# File lib/rouge/lexers/prometheus.rb, line 11
      def self.functions
        @functions ||= Set.new %w(
          abs absent ceil changes clamp_max clamp_min count_scalar day_of_month
          day_of_week days_in_month delta deriv drop_common_labels exp floor
          histogram_quantile holt_winters hour idelta increase irate label_replace
          ln log2 log10 month predict_linear rate resets round scalar sort
          sort_desc sqrt time vector year avg_over_time min_over_time
          max_over_time sum_over_time count_over_time quantile_over_time
          stddev_over_time stdvar_over_time
        )
      end