void local fn BooleanExercise
  BOOL areEqual    = (1 == 1)      // areEqual is YES
  BOOL areNotEqual = not areEqual  /* areNotEqual is converted to: areEqual = (-(1 == 1)). -1 throws a clang warning.
  NOTE: FB does not accept the "!" shorthand for "not", i.e. !areEqual, common in other languages. */

  print "areEqual    == "; areEqual
  print "areNotEqual == "; areNotEqual
  print

  // Boolean types assigned values outside YES or NO compile without complaint.
  boolean minusOneTest = -1
  print "minusOneTest == "; minusOneTest

  // Typical boolean value is use
  BOOL flatterRosettaReader = YES
  if (flatterRosettaReader)
    print
    print @"Rosetta Code programmers understand booleans."
    print
  end if

  // Defined Core Foundation boolean values
  print "kCFBooleanTrue  == "; kCFBooleanTrue
  print "kCFBooleanFalse == "; kCFBooleanFalse
  print

  // Number object assigned literal value
  CFNumberRef booleanObject = @(YES)
  print "booleanObject == "; booleanObject
  print

  // Number object created programmatically
  booleanObject = NO
  print "booleanObject variable reassigned as N0 == "; fn NumberWithBool( booleanObject )
  print
end fn

window 1

fn BooleanExercise

HandleEvents