From: Ross Bamford <rosco@...>
Date: 2005-11-28T18:07:29+09:00
Subject: Re: string substitution question

On Mon, 28 Nov 2005 04:28:11 -0000, <ljw1001@gmail.com> wrote:

> I'm reading a file using:
>
>   " str = IO.read("textfile1.txt") "
>
> and trying to output the results using
>
>    " puts str "
> The problem is that I want to substitute values in the file.  It
> includes this text: #{(3+4).to_s}
>
> I expected the puts statement to output 7, but it outputs the code
> literally as #{(3+4).to_s}
>
> How can i get this substitution to happen?
>
> thanks for your help.
>

(Caveat: relatively new to Ruby)

I think it's more trouble than it's worth, though I don't doubt it could  
be done with some insane escaping and eval. I'd have to guess that the #{}  
expansion is done somewhere in the parser (?).

I recently made use of ERB (included with 1.8.3, don't know about other  
versions) for this kind of thing, which worked a treat. Your file would  
contain something like:

	<%= 3+4.to_s %>

(P.s. I know it looks a little bit /.*ML/ but it's not specifically - it's  
just the way ERB separates the code.

-- 
Ross Bamford - rosco@roscopeco.remove.co.uk