Continuation passing style Free Monads and direct style Free Monads
Generalized Algebraic Data Types gives us the power to develop type-safe Free Monads, without having to rely on continuation passing style.
Posts by categories
- functional-programming 29
- modern-cpp 7
- software-design 5
- random-rambling 3
- machine-learning 3
- system-design 2
functional-programming
Answering r/haskell: How to unit test code that uses polymorphic interfaces?
My answer to the question asked on r/haskell on how to test code that lives in a Monad class with polymorphic functions.
Free Monads: from the basics to composable and effectful stream processing
Let’s embark in a journey, from Free Monad basics to more advanced examples such as stream processing as done in IdrisPipes.
IdrisPipes: a library for composable and effectful stream processing in Idris
Our goal here is to provide Idris with a library for composable and effectful production, transformation and consumption of streams of data.
Transforming data structures into types: an introduction to dependent typing and its benefits
A showcase of how dependent typing can help both to increase type-safety and reduce to zero the cost of change when introducing type-safety in legacy code.
List Monad connection with Non-deterministic Polynomial time complexity
A problem is in NP if it can be solved by an algorithm that runs in polynomial time on a non-deterministic Turing Machine, a computer that can “guess” which ...
Implementing Clojure-like Transducers in Idris: advanced transducers
Part 2 of our implementation of transducers in Idris. This time we tackle stateful transducers and transducers with completion steps.
Implementing Clojure-like Transducers in Idris: definitions & concepts
Let’s implement a small transducer-like library in Idris, for efficient and composable algorithmic transformations.
Idris dependent typing challenge: Bowling Kata
Let’s implement an entirely type safe bowling game, where invalid games cannot even be instantiated, and see how it goes and if it is even desirable.
10 things Idris improved over Haskell
The 1.0.0 of Idris has been released just a few months back, just enough to start trying out the language and some of the possibilities dependent typing offers
Paramorph your DSL (C++)
Let’s dive in the implementation of paramorphisms in C++, a strictly more powerful recursion scheme than catamorphism, all motivated by an example.
Building a Clojurescript Game Logic
Let us implement a board game in ClojureScript, a functional programming language transpiling to JS, from the game rules to graphics to AI (part 3).
Building a Clojurescript game (POC)
Let us implement a board game in ClojureScript, a functional programming language transpiling to JS, from the game rules to graphics to AI (part 2).
Building a Clojurescript game
Let us implement a board game in ClojureScript, a functional programming language transpiling to JS, from the game rules to graphics to AI (part 1).
Quickcheck is fun, deal with it
QuickCheck’s generators can be leveraged for other purposes than just Property Based Testing. Let’s embrace the absurd world of generating random stuff!
Experimenting with QuickCheck on a DSL
After having spent the last three posts exploring how to implement our own QuickCheck, the goal of the next two posts will be to play with it, to test and di...
Code your own Quick Check (Shrink)
In the previous posts, we started to implement our own QuickCheck in Haskell, which we named RapidCheck, based on the original publication on QuickCheck.
Code your own Quick Check (Higher Order Functions)
In the previous post, we started to build our own QuickCheck implementation in Haskell, which we named RapidCheck. We went over the basic concepts needed to ...
Code your own Quick Check
In the next posts, we will go through a small implementation challenge. The goal will be to implement our own limited version of QuickCheck, the famous gener...
Catamorph your DSL (C++ Port)
In the previous posts, we went over the process of building a DSL for arithmetic operations and we introduced the concept of Catamorphism as a way to decoupl...
Catamorph your DSL (Clojure)
In the previous three posts, we went over the process of building a DSL for arithmetic operations and we introduced the concept of Catamorphism as a way to d...
Catamorph your DSL (Trade-offs)
This post is a third of the series of post dedicated to notion of Catamorphisms and its application to build Domain Specific Languages (DSLs).
Catamorph your DSL (Deep Dive)
This post is a second of the series of post dedicated to notion of Catamorphisms and its application to build Domain Specific Languages (DSLs).
Catamorph your DSL (Introduction)
I recently had the pleasure to go to a Haskell workshop on Domain Specific Languages (DSL). The goal was to teach us the basics on how to build a DSL.
Folding merge sort (Haskell)
Implementing a merge sort in terms of a fold (left to right scan) is possible. Here is how in Haskell.
Meetup Report: The philosophy of FP
My meetup report on a talk by Arnaud Lemaire introducing the philosophy behind functional programming.
Open Recursion (Performance)
In the two previous posts, we used open recursion to provide efficient solutions to dynamic programming problems, keeping the following aspects decoupled:
Open Recursion (C++)
In the previous post, we explored how we could leverage open recursion to solve a dynamic programming problem, while keeping the following aspect decoupled:
Open Recursion (Haskell)
There is a large class of problems that we can solve by nice mathematical recurrence relations.
modern-cpp
CPPP19 Trip report - The first edition of the first french C++ conference
Last Saturday marked the first occurrence of the CPPP, the first conference dedicated to C++ on the French soil, organized by Frédéric Tingaud and Joel Falcou.
Pythagorean Triples in Modern C++
Generating Pythagorean triples using linear algrebra in modern C++ as an answer to the heated discussions around std::ranges in the C++ community.
Why template parameters of dependent type names cannot be deduced, and what to do about it
C++ template parameters of dependent type names cannot be deduced. Let’s see why C++ cannot do much better considering its type system and some basic maths.
Lost in std::is_permutation complexity (reddit answer)
Answering comments on the usefulness of property based testing to ensure correctness of unstable sort.
How to improve std::is_permutation complexity
Exploring alternatives to the hopelessly inefficient std::is_permutation.
Lost in std::is_permutation complexity
This post is dedicated to an STL algorithm which caused me some serious performance issues at my first use of it: std::is_permutation.
Accumulating merge sort (C++)
Implementing a merge sort in terms of a std::accumulate (left to right scan) is possible. Here is how to merge sort using only ForwardIterators.
software-design
Monoids: what they are, why they are useful, and what they teach us about software
Monoids are a pretty interesting concept in software development. Monoids are everywhere. Monoids are simple yet powerful. And Monoids have a lot to teach us...
Money class design: why not having currencies as type parameters?
A follow up on the study of the ideal design for the Money class, answering an interesting question on Reddit.
A study of 4 Money class designs, featuring Martin Fowler, Kent Beck and Ward Cunningham designs.
Let’s look at the Money class implementations found in Kent Beck, Martin Fowler and Ward Cunningham work, and propose a new one based on dependent typing.
Hexagonal Architecture and Free Monad: Two related design patterns?
In today’s post, we will explore the hexagonal architecture through an example, describe it, and relate it to Free Monads, a well-known and pretty popular pa...
Meetup Report: Better tests Kata night
How to design better tests? How to code using Test Driven Development? My takeways of a very instructive meetup with Romeu Moura.
random-rambling
Statistical gender bias
I recently stumbled on a debate where J. Peterson argues that the gender pay gap is mostly not due to gender bias. Let’s see what’s wrong with his argument.
How wind affects your speed on a bike
Let’s look at how the wind affect your speed on a bike, the diminishing impact of power, and why you feel the drag suddenly passed a certain speed.
By how much is my smart watch overestimating my distance?
Watching my GPS tracking data, I noticed my track is oscillating around my true trajectory. How much extra distance is it?
machine-learning
Understanding perplexity and its relation to cross-entropy and compression
Modern conditional and unconditional language models often report their perplexity as validation metrics. Let’s see what it means.
Auto-regressive language models don’t necessarily sample the most probable sentences
Have you even tried to sample greedily from a language model. It’s not a good idea. Let’s discuss why.
COVID cases from COVID test results
Let’s create a simple Bayesian network to visualise how reported positive tests of COVID inform us about the real number of COVID infections.
system-design
Distributed agreement on random order: Lamport Timestamps
If we succeed in this task, we will have succeeded in building what easily qualifies as one of the world most wasteful way to random shuffle. We now have a s...
Small programming faults can overflow an entire system
A short story on the impact of ignoring errors and not knowing error modes in distributed systems, and how it lead to paralyse an entire system.