From: "Jesús Gabriel y Galán" <jgabrielygalan@...>
Date: 2012-12-04T21:00:56+09:00
Subject: Re: What is wrong in this

On Tue, Dec 4, 2012 at 12:45 PM, Mallikarjuna Yaddala
<lists@ruby-forum.com> wrote:
> $rr_msg = "hello"
>
> task :default do
>         display "rr"
> end
>
> def display(msg)
>         ss = msg+"_msg"
>         puts "#{$ss}"
> end
>
>
> My aim is to construct a global var ($rr_msg) and get the value ...

You can't construct a variable like that. In order to do this you need
to use eval:

1.9.2p290 :001 > $rr_msg = "test"
 => "test"
1.9.2p290 :002 > var = "rr"
 => "rr"
1.9.2p290 :004 > eval "$#{var}_msg"
 => "test"

But there's another way. Instead of constructing a variable, you could
create a hash whose keys are the "variables":

$messages = {"rr" => "test"} # not sure it needs to be global, but whatever

def display message_id
  puts $messages[message_id]
end

display "rr"  #=> test

Jesus.