Larry Wall <[EMAIL PROTECTED]> 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 $&.
Or the debugger. Or a refactoring tool. Or a Class browser... > So the general declaration should probably be something easy to see > like: > > use STRANGE_SEMANTICS_THAT_SLOW_EVERYONE_DOWN; No question about that. > That will encourage people to be more specific about what they want > to pessimize. Certainly, your fancy module should be encouraged > to declare these things on behalf of its users if it can. I'm not > suggesting that Lukian or Damianly modules force such declarations onto > the users unless it's impossible for the module to know. And it seems > to me that with sufficient control over the user's grammar, you can > often get that information into your own fancy module somehow. > Might take a few macros though, or analysis of the user's code at > CHECK time (or maybe just before). When you say CHECK time, do you mean there'll be a CHECK phase for code that gets required at run time? -- Beware the Perl 6 early morning joggers -- Allison Randal
