David Abrahams wrote:
I learned this rule from Andrew Koenig, who said it was one of the surprising things he learned from his editors after writing his first book.
I believe the root for this rule being surprising is that just saying "this" in informal, spoken language is often not big of a problem, because the receiver of a message can ask if things are unclear. However, a book or technical documentation communicates in a unidirectional way and asking for clarification is usually not that easy (as we usually don't drink tea with the authors of our favourite books or papers on a regular basis -- and even if, we'ld most likely know more interesting things to talk about and/or forget to ask ;-) ). I learned from Dave's numerous comments on this topic, that for these reasons it's imporant to be careful with 'this', 'that' and 'it' in written language. Strict-typedness (in some ways) buys us the same sort of clarity when programming (with the unfortunate difference, that compiling natural languages involves much more human work). And even without a formal requirement, adding an antecedent to every 'this' there is would still make a lot of sense (as those of you who know Perl will most likely "use strict" if the program gets longer than a handful of lines). Just my EUR -,02. Regards, Tobias