 
     @_displayOutput stack.peek()
 
+  _clearInput: ->
+    @input.clear()
+    @_displayInput()
+
   # Computes an unary operation using the given operator function.
   #
   # @param [Function] func  the given operator function

      .end()
      .find('.jscalc-sign')
        .toggleClass('active', negative)
    return

  # Enters the given digit.

  #
  _displayOutput: (value) ->
    negative = false
    unless @_isError value
      if value < 0
        negative = true
        value *= -1
      value = String(value)
    @_displayValue value, negative

  # Displays the given value with optional negative flag.
  #
