Data.Functor module naming?

Ross Paterson ross at
Mon Nov 8 18:44:01 EST 2010

On Mon, Nov 08, 2010 at 11:37:38PM +0000, Duncan Coutts wrote:
> On 8 November 2010 22:55, Daniel Peebles <pumpkingod at> wrote:
> > Hi all,
> > I was wondering if anyone knew the rationale behind naming the module
> > Data.Functor instead of the (seemingly) more natural Control.Functor.
> I'm not sure if it answers your question, but it goes along with
> Applicative living under the Data, not Control hierarchy.

Actually there is Control.Applicative, but Data.Foldable and

I guess the answer is that functors include control-like things like
monads and applicative functors, but also data-like things like trees
and maps.

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