// P47 (*) Truth tables for logical expressions (2).
//     Continue problem P46 by redefining and, or, etc as operators.  (i.e. make
//     them methods of a new class with an implicit conversion from Boolean.)
//     not will have to be left as a object method.
//
//     scala> table2((a: Boolean, b: Boolean) => a and (a or not(b)))
//     A     B     result
//     true  true  true
//     true  false true
//     false true  false
//     false false false

// For simplicity, we remove `and`, `or`, `equ`, `xor`, `nor`, `nand`, and
// `impl` from the S99Logic object before putting them into a new class.

class S99Logic(a: Boolean) {
  import S99Logic._
  
  def and(b: Boolean): Boolean = (a, b) match {
    case (true, true) => true
    case _            => false
  }
  def or(b: Boolean): Boolean = (a, b) match {
    case (true, _) => true
    case (_, true) => true
    case _         => false
  }
  def equ(b: Boolean): Boolean = (a and b) or (not(a) and not(b))
  def xor(b: Boolean): Boolean = not(a equ b)
  def nor(b: Boolean): Boolean = not(a or b)
  def nand(b: Boolean): Boolean = not(a and b)
  def impl(b: Boolean): Boolean = not(a) or b
}

object S99Logic {
  implicit def boolean2S99Logic(a: Boolean): S99Logic = new S99Logic(a)
}