Perl Debugged

8.1. Typo Pathologies

Later we'll tackle the more complex issues of errors committed when you typed exactly what you intended to type, but the program still fails to work. This chapter discusses the humble typo: if you could see it, you'd know it was a mistake, and how to fix it.

The trick is to find the typo in the first place. We will unfurl an array of techniques for zeroing in on the miscreant. Fortunately, the scope of the typo is not unlimited; seldom does someone type a word entirely different from the one they were thinking of, for instance. The following quote from the Cambridge doctoral thesis of Stephen Moss appositely states the possible choices, although he was referring to the effect of channel errors on textual transmission: