class String

# File lib/ext/string.rb, line 7
def constantize
  names = split('::')

  # Trigger a built-in NameError exception including the
  # ill-formed constant in the message.
  Object.const_get(self) if names.empty?

  # Remove the first blank element in case of '::ClassName' notation.
  names.shift if names.size > 1 && names.first.empty?

  names.inject(Object) do |constant, name|
    if constant == Object
      constant.const_get(name)
    else
      candidate = constant.const_get(name)
      next candidate if constant.const_defined?(name, false)
      next candidate unless Object.const_defined?(name)

      # Go down the ancestors to check if it is owned directly. The check
      # stops when we reach Object or the end of ancestors tree.
      constant = constant.ancestors.inject do |const, ancestor|
        break const    if ancestor == Object
        break ancestor if ancestor.const_defined?(name, false)
      end

      # owner is in Object, so raise
      constant.const_get(name, false)
    end
  end
end