Larry Wall writes: > On Tue, Dec 16, 2003 at 07:05:19AM -0700, Luke Palmer wrote: > : Michael Lazzaro writes: > : > > : > On Sunday, December 14, 2003, at 06:14 PM, Larry Wall wrote: > : > >But the agreement could be implied by silence. If, by the time the > : > >entire program is parsed, nobody has said they want to extend an > : > >interface, then the interface can be considered closed. In other > : > >words, if you think you *might* want to extend an interface at run > : > >time, you'd better say so at compile time somehow. I think that's > : > >about as far as we can push it in the "final" direction. > : > > : > That seems a very fair rule, especially if it adds a smidge more speed. > : > Runtime extension will likely be very unusual > : > : Unless you're me. Or Damian. Or a fair number of other programmers who > : like to dive into the Perl Dark Side on a regular basis. > : > : > -- requiring it to be explicit seems reasonable. > : > : It seems so. Knowing Larry, I'm sure this is an ungrounded fear, but I > : definitely want to be able to declare in a module "I'm going to be > : screwing with stuff; keep out of my way," so that I don't impose any > : awkward declarations on my module users. If that request can be made > : more explicit in the cases where that's possible, great, but the general > : declaration should be available. > > Okay, we'll call the general declaration: > > use $& > > or some such. :-) > > Seriously, I hope we can provide a framework in which you can screw > around to your heart's content while modules are being compiled, > and to a lesser extent after compilation. But we'll never get to a > programming-in-the-large model if we can't limit most of the screwing > around to the lexical scope currently being compiled, or at least > to a known subset of the code. Modules that turn off optimization > for all other modules are going to be about as popular as $&. So > the general declaration should probably be something easy to see like: > > use STRANGE_SEMANTICS_THAT_SLOW_EVERYONE_DOWN;
Hmm, I guess that's true. A module author shouldn't have the the freedom to say that his classes are completely untouchable, because he doesn't know what you're going to be doing with them. But correspondingly, I guess, a module author shouldn't have the freedom to slow everybody down because he was lazy about figuring out what needed to be declared "open". But Perl hinges on laziness, doesn't it? Eh, I trust that Perl 6 will make it easy to figure that out in most cases. I was coming from the perspective that 90% of my projects don't need speed; but I can say no such thing on account of my users. And what about that un-accounted-for 10%? Perhaps the real detterent to using such a thing would be making it generate a warning when -w is on. You get the peer pressure thing; people frown upon you when you use the pragma unwisely. So, yeah, I agree with you now. Luke
