P46.scala

package logic

// P46 (**) Truth tables for logical expressions.
//     Define functions and, or, nand, nor, xor, impl, and equ (for logical
//     equivalence) which return true or false according to the result of their
//     respective operations; e.g. and(A, B) is true if and only if both A and B
//     are true.
//
//     scala> and(true, true)
//     res0: Boolean = true
//
//     scala> xor(true. true)
//     res1: Boolean = false
//
//     A logical expression in two variables can then be written as a function of
//     two variables, e.g: (a: Boolean, b: Boolean) => and(or(a, b), nand(a, b))
//
//     Now, write a function called table2 which prints the truth table of a
//     given logical expression in two variables.
//
//     scala> table2((a: Boolean, b: Boolean) => and(a, or(a, b)))
//     A     B     result
//     true  true  true
//     true  false true
//     false true  false
//     false false false

object P46:
  def not(x: Boolean): Boolean =
    x == false

  def table2(f: (x: Boolean, y: Boolean) => Boolean): List[(Boolean, Boolean, Boolean)] =
    for
      a <- List(true, false)
      b <- List(true, false)
    yield (a, b, f(a, b))