addressalign-toparrow-leftarrow-rightbackbellblockcalendarcameraccwcheckchevron-downchevron-leftchevron-rightchevron-small-downchevron-small-leftchevron-small-rightchevron-small-upchevron-upcircle-with-checkcircle-with-crosscircle-with-pluscrossdots-three-verticaleditemptyheartexporteye-with-lineeyefacebookfolderfullheartglobegmailgooglegroupshelp-with-circleimageimagesinstagramFill 1linklocation-pinm-swarmSearchmailmessagesminusmoremuplabelShape 3 + Rectangle 1ShapeoutlookpersonJoin Group on CardStartprice-ribbonShapeShapeShapeShapeImported LayersImported LayersImported Layersshieldstartickettrashtriangle-downtriangle-uptwitteruserwarningyahoo and Ur/Web

We have two talks this month on opposite ends of the experience spectrum.

7:00-8:00: Josh Cough/Jacy Cough -

Josh and 13 year old Jacy Cough will demo CodeWorld, "an educational web-based programming environment using a variant of Haskell". They have started writing programs in Codeworld together, and found it a very easy, fun experience. This talk will show off some programs and how they work. CodeWorld is great for beginners who want to learn Haskell with a richer environment than the REPL, and this talk will be suited both to those beginners, and also for experienced Haskell users looking for better, more interactive ways, to teach others.

Try it out at, and get more information at

8:00-9:00: Adam Chlipala - Ur/Web: A Simple Model for Programming the Web

Web applications are built on top of a ramshackle technology platform designed without consideration for classic software-engineering ideas like modularity.  Ur/Web is a programming language that hides the cruft behind the sorts of nice abstractions that functional programmers like.  The language design is inspired by not just Haskell and ML but also dependently typed languages like Coq and Agda.  The open-source implementation is decently practical, powering several production web sites (including at least one profitable business) and scoring well in third-party performance benchmarks (knocking the socks off of Haskell there, incidentally ;]).

I will start off with a few slides introducing the basic Ur/Web programming model, but I want to spend most of the time on a live-coding demo.  We will build up several versions of a simple chat application starting (almost) from scratch.  I encourage the audience to suggest coding variations, intentional errors that we hope the compiler catches, etc.!

Project web site:


Pizzas, salad and soda


If you can, please plan on arriving between 6:45pm and 7pm, but there will be someone in the lobby to greet stragglers.


If you'd like to stick around, a number of us tend to head down to the CBC or another pub afterwards to socialize. If you would like to give a talk or if you have any questions or concerns, please feel free to follow up here or email one of the organizers.

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  • Steven S.

    Argh, really hoped to make it (virtually) this month but I've got a clash with an immovable all-hands-on-deck meeting with my CEO!

    August 20, 2014

    • Josh C.

      We should definitely have video soon. I think everything went great too, so it'll be worth watching. But...I'm pretty biased since I talked :)

      August 21, 2014

  • Josh C.

    Thanks everyone for coming! I've posted my slides here: Hopefully we will have video soon, too.

    August 21, 2014

  • Bryce A.

    Thanks Josh, Jacy, and Adam for another great meetup. seems like an interesting project for teaching youth math and programming. I love Josh's presentations because they are given in a way that encourages friendly and fun crowd participation. Jacy's view on programming in Haskell and Minecraft was very interesting, as I find the Minecraft digit display far more complex than the Haskell, yet he would seem to disagree.
    Adams talk on Ur/Web was good and Ur/Web seems like a powerful tool for the tasks it was designed. It seems relatively simple to use and appears to offer a safer environment for someone to build an interactive web service than many of the popular stacks used today.

    1 · August 21, 2014

    • Josh C.

      Thanks Bryce! That's a really nice comment. I think that the Minecraft stuff would have went better if we had more time to explain it. I don't disagree though, it's definitely more complex than the Haskell version. But, I think that was part of the point - despite Minecraft being more complex, it's still more fun, and hopefully we can learn from that.

      August 21, 2014

  • Josh C.

    If there's anyone on the fence about coming, please read: A lot of work on CodeWorld has gotten done over the past two weeks (such advancement!), and I plan to show that it's not just for teaching kids about programming, but can be an absolutely great tool for anyone getting started with Haskell, and something that serious Haskell veterans will be extremely pleased to see. Additionally for advanced folks - it's just a really cool example of an awesome Haskell project.

    Come have fun!

    August 17, 2014

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