anchor.diff:  final double SQRT2 = 1.4142135623730951;
   
   /**
  - * Parses a [String] representation of an [int], and returns an [int]. Throws a
  - * [FormatException] if [str] cannot be parsed as an [int].
  + * Parses a [String] representation of an [int], and returns an [int].
  + *
  + * Throws a [FormatException] if [str] cannot be parsed as an [int].
    */
   external int parseInt(String str);
   
   /**
    * Parses a [String] representation of a [double], and returns a [double].
  + *
    * Throws a [FormatException] if [str] cannot be parsed as a [double].
    */
   external double parseDouble(String str);
   
   /**
  -  * Returns the minimum of two numbers. If either argument is NaN returns NaN.
  -  * The minimum of [:-0.0:] and [:0.0:] is [:-0.0:]. If both arguments are
  -  * equal (int and doubles with the same mathematical value are equal) then
  -  * it is unspecified which of the two arguments is returned.
  +  * Returns the lesser of two numbers.
  +  *
  +  * Returns NaN if either argument is NaN.
  +  * The lesser of [:-0.0:] and [:0.0:] is [:-0.0:].
  +  * If the arguments are otherwise equal (including int and doubles with the
  +  * same mathematical value) then it is unspecified which of the two arguments
  +  * is returned.
     */
   num min(num a, num b) {
     if (a is num) {
  
positive.code: }
  
  /**
   * Returns the arc tangent of [a]/[b] with sign according to quadrant.
   */
  external double atan2(num a, num b);
  
  /**
   * If the [exponent] is an integer the result is of the same type as [x].
   * Otherwise it is a [double].
   */
  external num pow(num x, num exponent);
  
  // TODO(4512): Add documentation.
  external double sin(num x);
  external double cos(num x);
  external double tan(num x);
  external double acos(num x);
  external double asin(num x);
  external double atan(num x);
  external double sqrt(num x);
  external double exp(num x);
  external double log(num x);
  
negative.code: final double LN2 =  0.6931471805599453;
  
  /**
   * Base-2 logarithm of [E].
   */
  final double LOG2E = 1.4426950408889634;
  
  /**
   * Base-10 logarithm of [E].
   */
  final double LOG10E = 0.4342944819032518;
  
  