Bleything's IRB history hacks

gistfile1.txt

# Ben Bleything's IRB history hacks
# from RubyConf 2007, 2-4 November

# Lists the last how_many lines of history (defaults to 50).  Aliased to h.
def history( how_many = 50 )
  history_size = Readline::HISTORY.size

  # no lines, get out of here
  puts "No history" and return if history_size == 0

  start_index = 0

  # not enough lines, only show what we have
  if history_size <= how_many
    how_many  = history_size - 1
    end_index = how_many
  else
    end_index = history_size - 1 # -1 to adjust for array offset
    start_index = end_index - how_many 
  end

  start_index.upto( end_index ) {|i| print_line i}
  nil
end
alias :h  :history


# replay lines from history.  Aliased to h!
#
# h! by itself will replay the most recent line.  You can also pass in a
# range, array, or any mixture of the three.
#
# We subtract 2 from HISTORY.size because -1 is the command we just issued.
def history_do( *lines )
  lines = [Readline::HISTORY.size - 2] if lines.empty?

  to_eval = get_lines( lines )

  to_eval.each {|l| Readline::HISTORY << l}

  IRB.CurrentContext.workspace.evaluate self, to_eval.join(';')
end
alias :h! :history_do


# writes history to a named file.  This is useful if you want to show somebody
# something you did in irb, or for rapid prototyping.  Aliased to hw.
#
# Uses similar calling semantics to h!, that is, you can pass in fixnums,
# ranges, arrays, or any combination thereof.
def history_write( filename, *lines )
  File.open( filename, 'w' ) do |f|
    get_lines( lines ).each do |l|
      f.puts l
    end
  end
end
alias :hw :history_write


# copies history to the OS X clipboard, for pasting into something else.
# added by Andre Arko ([email protected]) on 26 November 2007
def history_copy( *lines )
  IO.popen('pbcopy', 'r+') do |clipboard|
    get_lines( lines ).each do |l|
      clipboard.puts l
    end
  end
end
alias :hc :history_copy


private

# simple getter to fetch from Readline
def get_line(line_number)
  Readline::HISTORY[line_number]
end


# the code what powers the line fetcherating.  Accepts an array and iterates
# over each entry, fetching that line from the history and placing it into a
# temporary array which is ultimately returned.
def get_lines( lines )
  out = []

  lines.each do |line|
    case line
    when Fixnum
      out << get_line( line )
    when Range
      line.to_a.each do |l|
        out << get_line( l )
      end
    end
  end

  return out
end


# prints out the contents of the line from history, along with a line number,
# if desired.
def print_line(line_number, show_line_numbers = true)
  print "[%04d] " % line_number if show_line_numbers
  puts get_line(line_number)
end