Can't get eval to reference $1, $2, etc

ruby-talk
1

Ok, so I have this array of pairs that control file movements, for organizing directory trees. It looks something like this:

    rules = [
       ['(.+).tgz', 'tars/$1'],
       ['(.+)-(.+).war', '$1/webapps/$2'],
       # and so on...
    ]

Then, I want to iterate through these, capturing the regex matches and using them in the paths on the right side of the hash. I have something like this:

    file = 'abc.tgz' # just for example
    dest = ''
    rules.each do |row|
      if file =~ %r{^#{row[0]}$}
        eval "dest = \"#{row[1]}\"" # XXX broken: want to ref matches
        break
      end
    end
    puts dest # "tars/$1", instead of "tars/abc"

The problem is, I can't get the matches to show up inside the eval. I've tried %Q, different quote combinations, etc. Anyone know a way to make this work?

Thanks,
Nate

P.S. Ruby 1.8.4 on CentOS 4

2

Answered my own question (of course)... here's a way to do this by using sub instead of match/eval, which is much safer too:

     path = file.dup
     rules.each do |row|
       dest = row[1] || ''
       dest.gsub!('$','\\') # allow $Perl or \Sed markers
       if path.sub!(%r{^#{row[0]}$}, dest)
         return path
       end
     end

-Nate