My whole point was that something like [a-] looks like it is a typo on the programmer's part. If I saw this in a script my first question would be "Did you mean something like [a-z]?" If I saw [-a] it doesn't look like a typo. Nor does [a\-] look like a typo. I can't really explain it any more clearly than this.

And I should note that this is a lot more trouble than I thought it would be. ;) Such a simple question shouldn't ever have to go to a Re^7...