Keynote The Value of Values - Rich Hickey

"Design Patterns" in Haskell tend to be rather meta. I think this is because most Haskell code I run into in the wild is able to do its job with a minimal amount of fuss and ceremony. You need some code to compute some thing? Oh, okay, so write out the formula/rules/process for computing your thing, and that's your Haskell program. And that's kinda all there is to it, usually. It tends to be excruciatingly straightforward. You probably want to take a look at An Introduction to Elm and elm-flatris and then elm-spa-example to get an idea about what I'm talking about. If there is one overriding theme in FP that could be called a "design pattern," it's this: make invalid states unrepresentable…

You're exactly right. That's why I chose 3.14 It looks like *Pi* but isn't *Pi*. 3.14 could be your volume, your interest rate, or how much in your checking account. Those may all change but 3.14 doesn't change. It may be the value of something, but that thing doesn't change *Pi*. S isn't the state, it's the **Type of the State being represented**. I personally would've picked the standard "T" for type, but doesn't matter much either way. If I may suggest, even though it's in another programming language (Clojure), Rich Hickey's talk "The Value of Values" is especially illuminating. One of my fav programming talks: link to this video