Monday, October 5, 2015

Software Craftsmanship Barcelona 2015

Last weekend I attended the Software Craftsmanship Barcelona 2015. This was the first time I participate as an attendee (I had worked in the organization of the first two editions).

It was a great event. I attended very interesting talks and had amazing conversations with many people. Some of them I already knew from the Barcelona, Zaragoza, Bilbao, Canarias and Valencia community or from abroad but many of them I just met there.

If I had to highlight my favorite talk, I'd choose Accesibilidad en el software. ¿Qué es? ¿Por qué es importante? (Software Accessibility. What is it? Why is it important?) by Juanjo

Juanjo is a great developer and an accessibility specialist. He also happens to be blind.

He showed us how he programs with Visual Studio using a screen reader and knowing nearly every keyword shortcut. It was very impressive.

Personally, I found it amazing how the human brain adapts to different situations. He has developed a great memory and is able to mentally "visualize" the code with just hearing it once (at a really fast speed).

He also told us about several applications he'd made in his spare time to improve his and another blind people's daily life.

I also enjoyed very much Vicenç García-Altés' talk about Mutation Testing, Álvaro García's talk Tu carrera como una marathon (Your career as a marathon) and the Yatzy refactoring kata also facilitated by Álvaro.
We (the No Flop Squad) also participated in the SCBCN15.

The afternoon before the SCBCN15 we facilitated a Pre-SCBCN15 coding dojo.

We practiced doing the Business Rules kata but with the constraint of having to develop an internal DSL that make the tests read nearly as the business rules it was testing. The constraint was based on an exercise Xavi Gost and I did to practice together in one of my last visits to Valencia. This constraint forces you to stay more time on the problem space before passing to the solution space.
We received a lot of positive feedback.

On Saturday morning we gave a talk in which we spoke about an ongoing experiment that we've been developing during the last month: Hybrid Persistence.

In this experiment, we are exploring the idea of persisting different parts of the state of an aggregate on different data storage technologies depending on the kind of state. The idea is similar to Polyglot Persistence but it works at a finer grain persisting separately the identity and mutable state of each member of the aggregate. The relationships among members of the aggregate can also be persisted independently.

The experiment is still in an initial phase, so we haven't yet reached to any sound conclusions. In the talk, we explained the ideas behind this exploration, what we have seen so far (including dead-ends, mistakes and successes) and the things we'd like to try next.

On Sunday afternoon there was an Open Space .

A session that I really enjoyed and took a lot of ideas from, was Dinamizando las comunidades locales (Energizing local communities)

in which organizers and members of several communities across Spain, shared our experiments, successes and failures in trying to improve and sustain our communities.

Also while we were selecting the open space grid, someone nominated a session asking me to give a short introduction to Clojure. Surprisingly it received enough votes to be selected so I had to improvise it.

I showed some code examples and used LightTable to write and evaluate expressions on the fly while I was explaining some language features. Álvaro helped me (thanks!) writing on Juanjo's laptop the code I was writing on my laptop and showing on the screen so that he could also follow the talk using his screen reader.

I tried to demystify parentheses and prefix notation, and explain some of the simplest goodies of the language. Even though it wasn't a good talk, I think I managed to at least arise the curiosity of some of the attendees. I also invited all to come to the Clojure Developers Barcelona's Introduction to Clojure event on next October 27th.

There were so many other interesting talks I couldn't see. I can't wait for the videos to be published.

All in all, it was a wonderful event.

I'd like to thank from here all the attendees and the organization for making it possible. I'd also like to thank Netmind for letting us use their facilities for free one more time.

Saturday, October 3, 2015

Kata: Cellular Automata in Clojure

I just did the Cellular Automata kata in Clojure.

These are the tests using Midje:

and this is the resulting code:

where I added a function print-evolution to visualize the evolution on the REPL

As usual I used a mix of TDD and REPL-driven development committing after each green and each refactoring. I also committed the REPL history.

See all the commits here if you want to follow the process.

You can find all the code on GitHub.

Friday, October 2, 2015

Interesting Talk: "One Ring to Bind Them"

I've just watched this wonderful talk by Mark McGranaghan: It contains very interesting ideas on library design.

These are the slides.

Revisiting Writing Readable Clojure code

After reading this wonderful post by Adam Bard, Writing Friendlier Clojure, I've revisited the second Clojure talk I attended to.

It was Writing Readable Clojure code by Jiří Knesl.

It impressed me and influenced my Clojure code a lot.