In this post we will discover that the imperative programming style leads to monoidal IO, while using recursive style, which is more natural for functional programming, leads to monadic IO.

• code (literate haskell)

In this post we will discover and describe categories which admits monadic effects, we will build a free object of this type and show how to use it to build a typed safe state machine that was presented by Edwin Brady.

• code (literate haskell)

In this short post we explore the interplay of free monads and Kleisli categories.

• code (literate haskell)

In this post I model finite state machines using free categories; you will also get a gentle introduction to Kleisli categories, folds on free categories and finally tagless style. Based on a simple example of an FSM by Oscar Wickström.

• code (literate haskell)

Introduction to the monadicity theory based on free-algebras Haskell package.

• code

Link to free-algebra package on hackage.

The post was re-published on iohk blog.

Introduction to Universal Algebra, a mathematical discipline that is hidden under many constructions in Haskell ecosystem. It is more concrete than Category Theory, and hence often easier to understand. It is also a very useful source of examples in Category Theory.

My talk at Monadic Warsaw Haskell meetup on PureScript type system and composition of cofree comonads.

• youtube
• slides
• gist

Workshop on Category Theory

Workshop I gave at Monadic Party. Unfortunatelly, first 30 minutes of the recording was lost...

• youtube: lectures 1 & 2
• youtube: lectures 3 & 4

My talk at PureScript Conf 2017 (a satelite event of Lambda Conf 2017) about routing frontend applications using coffree comonad and modelling DOM with Coffree [].

• youtube
• slides
• code

Fun with Peano axioms in Haskell.