class Byebug::History


Handles byebug’s history of commands.

def buffer


Array holding the list of commands in history
def buffer
  Readline::HISTORY.to_a
end

def clear


Discards history.
def clear
  size.times { pop }
end

def default_max_size


Never more than Setting[:histsize].

Max number of commands to be displayed when no size has been specified.
def default_max_size
  [Setting[:histsize], self.size].min
end

def ignore?(buf)


For now, empty lines and consecutive duplicates.

Whether a specific command should not be stored in history.
def ignore?(buf)
  return true if /^\s*$/.match?(buf)
  return false if Readline::HISTORY.empty?
  buffer[Readline::HISTORY.length - 1] == buf
end

def initialize 

def initialize
  self.size = 0
end

def last_ids(number)


Array of ids of the last +number+ commands.
def last_ids(number)
  (1 + size - number..size).to_a
end

def pop


Removes a command from Readline's history.
def pop
  self.size -= 1
  Readline::HISTORY.pop
end

def push(cmd)


Adds a new command to Readline's history.
def push(cmd)
  return if ignore?(cmd)
  self.size += 1
  Readline::HISTORY.push(cmd)
end

def restore


Restores history from disk.
def restore
  return unless File.exist?(Setting[:histfile])
  File.readlines(Setting[:histfile]).reverse_each { |l| push(l.chomp) }
end

def save


Saves history to disk.
def save
  n_cmds = Setting[:histsize] > size ? size : Setting[:histsize]
  File.open(Setting[:histfile], "w") do |file|
    n_cmds.times { file.puts(pop) }
  end
  clear
end

def specific_max_size(number)


The only bound here is not showing more items than available.

Max number of commands to be displayed when a size has been specified.
def specific_max_size(number)
  [self.size, number].min
end

def to_s(n_cmds)


Prints the requested numbers of history entries.
def to_s(n_cmds)
  show_size = n_cmds ? specific_max_size(n_cmds) : default_max_size
  commands = buffer.last(show_size)
  last_ids(show_size).zip(commands).map do |l|
    format("%<position>5d  %<command>s", position: l[0], command: l[1])
  end.join("\n") + "\n"
end