[Haskell-cafe] Idiomatically using lists

kevin birch kbirch at pobox.com
Mon Jun 4 09:54:41 EDT 2007


Hello all,

I have an implementation question that I hope someone can help out  
with.  Say I have a fixed-size list: [1, 2, 3, 4, 5] that I want to  
treat as circular in a function in order to rotate one of the  
elements n positions.  So rotating the second element 2 positions  
would result in: [1, 3, 4, 2, 5], or rotating the fourth element 2  
positions would result in: [1, 2, 4, 3, 5].  There are two cases: if  
the element can be moved w/o rotating and where the element must be  
inserted into the list at the front.  Is there an idomatic way to  
handle both of these cases in a function?

Thanks,
kevin
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