Rúnar Óli Bjarnason

Rúnar Óli Bjarnason (@runarorama)
Unison Computing

Rúnar is one of the authors of Functional Programming in Scala, and a cofounder of Unison Computing.


We all want to build systems that we can comprehend, and then use as components in further systems. Functional programming has an easy answer: functions are compositional. In this talk, we'll look at the abstract interface of composition, and maybe get some insight into what it all means.


This is a talk aimed at beginners and intermediate developers, about compositionality in software. We'll talk about what it is and why it matters, and what kinds of things prevent composition. We'll delve into category theory and talk about what "compositional reasoning" really means.