9 May
                
                    2008
                
            
            
                9 May
                
                '08
                
            
            
            
        
    
                6:04 p.m.
            
        There are many implementations of such things.  Data.Sequence is one.  You
can also make an implementation that has O(1) cons, snoc, and append, but
that's rather tricky and has a large constant factor.
  -- Lennart
On Fri, May 9, 2008 at 3:16 PM, Andrew Coppin 
The function (++) :: [x] -> [x] -> [x] has O(n) complexity.
If somebody were to invent some type that looks like [x] but actually uses some sort of tree rather than a linked list, you should be able to get O(1) concatenation. Has anybody ever implemented such a thing?
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