class Gem::Requirement

def self.create(*inputs)
  return new inputs if inputs.length > 1
  input = inputs.shift
  case input
  when Gem::Requirement then
    input
  when Gem::Version, Array then
    new input
  when '!' then
    source_set
  else
    if input.respond_to? :to_str
      new [input.to_str]
    else
      default
    end
  end
end

def self.default
  new '>= 0'
end

def self.default_prerelease
  new '>= 0.a'
end

def self.parse(obj)
  return ["=", obj] if Gem::Version === obj
  unless PATTERN =~ obj.to_s
    raise BadRequirementError, "Illformed requirement [#{obj.inspect}]"
  end
  if $1 == ">=" && $2 == "0"
    DefaultRequirement
  elsif $1 == ">=" && $2 == "0.a"
    DefaultPrereleaseRequirement
  else
    [-($1 || "="), Gem::Version.new($2)]
  end
end

def self.source_set # :nodoc:
  SOURCE_SET_REQUIREMENT
end

def ==(other) # :nodoc:
  return unless Gem::Requirement === other
  # An == check is always necessary
  return false unless _sorted_requirements == other._sorted_requirements
  # An == check is sufficient unless any requirements use ~>
  return true unless _tilde_requirements.any?
  # If any requirements use ~> we use the stricter `#eql?` that also checks
  # that version precision is the same
  _tilde_requirements.eql?(other._tilde_requirements)
end

def _sorted_requirements
  @_sorted_requirements ||= requirements.sort_by(&:to_s)
end

def _tilde_requirements
  @_tilde_requirements ||= _sorted_requirements.select {|r| r.first == "~>" }
end

def as_list # :nodoc:
  requirements.map {|op, version| "#{op} #{version}" }
end

def concat(new)
  new = new.flatten
  new.compact!
  new.uniq!
  new = new.map {|r| self.class.parse r }
  @requirements.concat new
end

def encode_with(coder) # :nodoc:
  coder.add 'requirements', @requirements
end

def exact?
  return false unless @requirements.size == 1
  @requirements[0][0] == "="
end

def fix_syck_default_key_in_requirements # :nodoc:
  Gem.load_yaml
  # Fixup the Syck DefaultKey bug
  @requirements.each do |r|
    if r[0].kind_of? Gem::SyckDefaultKey
      r[0] = "="
    end
  end
end

def for_lockfile # :nodoc:
  return if [DefaultRequirement] == @requirements
  list = requirements.sort_by do |_, version|
    version
  end.map do |op, version|
    "#{op} #{version}"
  end.uniq
  " (#{list.join ', '})"
end

def hash # :nodoc:
  requirements.sort.hash
end

def init_with(coder) # :nodoc:
  yaml_initialize coder.tag, coder.map
end

def initialize(*requirements)
  requirements = requirements.flatten
  requirements.compact!
  requirements.uniq!
  if requirements.empty?
    @requirements = [DefaultRequirement]
  else
    @requirements = requirements.map! {|r| self.class.parse r }
  end
end

def marshal_dump # :nodoc:
  fix_syck_default_key_in_requirements
  [@requirements]
end

def marshal_load(array) # :nodoc:
  @requirements = array[0]
  fix_syck_default_key_in_requirements
end

def none?
  if @requirements.size == 1
    @requirements[0] == DefaultRequirement
  else
    false
  end
end

def prerelease?
  requirements.any? {|r| r.last.prerelease? }
end

def pretty_print(q) # :nodoc:
  q.group 1, 'Gem::Requirement.new(', ')' do
    q.pp as_list
  end
end

def satisfied_by?(version)
  raise ArgumentError, "Need a Gem::Version: #{version.inspect}" unless
    Gem::Version === version
  # #28965: syck has a bug with unquoted '=' YAML.loading as YAML::DefaultKey
  requirements.all? {|op, rv| (OPS[op] || OPS["="]).call version, rv }
end

def specific?
  return true if @requirements.length > 1 # GIGO, > 1, > 2 is silly
  not %w[> >=].include? @requirements.first.first # grab the operator
end

def to_s # :nodoc:
  as_list.join ", "
end

def to_yaml_properties # :nodoc:
  ["@requirements"]
end

def yaml_initialize(tag, vals) # :nodoc:
  vals.each do |ivar, val|
    instance_variable_set "@#{ivar}", val
  end
  Gem.load_yaml
  fix_syck_default_key_in_requirements
end