[Haskell-beginners] homogeneous value list
tom.davie at gmail.com
Fri Mar 12 09:28:29 EST 2010
On 12 Mar 2010, at 14:25, Salil Wadnerkar wrote:
> On Fri, Mar 12, 2010 at 10:21 PM, Ozgur Akgun <ozgurakgun at gmail.com> wrote:
>> Another boring variant from me then.
>> isHomogeneous xs = all (first==) xs
>> where first = head xs
> head xs
> give an exception on an empty list?
An error, and only if it's evaluated. Lazy evaluation means it's not evaluated here.
Of course another non-strict algorithm *might* evaluate head xs here, so this version won't work in all possible Haskell implementations, only the current ones which use lazy evaluation.
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