On Tue, Jul 12, 2011 at 6:55 PM, Felipe Almeida Lessa
<felipe.lessa@gmail.com> wrote:
ArrowChoice's (+++) documentation [1] says that "this is in general
not a functor" [1]. What does it mean for (+++) to be or not to be a
functor?
The same note is made for (***). If you review Ross Patterson's paper [1], you'll see a note: "Note that *** does not in general preserve composition; for example, the order in which effects occur is significant." I expect the note in Control.Arrow is an oblique reference to this 'fact'.