class Bundler::RubyVersion

def initialize(versions, patchlevel, engine, engine_version)
  # The parameters to this method must satisfy the
  # following constraints, which are verified in
  # the DSL:
  #
  # * If an engine is specified, an engine version
  #   must also be specified
  # * If an engine version is specified, an engine
  #   must also be specified
  # * If the engine is "ruby", the engine version
  #   must not be specified, or the engine version
  #   specified must match the version.
  @versions = Array(versions).map do |v|
    op, v = Gem::Requirement.parse(normalize_version(v))
    op == "=" ? v.to_s : "#{op} #{v}"
  end
  @gem_version        = Gem::Requirement.create(@versions.first).requirements.first.last
  @input_engine       = engine&.to_s
  @engine             = engine&.to_s || "ruby"
  @engine_versions    = (engine_version && Array(engine_version)) || @versions
  @engine_gem_version = Gem::Requirement.create(@engine_versions.first).requirements.first.last
  @patchlevel         = patchlevel || (@gem_version.prerelease? ? "-1" : nil)
end