On 4/24/07, Larry Wall <[EMAIL PROTECTED]> wrote:
On Tue, Apr 24, 2007 at 06:45:12PM -0400, Charles Bailey wrote: : On 4/17/07, [EMAIL PROTECTED] <[EMAIL PROTECTED]> wrote: : >Note that unless no longer allows an else : It's probably that I'm just having another day where skull > brain, but I'm : not sure I see the benefit to the language here. : : I think of "unless" as an alternate spelling for "if not", so it seems : natural that it be possible to follow it with an "else". I'll grant that : the (common) idiomatic usage of "unless" doesn't include an "else", but that : seems more an argument not to use an "else" rather than to forbid it. It's : a bit like saying one can "continue" after a "while" but not an "until". : : Is there a parsing advantage that I've missed, or does it disambiguate some : other construct? Yes, it's slightly easier to parse this way, and yes, it bugs me that unless/else is not English, but mostly I changed it as a not-so-gentle prod towards refactoring, based on the notion that if you have to install a guard on a storage location being false, you've probably got the scope of the storage location wrong. And even if not, there are several other ways to write it, at least one of which will be generally more readable to other people. I freely admit that it's less orthogonal and that I'm being high-handed. :)
For situations such as this we have Rule One. But I think I'd still ask you to reconsider, in a low-priority thread somewhere. My sense is that the driving consideration is more a use case than an intrinsic element of language structure (to the extent that the two are separable), and would have a more natural home in a pragma like Design::BestPractice (or Lingua::Franca or Wheels::Training or Lingua::Fascist, depending on one's point of view). Maybe I'm just thinking too neutrally of unless === if not, rather than unless === if shouldn't be. Either way, it's a pretty minor point -- certainly nothing as mind-bending as a good JAPH or with the scary security implications of parens-specify-an-executable-block, so 'nuff said. -- Regards, Charles Bailey Lists: bailey _dot_ charles _at_ gmail _dot_ com Other: bailey _at_ newman _dot_ upenn _dot_ edu
