From: James Edward Gray II <james@...>
Date: 2005-06-18T00:00:23+09:00
Subject: Re: stubborn program using readline

On Jun 17, 2005, at 9:28 AM, Wybo Dekker wrote:

> What I need is a translation of this simple Perl example into Ruby -
> I think Ruby can't do this:

[snip code]

I think it can:

#!/usr/local/bin/ruby -w

require "readline"
include Readline

lines = ARGF.readlines
puts "#{lines.size} lines."

loop do
     line = readline("Line number:  ", true)

     if line !~ /^\d+$/
         puts "Please enter a positive integer."
     else
         number = line.to_i
         case number
         when 0
             break
         when 1..lines.size
             puts "Line #{number}:  #{lines[number - 1]}"
         else
             puts "No such line."
         end
     end
end

__END__

My run:

$ ruby showlines.rb showlines.rb
25 lines.
Line number:  1
Line 1:  #!/usr/local/bin/ruby -w
Line number:  16
Line 16:                case number
Line number:  17
Line 17:                when 0
Line number:  18
Line 18:                        break
Line number:  1003
No such line.
Line number:  darn
Please enter a positive integer.
Line number:  0

Hope that helps.

James Edward Gray II