From: Ross Bamford <rossrt@...>
Date: 2006-03-25T18:49:20+09:00
Subject: Re: require a certain version of the ruby interpreter

On Sat, 2006-03-25 at 11:06 +0900, dblack@wobblini.net wrote:
> Hi --
> 
> On Sat, 25 Mar 2006, Robert Klemme wrote:
> 
> > Shea Martin wrote:
> >> This works nicely, but I am sure something like this is already built in, 
> >> but I can't seem to find it.
> >> 
> >> def require_version( p_ver_str )
> >>   l_have = VERSION.split('.')
> >>   l_need = p_ver_str.split('.')
> >>   l_need.each_index do |i|
> >>     if l_have[i].to_i < l_need[i].to_i
> >>       raise ScriptError, "Required Ruby #{p_ver_str}, found Ruby 
> >> #{VERSION}"
> >>     end
> >>   end
> >> end
> >
> > Hmmm, lettsee whether we can compress that a bit. How about:
> >
> > def ensure_version(ver)
> >  raise "Requiring at least #{ver}" unless
> >    RUBY_VERSION.scan(/d+/).map! {|x|x.to_i} >=
> >       ver.scan(/d+/).map! {|x|x.to_i}
> > end
> >
> > Not really a one liner...
> 
> (What, no inject? :-)  I don't think Array has >= though.

:) Even I couldn't find an excuse for inject on this one. The best I
could do was:

def ensure_version(v)
  raise "need #{v}" if VERSION.split('.').zip(v.split('.')).any? {|a,b| a < b}
end

(given that we don't need to worry about two-digit versions of course).

-- 
Ross Bamford - rosco@roscopeco.REMOVE.co.uk