On 22 avr. 09, at 16:43, David Masover wrote:

> On Tuesday 21 April 2009 09:48:47 Robert Dober wrote:
>> On Tue, Apr 21, 2009 at 4:39 PM, James Herdman  
>> <james.herdman / gmail.com>
>
>> Installing Ruby1.8 and Ruby1.9 on the same machine is a major pain.
>
> It really wasn't, for me. The easiest way is to simply give the  
> executables a
> suffix -- irb1.9 vs irb. And I don't know that typing "irb1.9" is  
> harder than
> "jruby --1.9".
>

Probably the installation difference is minor if you just want to  
learn and experiment.   It's more of an issue if you seriously want  
to adopt ruby 1.8 and 1.9 on many machines, different platforms, and  
critical applications.   Then you have to be more careful with Ruby  
1.8 and 1.9.   Different package managers and installers are going to  
give you different snapshots.    You'll want to be sure you have some  
kind of system in place for managing, updating and backing off all  
the different permutations so that your apps will be reliable.

If Ruby 1.8 and 1.9 source came in a version control system such that  
it was quick and easy to retrieve specific versions that would  
probably help a lot.   Then you could try various versions without  
worrying too much if there are any issues and you could probably give  
good specific information about problems to ruby developers so they  
can fix them.