Digital Digressions by Stuart Sierra
From programming to everything else
Perl was the first programming language I really liked, the first language that made programming fun. Perl has three basic types: “scalars” for atomic values, arrays for ordered sets, and hash tables for unordered sets. (Yes, there are others, but those are the popular ones.) I quickly discovered that these three types can be combined…
Ah, the loop, so fundamental to programming it’s hard to imagine a single program without one. After all, what’s the use of calculating just one thing? Usually you have a big pile of things you want to calculate, which is why you need a computer in the first place. I think one of the quickest…
As part of my exploration of Ruby, I attended Francis Hwang’s presentation to the New York Linux Users’ Group. One feature that caught my interest in his talk was the OpenStruct class, which lets you assign values to arbitrary “slots” within an object. require ‘ostruct’ me = OpenStruct.new me.name = "Stuart Sierra" me.net_worth = -500…
An excellent article introducing the concepts and advantages of functional programming in non-academic language. Now if I could just understand monads…
A popular game on comp.lang.lisp is comparing Lisp with Python. Lispers complain that Python has a crippled lambda and no lexical closures, and they hiss and boo whenever Python’s development tends in a non-functional direction. I’ve recently been playing with Ruby. Lo and behold, it has real lambdas, closures, and a generally more functional style.…
One big difference between Lisp and most other programming languages is its use of recursion instead of iteration. So while I was working on some text-parsing code, I fell in to this simple pattern: (defun process (list) (if list (cons (do-something (first list)) (process (rest list))))) Ah, the joys of Lisp-2. If do-something were actually…
Or, What I Have In Common With Craig Silverstein. I’ve been enjoying John Battele’s The Search, a history of the search engine business from Archie to Google. He quotes Google’s first employee, Craig Silverstein, as saying, “I would like to see the search engines become like the computers in Star Trek. You talk to them…
So it turns out that nearly every binary search algorithm is broken. Why? Fixed-sized integers, a holdover from machine programming that still lingers in supposedly modern languages like Java. LtU’ers are haggling to decide if it’s a type error, a bad data structure, a language defect, a failure of correctness proofs, or just a bug.…
Despite all of the AJAX/Web 2.0 hype, the fact remains that most web pages are mostly static. The most efficient way to serve static pages is unquestionably to store them as static files on a file-based web server such as Apache. I add new pages to this site once every few days at most, but…
Fiddling with some Common Lisp code a few weeks ago, I needed to push items onto the end of a list. After thinking for a moment, I wrote this: (defun push-end (object place) (nconc place (list object)) Since I was fiddling in LispWorks at the time, I discovered that LispWorks already defines its own push-end…