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%   Frown --- An LALR(k) parser generator for Haskell 98                      %
%   Copyright (C) 2001-2005 Ralf Hinze                                        %
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%   Email:      Ralf Hinze <ralf@cs.uni-bonn.de>                              %
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%   Paper mail: Dr. Ralf Hinze                                                %
%               Institut für Informatik III                                   %
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> module Uniq			(  unique, uniqueBy
>				)
> where

%-------------------------------------------------------------------------------
\section{Unique}
%-------------------------------------------------------------------------------

> uniqueBy			:: (a -> a -> Bool) -> [a] -> [a]
> uniqueBy _ []			=  []
> uniqueBy _ [a]		=  [a]
> uniqueBy (==) (a : x@(b :_ ))
>     | a == b	                =  uniqueBy (==) x
>     | otherwise	        =  a : uniqueBy (==) x

> unique			:: Eq a => [a] -> [a]
> unique			=  uniqueBy (==)
