Here's what Edward has to say about his talk (I wanted to include that into
the announcement, but it did not quite work out):
I plan to give an introduction to the
lens<http://hackage.haskell.org/package/lens>library. My current plan
is for the talk to be broken into two parts, so if
there is some kind of refreshment or food break, there should be a pretty
good point in the middle to insert it.
First, I want to give a fairly general introduction to the concept of a
Lens, and some of the easier refinements of the idea used by the lens
library, such a Traversal, Fold, Getter, Setter. It would be helpful for
the audience to have passing familiarity with Applicative, Foldable and
Traversable from base, and maybe a rough understanding of Rank2Types, but
pretty much everything else that I need I'll be introducing, including the
concept of a lens and the lens laws.
Second, I'll show how deep the rabbit hole goes, by showing off some of the
more interesting bits of the library, such as the generalization of Neil
Mitchell's uniplate to work with arbitrary Traversals (simultaneously
gaining generality, ease of use, and speed) and some nice examples of how
we can use the type-safe Traversal-based Zippers from lens as well. This
part will admittedly be a lot of material presented in a fairly short time.
If I had to hazard a guess based on how long the talk took at Boston
Haskell, it may run about an hour and a half, with the first segment being
somewhere between a half hour and 45 minutes.
TL;DR I plan to give a crash course on lenses and traversals covering how
they work in practice and how you can use them to clean up code along with
some non-obvious applications.
Cheers,
Ivan
On Wed, Oct 10, 2012 at 9:51 AM, Ivan Tarasov <ivan.tara...@gmail.com>wrote:
> Hello, fellow Haskell enthusiasts,
> This month we have quite a treat, with Edward Kmett making a talk about
> Lenses and Traversals. This is a very important topic, and our last month's
> guest Russell O'Connor strongly urged everybody to come and listen to this
> talk. There is suggested reading for the talk: "The Essence of the
> Iterator Patttern"<http://www.cs.ox.ac.uk/jeremy.gibbons/publications/iterator.pdf>paper by Jeremy Gibbons and Bruno C. d. S. Oliveira, please take a look at
> it if you have a chance.
> Our venue this time is Google office in San Francisco SoMa:
> 345 Spear Str, San Francisco
> Contact phone (mine): 650-762-6644.
> Host: Satnam Singh, sat...@raintown.org, cell: 408 656 4590. Please
> contact Satnam if you have questions about the venue or need help with the
> venue.
> Please arrive a little bit earlier, so that we could start at 7pm. Also if
> you arrive around 6:30pm, you can get some dinner at
> We may try to set up the video feed through Google Hangout (hangout link<http://goo.gl/19Fkz>,
> also available through our calendar <http://goo.gl/EWDUt>), however
> please don't rely on it and try to visit the meeting in person if possible.
> If you are going to be joining the hangout, please mute your microphone
> before you join.
> Some people will be going from the South Bay and East Bay to the meeting
> and back, so there's a possibility of carpooling. Also, it's very easy to
> get to the venue from the 4th & King Caltrain Station: check Google Maps
> for directions, it's also not a very long walk from Caltrain. Please send
> me a message if you need help figuring out transportation. If you are
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> Cheers,
> Ivan
