class Parser::Source::Rewriter::Action

def initialize(range, replacement='')
  @range, @replacement = range, replacement
  freeze
end

def to_s
  if @range.length == 0 && @replacement.empty?
    'do nothing'
  elsif @range.length == 0
    "insert #{@replacement.inspect}"
  elsif @replacement.empty?
    "remove #{@range.length} character(s)"
  else
    "replace #{@range.length} character(s) with #{@replacement.inspect}"
  end
end