Re: Syntax of using Perl5 modules?

[Adam Kennedy]

On the migration front, when someone ports Digest.pm to Perl6, I get a 
"free" upgrade, assuming the module author was kind enough to up the 
version number.

You are making a pretty huge assumption here that whoever has a 
namespace in p5 CPAN has first dibs at the P6 namespace of the same 
name, and that they will do a straight port over.

Someone else could reimplement the module for Perl 6, or perhaps the 
author wants to (desperately needed in some cases)completely overhaul 
the module and API based on lessons learnt the first time.

The problem with automatic fallback is simple that you are no longer 
getting two different versions of the same module, you are getting two 
completely different libraries, with no guarentee that the API is 
consistent.

Automatic fallback lets changes in environment leak into the process and 
cause unexpected changes in program functionality, and this is BAD.

The only time at which having to do nothing to load a current CPAN 
module will be during the transition period, before a suffucient body of 
Perl 6 modules have built up.

In the longer run, much better to have to do something special to get 
the old and redundant versions of modules.

Adam K