class Byebug::DisplayCommand

def self.always_run
  2
end

def description
  <<-EOD
    disp[lay][ <expression>]
    If <expression> specified, adds <expression> into display expression
    list. Otherwise, it lists all expressions.
  EOD
end

def display_expression(exp)
  print pr('display.result',
           n: @state.display.size,
           exp: exp,
           result: bb_warning_eval(exp).inspect)
end

def execute
  return print_display_expressions unless @match && @match[1]
  @state.display.push [true, @match[1]]
  display_expression(@match[1])
end

def print_display_expressions
  result = prc('display.result', @state.display) do |item, index|
    is_active, expression = item
    if is_active
      { n: index + 1,
        exp: expression,
        result: bb_warning_eval(expression).inspect }
    end
  end
  print result
end

def regexp
  /^\s* disp(?:lay)? (?:\s+ (.+))? \s*$/x
end