This talk about gradual typing in Clojure makes a case for combining dynamic languages with slowly-more-specific typing. (These days, I like TypeScript for this.) First delivery, Philly ETE ,April 2015: Also, PolyConf in Poznan, July 2015: PolyConf 15: Contracts as Types / Jessica Kerr – YouTube I wish I could find the version from Craft …
I never enjoyed front-end development, until I found Elm. JavaScript with its `undefined`, its untyped functions, its widely scoped mutable variables. It’s like Play-Doh, it’s so malleable. And when I try to make a sculpture, the arms fall off. It takes a lot of skill to make Play-Doh look good. Then Richard talked me into …
Read moreAn Opening Example of Elm: building HTML by parsing parameters
In functional programming, we try to keep our functions data-in, data-out: they take some data as parameters, return some data as output, and that’s it. Nothing else. No dialog boxes pop, no environment variables are read, no database rows are written, no files are accessed. No global state is read or written. The output of …
Darn side-effecting programs. Programs that change things in the outside world are so darn useful, and such a pain to test.For every piece of code, there is another piece of code that answers the question, “How do I know that code works?” Sometimes that’s more work than the code itself — but there is hope. …
My coworker Tom finds Ruby unreadable. What?? I’m thinking. Ruby can be quite expressive, even beautiful. But Tom can’t be sure what Ruby is going to do. Some imported code could be modifying methods on built-in classes. You can never be sure exactly what will happen when this Ruby code executes. He’s right about that. …
Combine monads with test.check generators to build them up out of smaller generators with dependencies: (require ‘[clojure.test.check.generators :as gen])(require ‘[clojure.algo.monads :as m])(m/defmonad gen-m [m-bind gen/bind m-result gen/return]) (def vector-and-elem (m/domonad gen-m [n (gen/choose 1 10) v (gen/vector gen/int n) e (gen/element v)] [v, e])) (gen/sample vector-and-elem);; ([[0 0] 0] [[0 -1 1 0 -1 0 -1 1] 0] …
In this live video interview with screencasting, I show a bit of functional programming style in Java 8. I also rant about whether math is necessary to be a good programmer, and predict how organizational structures are changing to support learning. STLCodeCast Episode 19 My Pluralsight course on FP with Java
The other day at work, we had this problem: Sort a sequence of rows, based on an input list of columns, where each column might be sorted ascending or descending, and each column might require a transformation first to get to something comparable. The function interface looks like this: Here is a concrete example where …
TL;DR – Clojure’s threading macro keeps code in a legible order, and it’s more extensible than methods. When we create methods in classes, we like that we’re grouping operations with related data. It’s a useful organizational scheme. There’s another reason to like methods: they put the code in an order that’s easy to read. In …
In the left corner, we have Functional Programming. FP says, “Classes shall be immutable!” In the right corner, we have Object-Oriented programming. It says, “Classes shall be extendable!” The battlefield: define a method on the abstract class such that, when you call it, you get the same concrete class back. In Scala.Fight! Here comes the …