Past Meetup and Ur/Web

This Meetup is past

40 people went

Location image of event venue


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.