From: Niklas Frykholm <r2d2@...>
Date: 2002-02-06T20:41:52+09:00
Subject: Re: expanding variables in strings

[Martin Maciaszek]:
> I have a long list of variables that gets used at several places in
> my program. I figured that it might be a good idea to put the names
> of those variables in an array. So I ended up with the following:
> 
> %w{ foo bar baz}.collect { |x| "'\#{" + x + "}'"}.join(", ")
> --> "'#{foo}', '#{bar}', '#{baz}'"
> 
> This returns a nice string that I would be otherwise cut&pasting all
> over my program. But now I need to expand those variables. I've looked
> up the String class but couldn't find anything useful (except trying
> to rewrite those expensions from scratch)

You could use  eval("%Q{#{str}}")  to eval str as a quoted string
(provided that {} are balanced in the string).

But I would probably rewrite this as a function instead, as below:

	def vars(b)
	  %w{foo bar baz}.collect {|s| "'#{eval(s,b)}'"}.join(', ')
	end

	foo = 3
	bar = 'hallo'
	baz = 'bazzy'
	puts vars(binding)

// Niklas