Computer Scientists: Is this a Donald Knuth joke?

Yes, the *Devil’s DP Dictionary *has entries for “Loop, endless… see endless loop.” and of course, “Endless loop … see loop, endless”.
the other explanation obviously (but less funny) is that it was generated by an automatic indexing system during typesetting.

I can’t imagine Knuth resorting to any automatic indexing system.

ETA I mean, obviously the printed index is automatically generated by (Knuth’s) typesetting system, but the terms to index he put into the book’s source file by hand.

Not directly related to this, but still an index inside joke.

George B. Thomas, author of the best-selling Introduction to Calculus and Analytic Geometry (a version of which was used by my high school, as well as at MIT, where Thomas taught) told our class this one himself.

If you go to the index in certain editions you find an entry for “whales”. If you then go to the page you won’t find a reference to whales. What you will find is a graph with one of those Richard Powers-esque mathematical blobs on the plot. Thomas and his editor, who were apparently going through the galleys by hand were getting pretty punchy by this point. One of them said that the shapes looked like whales, and the other suggested they put it in the index. So there’s a reference to “whales” in the index of a calculus book because a tired and sleep-deprived author and editor thought it was funny that a pair of mathematical curves looked like a whale.

Shouldn’t the MMIX version have already come out a decade ago?

MMIX itself did (or has it been two decades?), but revising Volumes 1-3 had to wait until Knuth finished volumes 4 and 5. Meanwhile all the programs are available in MMIX on the pages of the MMIX Users’ Group.

Re. index fun: I saw some technical book (in English) deliberately index an egregiously humungous German compound word, which is quite noticeable when you flip the pages.

No, two decades ago was the MIM version.

Knuth also published in Mad Magazine.

It doesn’t do much to explain the joke in the OP, but just yesterday I was just reading about another self-referential book index entry. Mathematician Paul Halmos promised his colleague G.P. Hochschild that he would put him in his book Finite Dimensional Vector Spaces. The index entry on page 198, naturally, reads “Hochschild, G. P., 198.” More information here.

Not entirely accurate. You can put the index entries into your tex file and it will be written to a special .idx file, but it requires a third party program called makeindex to actually turn it into an index file that tex can read.

Speaking of user groups, the tex user group TUG is alive and well and is enormously successful in promoting tex around the world.

The guy was a laugh a minute.

Godel, Escher, Bach had recursive index entries I’m pretty sure because, duh, Hofstadter.

I meant that the words to index are marked in the tex file by the author, instead of a computer program automatically generating a list of keywords or a concordance. You can tell Knuth does it this way because of his little jokes and the overall high quality of the index.

For the actual compilation, xindy may be more flexible than makeindex.

Speaking of Knuth’s typesetting, in the TeXbook there is a chapter explaining how to work with macros. The page headers say “Definitions (also called Macros)”, except on one page where it reads, “Definitions (aka Macros)”. Could somebody explain the joke?

Another example of Knuth’s whimsy is his article on the complexity of songs.

In 1981 I was working at a company using PR1ME computers. One of the manuals had these index entries:
recursion: See circular reference

circular reference: See recursion
Recursion and circular references are not exactly the same thing but I did get a chuckle out of it.

As someone who regularly watches Johnny Carson on AntennaTV, I agree heartily.

Yes, and I came here to say that.

I also said that, here.

:smiley: