gistfile1.rb

class Hash
  def lookup_path(query)
    path = query.split('.')

    path.inject(self) do |result, key|
      result[key] or return nil # || won't work.
    end
  end
end

begin
  require "spec"
rescue LoadError
  require "rubygems"
  require "spec"
end

describe Hash, "#lookup_path" do
  before(:each) do
    @hash = {"dev" => {"server" => {"name" => "thor"}}}
  end

  it "should dive deep into the hash" do
    @hash.lookup_path("dev.server").should == {"name" => "thor"}
    @hash.lookup_path("dev.server.name").should == "thor"
  end

  it "should not care if the keys are strings or symbols" do
    {"dev" => "foo"}.lookup_path("dev").should == "foo"
  end

  it "should return nil for a unknown first level key" do
    {"dev" => "foo"}.lookup_path("test").should be_nil
  end

  it "should return nil for a unknown second level key" do
    {"dev" => "foo"}.lookup_path("test.foo").should be_nil
  end
end