I would be dismayed if the solution reached meant that Perl 5 barfed with an odd error - if any Perl 6 program needs to be Perl 5 before Perl 6 is 'switched on', then I would think that the switch should be something that causes an obvious error in Perl 5 when run, so that the user knows that it is Perl 6 code. For example:

$ perl
use 6.0;
Perl v6.0.0 required (did you mean v6.000?)--this is only v5.8.1, 
stopped at - line 1.

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To me, that looks fine. To have some kind of 'module Main;' requirement (as per Larry's last sentance) you get: 

$ perl
module Main;
Can't locate object method "module" via package "Main" (perhaps you 
forgot to load "Main"?) at - line 1.

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That just looks like something has broken. But, although 'use 6.0;' looks okay, it kinda fails the EXTEND test he sets out - it's not naturally there. In fact, I don't think there is anything naturally there in a Perl 5 program that you can use to do this. But, maybe Larry only raised that point in relation to modules.

In reply to Re: Re: Ensuring forward compatibility by kal
in thread Ensuring forward compatibility by DrHyde

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