From: dblack@...
Date: 2006-03-25T21:42:26+09:00
Subject: Re: require a certain version of the ruby interpreter

Hi --

On Sat, 25 Mar 2006, Pit Capitain wrote:

> dblack@wobblini.net schrieb:
>> Here's yet another variation on the theme.  (I thought I'd posted this
>> in my previous post but I didn't.)
>> 
>> require 'scanf'
>> def ensure_version(need)
>>   need.scanf("%d.%d.%d").
>>        zip(RUBY_VERSION.scanf("%d.%d.%d")).any? do |a,b|
>>     a > b
>>   end and raise "Requires at least #{need}"
>> end
>
> Both the solutions using any? aren't correct:
>
>  puts RUBY_VERSION       # => 1.8.4
>  ensure_version "1.6.8"  # => Requires at least 1.6.8 (RuntimeError)

Whoops.  I guess the order matters: one would want to peel off numbers
from the left until there's an inequal pair.

I've gone back to feeling lazy enough to piggy-back on the assurance
of one digit per field:

def ensure_version(need)
   raise "Requires ruby #{need}" if need < RUBY_VERSION
end


David

-- 
David A. Black (dblack@wobblini.net)
Ruby Power and Light, LLC (http://www.rubypowerandlight.com)

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