In bash (the default shell on Mac), today we wanted to execute a command over each line of some output, separately. We wanted to grep (aka search) for some text in a file, then count the characters in each matching line. For future reference… Perform a command repeatedly, once per line of input: grep “the” … Read moreRepeating commands in bash: per line, per word, and xargs
Today, I wanted to write a post about code that sorts a vector of maps. But I can’t write that without a test, now can I? And not just any test — a property-based test! I want to be sure my function works all the time, for all valid input. Also, I don’t want to … Read moreA monadically built generator
or, “Everything You Never Wanted to Know About java.util.concurrent.ExecutorService But Needed To” from StrangeLoop, 18 Sep 2014 Abstract: A careful design lets you write a concurrent application without thinking about deadlock or synchronization. Getting to that design takes a lot of thinking. This session delivers the background you need to make good decisions about concurrency … Read moreTalk: Concurrency Options on the JVM
Say I’m in retail, and the marketing team has an app that helps them evaluate the sales of various items. I’m working on a web service that, given an item, tells them how many purchases were influenced by various advertising channels: the mobile app, web ads, and spam email. The service will look up item … Read moreTDD with generative testing: an example in Ruby
Imagine that you’re writing a web service. It is implemented with a bunch of classes. Pretend this circle represents your service, and the shapes inside it are classes. The way I learned test-driven development[1], we wrote itty-bitty tests around every itty-bitty method in each class. Then maybe a few acceptance tests around the outside. This … Read moreTDD is Dead! Long Live TDD!
Meet my friend Sean. Sean is one of the most powerful developers I know. Not best, not brilliantest, but most powerful because: he provides more business value than some 50-person teams. What is the job title of such a powerful developer? It isn’t “ninja” (although maybe it should be). It’s “Accounting Manager.” WAT. Program: runs … Read moreThe power of embedded developers
Franklin Webber[1] went on a quest to find out whetherutility code was better or worse than core code in open sourceprojects. Utility code is defined as anything necessary but not directly related to the application’smission. Franklin found that overall quality of utility code was higher, perhaps because this code changes less. He also found a lot … Read moreMay I please have inlining for small dependencies?
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] … Read moreQuick reference: monads and test.check generators
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
Why replace our carefully chosen, exactingly specified example-based tests with properties, when properties are harder to write and less specific? link to YouTube Video from Midwest.io 2014 Related code: https://github.com/jessitron/scalacheck-prisoners-dilemma