Haskell is—perhaps infamously—a lazy language. The basic idea of laziness is pretty easy to sum up in one sentence: values are only

This blog post was inspired by a recent Stack Overflow question. It also uses the Stack script interpreter for inline snippets if

First, the boring, not over-the-top version: the Stack team is starting a new initiative, the Stack Issue Triagers. We’re asking for volunteers

Let’s say we’re going to be writing some code that needs to know the current time. It would be inefficient to have

I’d really intended to write a blog post on a different topic this week. But given that I did some significant refactoring

For the past few years, Francesco Mazzoli and I have discussed issues around monad transformers—and the need to run their actions in

NOTE This blog post made the rounds last week before the branch was actually merged and the post was still on a

Streaming data is a problem domain I’ve played with a lot in Haskell. In Haskell, the closest we come to built-in streaming

This is a debugging story told completely out of order. In order to understand the ultimate bug, why it seemed to occur

This blog post came out of two unrelated sets of questions I received last week about usage of the resourcet library. For

Often times I’ll receive or read questions online about “design patterns” in Haskell. A common response is that Haskell doesn’t have them.

In the last post, we covered the following: What purity is and what it isn’t. We looked at functions and function composition.

This is a technical post series about pure functional programming. The intended audience is general programmers who are familiar with closures and

It’s always been clear to developers that a project’s source code and how to build that source code are inextricably linked. After

This blog post is about a pattern (pun not intended) I’ve used in my code for a while, and haven’t seen discussed