From: Kristof Bastiaensen <kristof@...>
Date: 2004-04-23T23:24:13+09:00
Subject: Re: find a best version (of a package)

On Fri, 23 Apr 2004 21:17:14 +0900, saiph wrote:

> 
> hi list,
> 
> 
> i'm following the "learning ruby" path, i've found this list very usefull the 
> last time (tnx), so i thought to send this simple example to better 
> understand what'd to be a good programming style.
> 
> 
> 
> alea> expand -t 2 best_vv
> -----------------------------------------------
> class String
> def newer?(s)
>   b = self.dup
> 
>   b.sub!(/(\w+-)/, '')
>   t = $+
>   s.sub!(/(\w+-)/, '')
> 
>   return -1 if t != $+  # not the same package
> 
>   while (b.sub!(/(\d+\.|\d+)/, '')) do
>     t = $+.chomp('.')
>     s.sub!(/(\d+\.|\d+)/, '')
> 
>     return 1 if $+ == nil
>     return 1 if t.to_i > $+.chomp('.').to_i
>   end
> 
>   return 0
> end
> end
> 
> class Array
> def best_version?
>   s = 0
> 
>   for i in 1..self.length() - 1 do
>     t = self[i].newer? self[s]
>     if t == 1
>       s = i
>     elsif t == -1
>       return nil
>     end
>   end
> 
>   return s
> end
> end
> 
> vv = ['ruby-2.2.5', 'ruby-3.2.6', 'ruby-5']
> i = vv.best_version?
> puts vv[i]
> -----------------------------------------------
> 
> how would you write or change this?
> 
> 
> tnx again for your time :)
> 
> best regards,
> saiph

My try:

r = /ruby-([\d.]+)/
['ruby-2.2.5', 'ruby-3.2.6', 'ruby-5'].max { |a, b|
  r.match(a)[1].split(".") <=> r.match(b)[1].split(".") }

or shorter:

['ruby-2.2.5', 'ruby-3.2.6', 'ruby-5'].sort_by { |s|
  /ruby-([\d.]+)/.match(s)[1].split(".") }[-1]

(I am not sure which one performs the best).

My opinion about programming style is:  make things as
simple as you can.  Don't create extra helper classes
etc if you don't need them.

Kristof