Rails form helper for mustache spike/proof of concept

edit.html.mustache

<!-- A scaffolded edit view converted to mustache -->

<h1>Editing post</h1>

{{#form}}
  {{#errors?}}
    <div id="error_explanation">
      <h2>{{error_header}}</h2>
    </div>
    <ul>
      {{#errors}}
        <li>{{.}}</li>
      {{/errors}}
    </ul>
  {{/errors?}}

  <div class="field">
    {{title_label}}<br />
    {{title_input}}
  </div>
  <div class="field">
    {{body_label}}<br />
    {{body_input}}
  </div>
  <div class="field">
    {{author_label}}<br />
    {{author_input}}
  </div>
  <div class="actions">
    {{submit}}
  </div>
{{/form}}

{{{show_link}}}
{{{back_link}}}

edit.rb

require "mustache_extras"

class Posts::Edit < Mustache::Rails
  include Mustache::FormBuilder
  
  def form
    formable(@post) do |f|
      {
        :title_label  => f.label(:title),
        :title_input  => f.text_field(:title),
        :body_label   => f.label(:body),
        :body_input   => f.text_area(:body),
        :author_label => f.label(:author),
        :author_input => f.text_field(:author),
        :submit       => f.submit
      }
    end
  end
  
  def errors?
    @post.errors.any?
  end
  
  def error_header
    "#{pluralize(@post.errors.count, "error")} prohibited this post from being saved:"
  end
  
  def errors
    @post.errors.full_messages
  end
  
  def show_link
    link_to 'Show', @post
  end
  
  def back_link
    link_to 'Back', posts_path
  end
  
end

mustache_extras.rb

module Mustache::FormBuilder
  def formable(object)
    lambda do |text|
      form_for(object) do |f|
        obj = FormableMustache.new(yield(f))
        Mustache.render(text, obj).html_safe
      end
    end
  end
end

class FormableMustache < Mustache
  def initialize(data)
    data.each_pair do |key, value|
      FormableMustache.send(:define_method, key, proc{value})
    end
  end
  
  def escapeHTML(str)
    str
  end
end