erblock.rb

require 'erb'

class MyERB < ERB
  class CompilerWithBlock < ERB::Compiler
    def add_put_cmd(out, content)
      out.push("#{@put_cmd} #{content_dump(content)}")
    end

    BLOCK_EXPR = /\s+(do|\{)(\s*\|[^|]*\|)?\s*\Z/    
    def add_insert_cmd(out, content)
      if BLOCK_EXPR =~ content
        out.push("#{@insert_cmd} #{content}")
      else
        out.push("#{@insert_cmd}((#{content}).to_s)")
      end
    end
  end
    
  def make_compiler(*args)
    CompilerWithBlock.new(*args)
  end

  def set_eoutvar(compiler, eoutvar = '_erbout')
    compiler.put_cmd = "#{eoutvar}.concat"
    compiler.insert_cmd = "#{eoutvar} << "
    compiler.pre_cmd = ["#{eoutvar} = ''"]
    compiler.post_cmd = [eoutvar]
  end
end

if __FILE__ == $0
  rhtml = <<EOS
<%= (1..10).find_all do |n| %>
  <%= n %>
  <% n % 2 == 0 
end.join %>
EOS

  puts MyERB.new(rhtml).src
  MyERB.new(rhtml).def_method(Kernel, 'hoge')
  
  puts hoge
end