# File lib/yard/rubygems/hook.rb, line 47
    def self.generation_hook(installer, specs)
      start = Time.now
      types = installer.document

      generate_yard = types.include?('yardoc') || types.include?('yard')
      generate_yri = types.include? 'yri'

      specs.each do |spec|
        gen_yard, gen_yri = generate_yard, generate_yri
        gen_yri = false if gen_yard # never generate both, no need
        if types.size > 0 # --no-document is not in effect
          # look at spec.metadata['yard.run'] for override
          run_yard = spec.metadata['yard.run']
          gen_yard = true if run_yard && run_yard != 'yri'
          gen_yri = true if run_yard == 'yri'
        end

        new(spec, gen_yard, gen_yri).generate
      end

      return unless generate_yard or generate_yri

      duration = (Time.now - start).to_i
      names = specs.map(&:name).join ', '

      say "Done installing documentation for #{names} after #{duration} seconds"
    end