First of all, the least version for which this will apply is 5.16. And that's assuming it can be build before that.

But really, what's is the purpose of saying "I need Perl 5.xx or higher"? The entire point of this exercise is to be able to remove features without breaking. The fact that use 5.006; means "I want lexical filehandles" means we have to support lexical filehandles forever, in the same as it's now.

Say, in 5.20 we have a really awesome feature. You get it with use 5.20;. But a year and a half later, it turns out the feature wasn't so awesome, or it can be made better, but only in a way to break backwards compatibility, Jesse's proposal makes it possible. use 5.20; and use 5.22; will give you the awesome feature, use 5.24; won't, or with a changed syntax and/or semantics.

But if people can say "use 5.20 or something newer", it's not going to work. Then we're back to the same backwards compatibility issues we have right now.

Note that Jesse's proposal doesn't imply that use 5.20; means it's going to croak on 5.22 or 5.24. Not at all. It means that 5.22 or 5.24 is going to emulate the 5.20 behaviour.

In reply to Re^3: Back to the __future__ by JavaFan
in thread Back to the __future__ by cdarke

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