Working sketch of Rails i18n syntax for more easily passing in formatted (in your templating language) values, and also using multiple keys under the same scope (which is a good idea). Also see [a previous sketch with similar ideas](https://gist.github.com/henrik/4605425).

1. page.slim

= t_scope(:"my.example.text") do |scope|
  - scope.world do
    span.worldly= my_world_helper
  - scope.sign_up do
    = link_to(scope.t(:sign_up), sign_up_path)
  - scope.log_in do
      = link_to(scope.t(:log_in), log_in_path)

2. en.yml

en:
  my:
    example:
      text: "Hello %{world}! Please %{sign_up} or %{log_in}!"
      sign_up: "sign up"
      log_in: "log in"

3. i18n_helper.rb

module I18nHelper
  class Scope
    def initialize(base_key, helper)
      @base_key = base_key
      @helper = helper
      @hash = {}
    end

    def to_hash
      hash
    end

    def t(key, opts = {})
      helper.t("#{base_key}.#{key}", opts)
    end

    def method_missing(name, *args, &block)
      html = helper.capture(&block)
      hash[name] = html
    end

    private

    attr_reader :base_key, :helper, :hash
  end

  def t_scope(key)
    base_key = key.to_s.rpartition(".").first
    scope = Scope.new(base_key, self)
    yield(scope)
    t(key, scope.to_hash).html_safe
  end
end

4. i18n_helper_spec.rb

require "spec_helper"
require "i18n_helper"

describe I18nHelper do
  let(:view) { double.extend(described_class) }

  # Not very integrated, but request tests will do that.
  describe "#t_scope" do
    it "can abbreviate scopes" do
      view.should_receive(:t).with("foo.bar.text", {}).
        and_return("whatever")
      view.should_receive(:t).with("foo.bar.baz", two: 2)

      view.t_scope("foo.bar.text") do |scope|
        scope.t(:baz, two: 2)
      end
    end

    it "can capture and interpolate view blocks" do
      view.stub(:capture) { |&block| block.call }
      view.should_receive(:t).with("foo.hello", world: "a view").
        and_return("whatever")

      view.t_scope("foo.hello") do |scope|
        scope.world do
          "a view"
        end
      end
    end
  end
end