Category Archives: Type Class

Lens, State is your father… and I can prove it!

Posted on January 24, 2018 by

Here it is our new blog post, as a sequel of Lens, State Is Your Father. Today, we’ll try to formalize some informal claims that we did in that article and we’ll emphasize on the relevance of proof assistants in … Continue reading →

Posted in coq, Lens, monad, Optics, proof, Scala, State, Type Class | Leave a comment

Functional APIs: an OOP approach to FP

Posted on June 26, 2017 by

In the series of posts about the essence of functional programming, we’ve already seen how we can build purely declarative programs using GADTs. This is a picture of what we got (using more standard cats/scalaz data types): This program above … Continue reading →

Posted in algebra, functional programming, Scala, Type Class | Leave a comment

Lens, State Is Your Father

Posted on November 10, 2016 by

In our last post, we introduced IOCoalgebras as an alternative way of representing coalgebras from an algebraic viewpoint, where Lens was used as a guiding example. In fact, lens is an abstraction that belongs to the group of Optics, a … Continue reading →

Posted in algebra, coalgebra, Lens, Optics, State, Type Class | Leave a comment

Yo Dawg, We Put an Algebra in Your Coalgebra

Posted on October 11, 2016 by

As Dan Piponi suggested in Cofree Meets Free, we may think of coalgebraic things as machines with buttons. In this post, we take this metaphor seriously and show how we can use algebras to model the Input/Output interface of the … Continue reading →

Posted in algebra, coalgebra, Embedded DSLs, machine, Scala, Type Class | 2 Comments

Updating immutable objects in generic contexts

Posted on March 7, 2013 by

Immutability is one of the hallmarks of functional design, and writing idiomatic programs in Scala highly relies on manipulating immutable objects. Now, if we don’t have mutable fields (aka vars) … how can we update objects in a convenient way? … Continue reading →

Posted in case classes, immutability, Macros, Scala, Speech, Type Class, Updatable | 1 Comment