# File lib/yard/handlers/ruby/legacy/class_condition_handler.rb, line 28
  def parse_condition
    condition = nil

    # Right now we can handle very simple unary conditions like:
    #   if true
    #   if false
    #   if 0
    #   if 100 (not 0)
    #   if defined? SOME_CONSTANT
    #
    # The last case will do a lookup in the registry and then one
    # in the Ruby world (using eval).
    case statement.tokens[1..-1].to_s.strip
    when /^(\d+)$/
      condition = $1 != "0"
    when /^defined\?\s*\(?(.+?)\)?$/
      # defined? keyword used, let's see if we can look up the name
      # in the registry, then we'll try using Ruby's powers. eval() is not
      # *too* dangerous here since code is not actually executed.
      name = $1
      obj = YARD::Registry.resolve(namespace, name, true)
      begin
        condition = true if obj || Object.instance_eval("defined? #{name}")
      rescue SyntaxError, NameError
        condition = false
      end
    when "true"
      condition = true
    when "false"
      condition = false
    end

    if TkUNLESS === statement.tokens.first
      condition = !condition if condition != nil
    end
    condition
  end