class Pry::Pager::SystemPager

`SystemPager` buffers output until we're pretty sure it's at least a page long, then invokes an external pager and starts streaming output to it. If `#close` is called before then, it just prints out the buffered content.

Public Class Methods

available?() click to toggle source
# File lib/pry/pager.rb, line 142
def self.available?
  if @system_pager.nil?
    @system_pager =
      begin
        pager_executable = default_pager.split(' ').first
        if Helpers::Platform.windows? || Helpers::Platform.windows_ansi?
          `where /Q #{pager_executable}`
        else
          `which #{pager_executable}`
        end
        $CHILD_STATUS.success?
      rescue StandardError
        false
      end
  else
    @system_pager
  end
end
default_pager() click to toggle source
# File lib/pry/pager.rb, line 130
def self.default_pager
  pager = Pry::Env['PAGER'] || ''

  # Default to less, and make sure less is being passed the correct
  # options
  pager = "less -R -F -X" if pager.strip.empty? || pager =~ /^less\b/

  pager
end
new(*) click to toggle source
Calls superclass method Pry::Pager::NullPager::new
# File lib/pry/pager.rb, line 161
def initialize(*)
  super
  @tracker = PageTracker.new(height, width)
  @buffer  = ""
  @pager   = nil
end

Public Instance Methods

close() click to toggle source
# File lib/pry/pager.rb, line 181
def close
  if invoked_pager?
    pager.close
  else
    @out.puts @buffer
  end
end
write(str) click to toggle source
# File lib/pry/pager.rb, line 168
def write(str)
  if invoked_pager?
    write_to_pager str
  else
    @tracker.record str
    @buffer += str

    write_to_pager @buffer if @tracker.page?
  end
rescue Errno::EPIPE
  raise StopPaging
end

Private Instance Methods

invoked_pager?() click to toggle source
# File lib/pry/pager.rb, line 195
def invoked_pager?
  @pager
end
pager() click to toggle source
# File lib/pry/pager.rb, line 199
def pager
  @pager ||= IO.popen(self.class.default_pager, 'w')
end
write_to_pager(text) click to toggle source
# File lib/pry/pager.rb, line 191
def write_to_pager(text)
  pager.write @out.decolorize_maybe(text)
end