From: Robert Klemme <shortcutter@...>
Date: 2012-12-20T23:52:17+09:00
Subject: Re: Perl to Ruby: regex captures to assignment.

On Thu, Dec 20, 2012 at 1:38 AM, Derrick B. <lists@ruby-forum.com> wrote:
> First of all, thanks for the fast responses!
>
> Secondly, I swear I tried bracketing the false side of the conditional
> (pg 98, section 4.5.5.3 - "The Ruby Programming Language" book), but I
> remember it assigning the array to the first variable - w.

I would choose a completely different approach: I would have a single
expression for matching and decide which assignments to make based on
the value of one of the capturing groups in the conditional branch:

["1 3/4", "5"].each do |s|
  puts s

  if %r{\A(\d+)(?:\s+(\d+)/(\d+))?\z} =~ s
    w, n, d = $2 ? [$1.to_i, $2.to_i, $3.to_i] : [1, $1.to_i, 0]
    printf "%4d %4d %4d\n", w, n, d
  else
    $stderr.puts "No match #{s}"
  end
end

I also spiced the regexp a bit more to be more restrictive.

> In Perl, there are times when "those brackety thingies" are not
> necessary, but as a programmer, I like readabiliy (yes, still talking
> about Perl :) ) and will include them when it just makes sense.

If you like readability then why are you using Perl in the first place? :-)

Cheers

robert


--
remember.guy do |as, often| as.you_can - without end
http://blog.rubybestpractices.com/