From: Ross Bamford <rosco@...>
Date: 2005-11-29T06:22:30+09:00
Subject: Re: string substitution question

On Mon, 28 Nov 2005 12:00:37 -0000, <ljw1001@gmail.com> wrote:

> What is ERB?
>
> I had assumed that it would be possible to convert a single quote
> string to a double quote string and that would take care of it.  Is
> that not possible. Maybe I'm looking at this the wrong way.
> Substitution is done with the syntax you mention in my current version
> of Rails.  Is ERB what they use?
>

It is probably possible, maybe using the special quoting operators and so  
forth, but I imagine it is messy and problematic (?).
There appears to be some automagic escaping going on when # is read into  
double quoted strings, or something like that.
Rails does use ERB, and I think I'd still suggest it. It's 'Embedded  
Ruby'. With 1.8 it comes as standard (at least with 1.8.3). You can use it  
like:

   require 'erb'

   sturf = ['just', 'some', 'stuff']
   src = "<% sturf.length.times do |i| %><%= sturf[i] %> <% end %>"

   text = ERB.new(src).result       # => "just some stuff "

You can pass a binding to the 'result' method, so that you can do the  
following:

   require 'erb'
   class SomeClazz

     def set_some_var
       @foo = 'bar'
       self
     end

     def render_text(s)
       ERB.new(s).result(binding)
     end
   end

   s = SomeClazz.new.set_some_var.render_text('<%= @foo %>')  # => "bar"

There is also a native version of ERB as a command - try 'erb' at your  
prompt (I found it's -x option quite helpful when debugging template  
problems).

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