Title: You Write, the Editor Replies

Dear Francis,

The Harpist's article "Being Idiomatic" in C Vu 11.5 was most interesting, but may I pick up on a minor thing? The Harpist's suggestion that long variable names break mathematical convention can easily be taken too far in cases where there are more than a very few variables. I have sat through lectures that have suffered from "running out of alphabet syndrome" and it is not fun, because all single-letter variables have to be held in short-term memory. By the time you have more than four or five variables, using longer names might improve things.

Using words also adds redundancy - you can guess your way through words more easily than you can guess your way through letters. I know not everybody is partially sighted, but many people have not-so-good handwriting. And if you ask any mathematician to choose a pair of variables, the chances are they're going to pick two that are not only adjacent alphabetically but also look similar, such as i/j, u/v or m/n (the latter also sound similar). My supervisors tell me that they under-stand my problem but they can't help it! And the variable 'a' can cause problems when referred to in prose, since the lower-case 'a' is a word in English.

An interesting aside is the problems that some Greek people have with lectures and books that mix Greek and Roman letters. One told me that these letters are easy to treat as equivalent if you are Greek, especially since contemporary Greece uses a character set that is much more Roman-like than the mathematicians make it out to be. I think the moral here is that what is idiomatic just might vary across cultures.

Of course, a name's length alone does not guarantee meaning. When I suggested to the GNU Music project that they try to use longer names, they replied by pointing out that one of their header files was called "windhoos_suck_suck_thank_you_cygnus.h" Hmmm....

Silas Brown <ssb22@cam.ac.uk>