] -> [[a]]
-- * Reducing lists (folds)
, transpose -- :: [[a]] -> [[a]]
-- * Reducing lists (folds)
@@
-396,6
+397,12
@@
intersperse _ [] = []
intersperse _ [x] = [x]
intersperse sep (x:xs) = x : sep : intersperse sep xs
intersperse _ [x] = [x]
intersperse sep (x:xs) = x : sep : intersperse sep xs
+-- | 'intercalate' @xs xss@ is equivalent to @('concat' ('intersperse' xs xss))@.
+-- It inserts the list @xs@ in between the lists in @xss@ and concatenates the
+-- result.
+intercalate :: [a] -> [[a]] -> [a]
+intercalate xs xss = concat (intersperse xs xss)
+
-- | The 'transpose' function transposes the rows and columns of its argument.
-- For example,
--
-- | The 'transpose' function transposes the rows and columns of its argument.
-- For example,
--