From: Stephen Bannasch <stephen.bannasch@...>
Date: 2006-03-24T06:31:35+09:00
Subject: variable substitution in strings read from a file

I have a bunch of template documents which I need to manipulate in 
very simple ways. I'd like to be able to insert Ruby variables into 
the template. Here is a very short example:

file fruit_template.txt: This is a fruit: #{fruit}.

fruit = "apple"
f = IO.read("fruit_template.txt")

Then somehow I'd like to end up with this string:
"This is a fruit: apple."

This works fine of course if I construct the string in Ruby:
s = "This is a fruit: #{fruit}."
=> "This is a fruit: apple."

Thanks for any advice.
-- 
- Stephen Bannasch
   Concord Consortium, http://www.concord.org