Re: iff vs. if in documents

["Jeanne A. E. DeVoto" <jaed -at- jaedworks -dot- com>]

At 11:27 AM -0800 1/19/2000, Jesse N. Alexander wrote:
>A potential client was complaining about a writer who marked all the "iff"s
>in software comments (where iff would normally be appropriate) as spelling
>errors. But the couple paragraphs of the draft software description (that
>were extracted from the comments in the code) seemed fine to me with the
>"if"s. (Granted that the client didn't explain what the code was supposed to
>do.) And since then, I have not been able to come up with a single "English"
>example in which "if" is not just as good as, or better than "iff".

OK. First off, my feeling is that a writer who marks up words used in code
- even within comments - as "spelling errors" is, well, problematic to
begin with. Shorthand, acronyms, and jargon are often used in source
comments. They're not sacrosanct in the same way the actual code must be,
but they should never be changed without consulting the person who wrote
the code.

Second, "if and only if" does not mean the same thing as "if". Substituting
one for the other is never appropriate, at least not if "if and only if"
was used correctly in the first place. It might be reasonable to recommend
expanding "iff" to "if and only if" in the comments, depending on whether
the audience is sophisticated enough to recognize the shorter form, but
replacing it with a term that means something else would be folly.
Especially in source code, a mode in which conveying exact logical meaning
is of critical importance.

It's possible, of course, that the programmer who wrote the code and
comments used "iff" where "if" was meant. But before you even think about
making this change, you need to be extremely certain that you understand
the program logic well enough to correct the comments.

--
jeanne a. e. devoto ~ jaed -at- jaedworks -dot- com
http://www.jaedworks.com