From: Trans <transfire@...>
Date: 2007-12-03T06:31:53+09:00
Subject: eruby cutting off top / binding issue

I'm trying to use ERB bound to a controlled context, and it's failing
when it build a template within another template.
If you have any insights about this please let me know. I'm simply at
a loss.

This is a minimal model of the problem I'm having:

  require 'erb'

  class Context

    def initialize(page)
      @page = page
    end

    def render(*a)
      @page.render(*a)
    end

  end

  class Page

    def initialize
      @context = Context.new(self)
      @binding = @context.instance_eval{ binding }
    end

    def in1
      %{
        WAY UP HERE
        <%= render('in2') %>
        WAY DOWN HERE
      }
    end

    def in2
      %{
        RIGHT UP HERE
        <%= render('in3') %>
        RIGHT DOWN HERE
      }
    end

    def in3
      "IN THE MIDDLE"
    end

    def render(var)
      input = eval(var)
      template = ERB.new(input)
      template.result(@binding)
    end

  end

  puts Page.new.render('in1')

I'm getting:

  IN THE MIDDLE
        RIGHT DOWN HERE

        WAY DOWN HERE

Instead of the expected:

      WAY UP HERE

      RIGHT UP HERE
      IN THE MIDDLE
      RIGHT DOWN HERE

      WAY DOWN HERE

Why is it cutting off the top? It makes now sense. If I remove the
context by changing to:

      template.result(binding)

Then it works fine.

T.