From: Robert Klemme <shortcutter@...>
Date: 2011-02-09T19:39:43+09:00
Subject: Re: Proposal: String#interpolate for safe templating

On Wed, Feb 9, 2011 at 10:35 AM, Samuel Williams
<space.ship.traveller@gmail.com> wrote:
> Hi,
>
> I'm curious if anyone has considered a method called interpolate:
>
> class String
>        def interpolate(binding, filename, lineno)
>                ... magic ...
>        end
> end
>
> It would have a similar effect as %Q, but the input would already exist as a string rather than being parsed. This would avoid lots of escaping issues. i.e.
>
>        eval("%Q{" + buffer + "}") is fine as long as buffer doesn't contain { or } in the wrong place....

Well, you can do

buffer.gsub(%r<[\#{}]>, '\\\\\\&')

but that is probably not what you want. :-)

> Does this seem useful? I'm personally working on a template system and would find such a function very helpful. Not sure where to start if I was going to implement it - I downloaded the 1.9.2 source code but couldn't really find out where I'd add the code.

I am not sure I understand how that would resolve your escaping
problem: the method in question cannot know whether you want specific
characters (namely #{ and }) as they are or as meta characters.  Am I
missing something?

Kind regards

robert

-- 
remember.guy do |as, often| as.you_can - without end
http://blog.rubybestpractices.com/