Side-by-side fields for formtastic-bootstrap

formtastic.rb

# config/initializers/formtastic.rb
module FormtasticBootstrap
  class FormBuilder < Formtastic::FormBuilder

    # Allow "split-field" inputs such as name (first+last) or location (city+state).
    # Block contents are wrapped in a ".controls" field set next to the specified
    # +label+
    #
    # Usage:
    #
    #    <%= f.split_fields 'Name' do %>
    #      <%= f.text_field :first_name, :placeholder => 'First', :style => 'width:80px' %>
    #      <%= f.text_field :last_name, :placeholder => 'Last', :style => 'width:100px' %>
    #    <% end %>
    #
    def split_fields(label, &block)
      if block_given?
        controls = template.capture(&block)

        label = template.content_tag :div, label, :class => 'control-label'
        controls = template.content_tag :div, controls, :class => 'controls'
        template.content_tag(:div, label + controls, :class => 'control-group')
      end
    end
  end
end

Formtastic::Helpers::FormHelper.builder = FormtasticBootstrap::FormBuilder

Using Rails' flat form builder is not the most OO-approach, but it fits the bill for a quick+dirty!