Larry Wall writes: > On Thu, Mar 08, 2007 at 09:05:32AM +0000, Smylers wrote: > > : So I fear that people will do the same thing in Perl 6. Which, > : initially, will appear to work. But then, some months later, > : somebody upgrades the installed version of a module (or the program > : gets deployed on another computer, which happens to have a more > : recent version installed), and suddenly the program will break. > > Nope, check your assumptions, you've got a big one that just ain't so. > Perl 6 is specced to keep all the old versions of modules around in > the library
Yeah, that's why I added "or the program gets deployed on another computer, which happens to have a more recent version". > (unless the new version claims to emulate the old version). So an > upgrade doesn't generally break fixed dependencies. Aha! So even if I specify that I want, say, version 1.3, if only version 1.6 is installed but the module's author claims never to've broken backwards compatibility then it will run anyway? That's good. > : * In many (most?) cases the breakage will be arbitrary, in that the > : module would've worked fine had it been allowed to run rather than > : being stopped by the version-checker. > > It is allowed to run anyway, Sorry, I don't quite understand that. What does happen if a program requests a version of a module that > : * It's a change from what was good practice in Perl 5. > > s/good/common/; I'd say that common practice in Perl 5 is merely to use a module and not specify a version number at all! Specifying a minimum version number is an improvement -- obviously not ideal, but it is as much as can be done straightforwardly with Perl 5. And I think it'very likely people in the habit of doing this in Perl 5 will, at least initially, specify a single version number in Perl 6 C<use> lines. > Those who believe the stagnation of Perl 5 is caused by Perl 6 should > go back and reread the 361 RFCs ... <Snip> Sorry if my post came across as some kind of attack on Perl 6 as a whole -- it certainly wasn't supposed to be!! I'm very much in favour of the way Perl 6 is going and the many improvements it brings. (And I'm not sure what stagnation has to do with this thread, but for what it's worth I think quite the opposite: Perl 6 has been the inspiration for several good things people are already doing with Perl 5.) Cheers. Smylers
