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main = getArgs >>= readFile . head >>= print . length Even though length is a pure function, this is where the I/O will happen (lazily), which means that is where any exceptions relating to I/O will get raised. Pure code should avoid raising exceptions, which this example violates. Problem 2: Sharing may cause file contents to remain in memory Because of the way that lazy I/O reads in strings, thi

In an effort to better understand parsing in the Haskell world, I decided to port a hand-crafted parser I’d written for Subversion dump files in C++11 into a Haskell version. It’s not that the old parser didn’t work well, but I wanted to see what Haskell could make of the problem with its laziness and combinator-oriented parsing libraries. If you want to follow along in your editor, here is the C+

This is not a tutoral on monads, nor will I use any math terms here. This is for people who have learned enough about monads to use them, but want to get a better picture of what they’re doing and why they exist. Functions One way to develop a first intuition about monads is to follow the progression of abstractions from functions to monads. Here is a simple picture of what a function does. I’ve p

In my pursuit to understand Git, it’s been helpful for me to understand it from the bottom up – rather than look at it only in terms of its high-level commands. And since Git is so beautifully simple when viewed this way, I thought others might be interested to read what I’ve found, and perhaps avoid the pain I went through finding it. The following article offers what I’ve learned on this journey

As some one who has enjoyed the Lisp language (in several flavors) for about 15 years now, I wanted to express some of my reactions at recently discovering Haskell, and why it has supplanted Lisp as the apple of my eye. Perhaps it will encourage others to explore this strange, wonderful world, where it looks like some pretty damn cool ideas are starting to peek over the horizon. First, let me say

The following document describes how to use Carsten Dominik’s excellent org-mode Emacs package after the fashion of a pen-and-paper day planner. For those curious, I was not brought up on time management in the era of the current GTD fad. I started with a hard-bound book filled with daily planning sheets, along with training and books supporting this method. I found it incredibly useful for the th