class Pry::Pager # @param [String] text # A piece of text to run through a pager. # @param [Symbol?] pager # `:simple` -- Use the pure ruby pager. # `:system` -- Use the system pager (less) or the environment variable # $PAGER if set. # `nil` -- Infer what pager to use from the environment. What this # really means is that JRuby and systems that do not have # access to 'less' will run through the pure ruby pager. def self.page(text, pager = nil) case pager when nil no_pager = !SystemPager.available? is_jruby = defined?(RUBY_ENGINE) && RUBY_ENGINE == "jruby" (is_jruby || no_pager) ? SimplePager.new(text).page : SystemPager.new(text).page when :simple SimplePager.new(text).page when :system SystemPager.new(text).page else raise "'#{pager}' is not a recognized pager." end end def self.page_size 27 end def initialize(text) @text = text end class SimplePager < Pry::Pager def page text_array = @text.lines.to_a text_array.each_slice(Pry::Pager.page_size) do |chunk| puts chunk.join break if chunk.size < Pry::Pager.page_size if text_array.size > Pry::Pager.page_size puts "\n --- Press enter to continue ( q to break ) --- " break if $stdin.gets.chomp == "q" end end end end class SystemPager < Pry::Pager def self.default_pager ENV["PAGER"] || "less -R -S -F -X" end def self.available? pager_executable = default_pager.split(' ').first `which #{ pager_executable }` rescue end def initialize(*) super @pager = SystemPager.default_pager end def page IO.popen(@pager, 'w') do |io| io.write @text end end end end