12 Jul
2011
12 Jul
'11
10:43 p.m.
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'. [1] http://www.soi.city.ac.uk/~ross/papers/notation.pdf