Re: [Haskell-cafe] Learn You a Haskell for Great Good - a few doubts

On 3 March 2011 17:59, Karthick Gururaj wrote:

On Thu, Mar 3, 2011 at 11:48 AM, Chris Smith wrote:

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On Thu, 2011-03-03 at 11:39 +0530, Karthick Gururaj wrote:

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What is the "()" type? Does it refer to a tuple? How can tuple be ordered, let alone be enum'd? I tried:

The () type is pronounced "unit".  It is a type with only 1 value, also called () and pronounced "unit".  Since it only has one possible value, it conveys no information at all, and is sometimes used in situations analogous to C's 'void' keyword.

Okay, actually that was a little bit of a lie; () has two "values": () and bottom.  Bottom is the "value" that corresponds to the program hanging in an infinite loop or dying with an error message.  But if you have an actual, honest-to-goodness value that's not bottom, it has to be (). Thanks - is this the same "unit" that accompanies IO in "IO ()" ? In any case, my question is answered since it is not a tuple.

Yes. -- Ivan Lazar Miljenovic Ivan.Miljenovic@gmail.com IvanMiljenovic.wordpress.com