functionalPrinciples

Functional principles come together in GraphQL at React Rally

May 26, 2019August 25, 2015 by jessitron

Sometimes multiple pieces of the industry converge on an idea fromdifferent directions. This is a sign the idea is important. Yesterday I spoke at React Rally (video coming later) about theconfluence of React and Flux in the front end with functionalprogramming in the back end. Both embody principles of composition, declarativestyle, isolation, and unidirectional flow … Read moreFunctional principles come together in GraphQL at React Rally

Data-in, Data-out

May 26, 2019August 3, 2015 by jessitron

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 … Read moreData-in, Data-out

Data Flows One Way

May 26, 2019June 18, 2014 by jessitron

At QCon NY, Adam Ernst talked about the way Facebook is rewriting their UIs to use a functional approach. When all the UI components subscribing to the model, and the model subscribing to UI components (even through the controller), it’s a whole wad of interconnectedness. Instead, it has been decreed that all data flows from … Read moreData Flows One Way

Limitations of Abstraction, and the Code+Coder symbiosis

May 26, 2019June 18, 2014 by jessitron

Notes from #qconnewyorkI went into programming because I loved the predictability of it. Unlike physics, programs were deterministic at every scale. That’s not true anymore – and it doesn’t mean programming isn’t fun. This came out in some themes of QCon New York 2014. In the evening keynote, Peter Wang told us we’ve been sitting … Read moreLimitations of Abstraction, and the Code+Coder symbiosis

Left to right, top to bottom

May 26, 2019April 22, 2014 by jessitron

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 … Read moreLeft to right, top to bottom

Talk: Functional Principles for OO Developers (Ruby edition)

November 27, 2020November 27, 2013 by jessitron

Back in my early conference days, I found that I liked all the Ruby developers. So I learned Ruby in order to translate this talk into one I could give at a Ruby conference. It turned out well.

Idempotence in math and computing

May 26, 2019August 31, 2013 by jessitron

“Idempotent” is a big word. It’s one of the four-dollar words thrown around by functional programmers, and it confuses people — including functional programmers. This is because we don’t use it consistently. In math, idempotence describes only unary functions that you can call on their own output. Math-idempotence is, “If you take the absolute value … Read moreIdempotence in math and computing

Twisting the rules of logic in our code

May 31, 2013 by jessitron

In philosophy, there are very few things that can’t be doubted. The basic laws of logic are among them. There’s one that seems completely obvious and indisputable to normal people: Law of Identity: Everything is identical to itself. In my audiobook, the professor is going on about how not only is this statement true in … Read moreTwisting the rules of logic in our code

Static Methods Are Your Friend

March 6, 2012 by jessitron

There’s an age-old debate about whether static methods are the devil. They make unit testing so hard! Utility methods are easier to use when they’re static. Take for instance a simple method to pull the value of a cookie off an HttpServletRequest. Since this is Java, we can’t put the method on the HttpServletRequest class. … Read moreStatic Methods Are Your Friend