/*
   Copyright 2023 Ondrej Lhotak. All rights reserved.

   Permission is granted for private study use by students registered in
   CS 241E in the Fall 2023 term.

   The contents of this file may not be published, in whole or in part,
   in print or electronic form.

   The contents of this file may be included in work submitted for CS
   241E assignments in Fall 2023. The contents of this file may not be
   submitted, in whole or in part, for credit in any other course.
*/
package cs241e.mips

/** An object containing utility methods for writing and pattern matching sequences of bits
  * using strings.
  */
object Bits {
  /** Constructs a bit sequence from a string.
    * Example: `Bits("01") == Seq(false, true)`
    */
  def apply(bits: String): Seq[Boolean] = bits.filter(bit => bit != ' ').map{
    case '0' => false
    case '1' => true
    case c => sys.error(s"illegal bit: $c")
  }

  /** Enables pattern matching of bit sequences using strings.
    * Example: {{{
    * (Seq(false, true) match {
    *   case Bits("01") => 42
    * }) == 42
    * }}}
    */
  def unapply(bits: Seq[Boolean]): Option[String] = Some(bits.map{if(_) '1' else '0'}.mkString)
}