Donald Knuth Rips On Unit Tests and More

eldavojohn writes "You may be familiar with Donald Knuth from his famous Art of Computer Programming books but he's also the father of TeX and, arguably, one of the founders of open source. There's an interesting interview where he says a lot of stuff I wouldn't have predicted. One of the first surprises to me was that he didn't seem to be a huge proponent of unit tests. I use JUnit to test parts of my projects maybe 200 times a day but Knuth calls that kind of practice a 'waste of time' and claims 'nothing needs to be "mocked up."' He also states that methods to write software to take advantage of parallel programming hardware (like multi-core systems that we've discussed) are too difficult for him to tackle due to ever-changing hardware. He even goes so far as to vent about his unhappiness toward chipmakers for forcing us into the multicore realm. He pitches his idea of 'literate programming' which I must admit I've never heard of but find it intriguing. At the end, he even remarks on his adage that young people shouldn't do things just because they're trendy. Whether you love him or hate him, he sure has some interesting/flame-bait things to say."

Comments

Shocked

[gowen]

He pitches his idea of "literate programming" which I must admit I've never heard of

I'm shocked to discover that Knuth is taking an opportunity to push literate programming, given that he's been pushing literate programming at every opportunity for at least 25 years.

Now, I've no problem with literate programming, but given that even semi-literate practices like "write good comments" hasn't caught on in many places, I think Don is flogging a dead horse by suggesting that code should be entirely documentation driven.

What?

[TheRaven64]

You've heard of TeX, written in Web, the language designed for Literate Programming, but you've not heard of Literate Programming?

I have a lot of respect for Knuth as an algorithms guy, but anything he says about programming needs to be taken with a grain of salt. When he created the TeX language, he lost all credibility - designing a language in 1978 which makes structured programming almost impossible is just insane. TeX gets a lot of praise as being 'bug free,' but that's really only half true. The core of TeX is a virtual machine and a set of typesetting algorithms, both of which are very simple pieces of code (they'd have to be to run on a PDP-10). Most of the bits people actually use are then metaprogrammed on top of the virtual machine, and frequently contain bugs which are a colossal pain to track down because of the inherent flaws in the language (no scoping, for example).

If you want to learn about algorithms, listen to Donald Knuth and you will learn a great deal. If you want to learn about programming, listen to Edsger Dijkstra or Alan Kay.

Re:What?

[cbart387]

If you want to learn about algorithms, listen to Donald Knuth and you will learn a great deal. If you want to learn about programming, listen to Edsger Dijkstra or Alan Kay. For those that didn't read the article, Knuth expressed criticism on several of the questions asked, but he didn't want to just duck the question. For instance, the 'trendy question' he said this.

With the caveat that thereâ(TM)s no reason anybody should care about the opinions of a computer scientist/mathematician like me regarding software development

Re:Unit Tests are not wasteful

[seaturnip]

It actually doesn't sound to me like Knuth has heard of the term 'unit test' before this interview at all. It sounds like he thinks it means prototyping a function before writing the real version. Given that he likes to push his model of documentation-driven programming, I think he might be more sympathetic to unit tests if he understood that they can serve as a kind of formalized documentation.