class ProgressBar::Format::Molecule

def bar_molecule?
  BAR_MOLECULES.include? key
end

def full_key
  "%#{key}"
end

def initialize(letter)
  self.key         = letter
  self.method_name = MOLECULES.fetch(key.to_sym)
end

def lookup_value(environment, length = 0)
  component = environment.__send__(method_name[0])
  if bar_molecule?
    component.__send__(method_name[1], length).to_s
  else
    component.__send__(method_name[1]).to_s
  end
end

def non_bar_molecule?
  !bar_molecule?
end