ignored_modules

# File lib/irb/completion.rb, line 213
    def self.ignored_modules
      # We could cache the result, but this is very fast already.
      # By using this approach, we avoid Module#name calls, which are
      # relatively slow when there are a lot of anonymous modules defined.
      s = {}

      scanner = lambda do |m|
        next if s.include?(m) # IRB::ExtendCommandBundle::EXCB recurses.
        s[m] = true
        m.constants(false).each do |c|
          value = m.const_get(c)
          scanner.call(value) if value.is_a?(Module)
        end
      end

      %(IRB SLex RubyLex RubyToken).each do |sym|
        next unless Object.const_defined?(sym)
        scanner.call(Object.const_get(sym))
      end

      s.delete(IRB::Context) if defined?(IRB::Context)

      s
    end