<%= で自動エスケープ

これを読んで何となく思いついた。
ERBのメソッドを書き換えればどうとでもできるなあ。やりたくないけど。

require 'erb'

class ERB
  class Compiler # :nodoc:
    def compile(s)
      out = Buffer.new(self)

      content = ''
      scanner = make_scanner(s)
      scanner.scan do |token|
        next if token.nil? 
        next if token == ''
        if scanner.stag.nil?
          case token
          when PercentLine
            out.push("#{@put_cmd} #{content_dump(content)}") if content.size > 0
            content = ''
            out.push(token.to_s)
            out.cr
          when :cr
            out.cr
          when '<%', '<%=', '<%#'
            scanner.stag = token
            out.push("#{@put_cmd} #{content_dump(content)}") if content.size > 0
            content = ''
          when "\n"
            content << "\n"
            out.push("#{@put_cmd} #{content_dump(content)}")
            content = ''
          when '<%%'
            content << '<%'
          else
            content << token
          end
        else
          case token
          when '%>'
            case scanner.stag
            when '<%'
              if content[-1] == ?\n
                content.chop!
                out.push(content)
                out.cr
              else
                out.push(content)
              end
            when '<%='
              out.push("#{@insert_cmd}(::ERB::Util.h(#{content}).to_s)")
            when '<%#'
              # out.push("# #{content_dump(content)}")
            end
            scanner.stag = nil
            content = ''
          when '%%>'
            content << '%>'
          else
            content << token
          end
        end
      end
      out.push("#{@put_cmd} #{content_dump(content)}") if content.size > 0
      out.close
      out.script
    end
  end
end

class Foo
  SCRIPT = <<EOS
<h1><%= @name %></h1>
<ul>
<% ary.each do |x|%>
<li><%= x %></li>
<% end %>
</ul>
EOS
  def initialize(name)
    @name = name
    @erb = ERB.new(SCRIPT)
  end

  def foo(ary)
    @erb.result(binding)
  end
end

it = Foo.new('foo')
puts it.foo([1,2,'<dia>'])

~/work$ ruby foo.rb

<h1>foo</h1>

<ul>
<li>1</li>
<li>2</li>
<li>&lt;dia&gt;</li>
</ul>