anchor.diff:  
     /// Tests REAL evaluation of default functions.
     void defFuncRealEval() {
  -    Number zero, one, infinity, negInfty, e, pi;
  +    Number zero, one, two, infinity, negInfty, e, pi;
       zero = Number(0);
       one = Number(1);
  +    two = Number(2);
       infinity = Number(double.infinity);
       negInfty = Number(double.negativeInfinity);
       pi = Number(math.pi);
  
positive.code:     expect(eval, closeTo(0.841, 0.001));
      // sin(PI) -> 0
      eval = Sin(pi).evaluate(real, cm);
      expect(eval, closeTo(0, 0.00001));
      // sin(-PI) -> 0
      eval = Sin(-pi).evaluate(real, cm);
      expect(eval, closeTo(0, 0.00001));
      // sin(INFTY) -> [-1,1] / NaN
      eval = Sin(infinity).evaluate(real, cm);
      expect(eval, isNot(equals(eval))); // NaN
  
negative.code:     // cos(-PI) -> -1
      eval = Cos(-pi).evaluate(real, cm);
      expect(eval, equals(-1));
      // cos(PI/2) -> 0
      eval = Cos(pi/two).evaluate(real, cm);
      expect(eval, equals(0));
      // cos(INFTY) -> [-1,1] / NaN
      eval = Cos(infinity).evaluate(real, cm);
      expect(eval, isNot(equals(eval))); // NaN
  