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