From: Lloyd Zusman <ljz@...>
Date: 2005-03-03T09:33:00+09:00
Subject: Re: Erb: terminating a script?

Jamis Buck <jamis_buck@byu.edu> writes:

> On Mar 2, 2005, at 4:02 PM, Lloyd Zusman wrote:
>
>> [ ... ]
>>     res.body = evaluate(ERB.new('<% lambda { %>' +
>>                                 data +
>>                                 '<% }.call %>'),
>>                         req, res)
>>
>> In this case, I can exit early by using either '<% break %>' or
>> '<% return %>'.  I like this one better, and this is what I have
>> just now implemented in my application.
>
> Excellent work, Lloyd. Thanks for sharing!

Well, I'm just glad to have found a solution, and I hope that it's
helpful to others.


>> Because of this, it seems to me that it would be beneficial if Erb were
>> to always put a lambda-call block around the text that gets evaluated.
>>
>> I'm in favor of this enhancement going into a subsequent release, and
>> I'll soon submit a patch.
>>
>> Thoughts or opinions?
>
> I'd vote for it. :)

OK.  Here it is.  Unless or until this becomes a bona-fide Erb
enhancement, just put this code snippet in your application, somewhere
after the "require 'erb'" statement:

class ERB
  def result(b=TOPLEVEL_BINDING)
    # Enclosing the 'eval' in a 'lambda-call' block allows it
    # to be cut short by means of a 'break' or 'return'.
    if @safe_level
      th = Thread.start {
        $SAFE = @safe_level
        lambda {
          eval(@src, b, (@filename || '(erb)'), 1)
        }.call
      }
      return th.value
    else
      return lambda {
        eval(@src, b, (@filename || '(erb)'), 1)
      }.call
    end
  end
end



-- 
 Lloyd Zusman
 ljz@asfast.com
 God bless you.