An example, flexible Gemfile for puppet

Gemfile.noFeatures

source :rubygems

facter_location = ENV['PUPPET_FACTER']

def type_of(location)
  case location
  when /github/
    :git
  else
    :path
  end
end

def url_of(location)
  if location =~ /(.*)#?/
    $1
  end
end

def branch_of(location)
  if location =~ /.*#(.*)/
    $1
  else
    "master"
  end
end

def source_location_of(location)
  type = type_of(location)
  case type
  when :git
    { :git => url_of(location), :branch => branch_of(location) }
  when :path
    { :path => location }
  else
    raise "Unknown location type: #{type}"
  end
end

gem "rspec", "~> 2.11.0"
gem "mocha", "0.10.5"
gem "rack", "1.1.0"
gem "rake"
gem "ramcrest", source_location_of("https://github.com/hamcrest/ramcrest.git")
gem "facter", "2.0.0", source_location_of(facter_location)