Recently I attended the ACCU conference in Bristol and got to experience what it feels like to deliver something that went down like a lead balloon. One evening many moons ago, I thought I'd send in a proposal. By some small miracle I got accepted and was all set to run a 90 minute introduction to Haskell.
I'd already run through the workshop once at a local user group. The material isn't amazing, but I was confident in delivering it and thought it offered people a chance to get a taste of Haskell and programming with functions.
Then the problems started. It's ACCU. It's full of clever people, therefore I should level-up the material and assume more knowledge. Right? I should make it more hands-on, more interactive and better in every way.
I prepared hard. I updated the slides. I added more and more. I wrote notes, I dug references and I was confident it would kick-ass.
And then the day arrived.
90 minutes seem like a long time. It isn't. I spent a good 15 minutes ensuring that everyone could run "hello world". Very rapidly 90 minutes because 60 minutes.
Then my cleverness got the better of me. The Curry-Howard isomorphism is fascinating, but perhaps it's not the best subject matter within the first 30 minutes of any presentation. Trying to explain it under pressure with questions from an audience eager to learn makes it even worse. I probably lost another 20 minutes trying and failing to explain that
const :: a -> b -> aonly has one valid implementation in Haskell. And what the hell are the poor attendees going to do with this information? GAH!
And so it continued. On to writing some code. I'd wanted to make it easier to compose higher order functions to produce results, so I'd made the initial data structures in the exercises a bit more complicated than those I'd shown in the example slides. Big mistake. This made it much harder for people to grok the syntax; I'd shown simple syntax but not given enough direction. 30 minutes rapidly disappeared and I'm now *way* behind schedule.
At this point, I'd already realized the situation was going Pete Tong. But what'd you do? You can't just down tools and walk out the room (well, I suppose you could, but that'd be worse), so you just have to knuckle down and carry on. And carry on I did, through more examples (well over-egged) and then onto the Universality of Fold (brain, what the hell are you thinking?!).
With 5 minutes left, there's plenty of time to through a demo of QuickCheck in, right?But then, I realized I'm in an Emacs buffer. How'd I increase the font-size so people can read it? GNARGH!! It's over to Notepad and bump the fonts up in that. "Should have used vi!" went the audience. ARGH!
And then the buzzer sounds (well, not really, but it's time to go). Bring things to a halt and escape to a corner of the building. I can't imagine that was particularly fun for the participants. A few people kept up (hurrah!) and there were a couple of positive things said, but I knew it'd gone wrong and it boy that doesn't feel good.
So, at least now I know how it feels (bad, very bad) and I also learnt an important lesson. Keep the message simple! Focus on the single takeaway you want participants to have. I wanted people to leave knowing that Haskell isn't impenetrable and looking at how far you can get just by reading type signatures. However, I lost this in a noise of other random related things and tried (and failed) to communicate a million and one other features.