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1 // Copyright (c) 2012, the Dart project authors. Please see the AUTHORS file | 1 // Copyright (c) 2012, the Dart project authors. Please see the AUTHORS file |
2 // for details. All rights reserved. Use of this source code is governed by a | 2 // for details. All rights reserved. Use of this source code is governed by a |
3 // BSD-style license that can be found in the LICENSE file. | 3 // BSD-style license that can be found in the LICENSE file. |
4 | 4 |
5 part of dart.core; | 5 part of dart.core; |
6 | 6 |
7 /** | 7 /** |
8 * An integer or floating-point number. | 8 * An integer or floating-point number. |
9 * | 9 * |
10 * It is a compile-time error for any type other than [int] or [double] | 10 * It is a compile-time error for any type other than [int] or [double] |
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59 * Compares this to `other`. | 59 * Compares this to `other`. |
60 * | 60 * |
61 * Returns a negative number if `this` is less than `other`, zero if they are | 61 * Returns a negative number if `this` is less than `other`, zero if they are |
62 * equal, and a positive number if `this` is greater than `other`. | 62 * equal, and a positive number if `this` is greater than `other`. |
63 * | 63 * |
64 * The orderding represented by this method is a total ordering of [num] | 64 * The orderding represented by this method is a total ordering of [num] |
65 * values. All distinct doubles are non-equal, as are all distinct integers, | 65 * values. All distinct doubles are non-equal, as are all distinct integers, |
66 * but integers are equal to doubles if they have the same numerical | 66 * but integers are equal to doubles if they have the same numerical |
67 * value. | 67 * value. |
68 * | 68 * |
69 * For ordering, the double NaN value is considered equal to itself, and | 69 * For doubles, the `compareTo` operation is different from the partial |
70 * greater than any numeric value (unlike its behavior in `operator==`). | 70 * ordering given by [operator==], [operator<] and [operator>]. For example, |
| 71 * IEEE doubles impose that `0.0 == -0.0` and all comparison operations on |
| 72 * NaN return false. |
71 * | 73 * |
72 * The double value -0.0 is considered less than 0.0 (and the integer 0), but | 74 * This function imposes a complete ordering for doubles. When using |
73 * greater than any non-zero negative value. | 75 * `compareTo` the following properties hold: |
74 * | 76 * |
75 * Positive infinity is greater than any finite value (any value apart from | 77 * - All NaN values are considered equal, and greater than any numeric value. |
76 * itself and NaN), and negative infinity is less than any other value. | 78 * - -0.0 is less than 0.0 (and the integer 0), but greater than any non-zero |
| 79 * negative value. |
| 80 * - Negative infinity is less than all other values and positive infinity is |
| 81 * greater than all non-NaN values. |
| 82 * - All other values are compared using their numeric value. |
77 * | 83 * |
78 * All other values are compared using their numeric value. | 84 * Examples: |
| 85 * ``` |
| 86 * print(1.compareTo(2)); // => -1 |
| 87 * print(2.compareTo(1)); // => 1 |
| 88 * print(1.compareTo(1)); // => 0 |
| 89 * |
| 90 * // The following comparisons yield different results than the |
| 91 * // corresponding comparison operators. |
| 92 * print((-0.0).compareTo(0.0)); // => -1 |
| 93 * print(double.NAN.compareTo(double.NAN)); // => 0 |
| 94 * print(double.INFINITY.compareTo(double.NAN)); // => -1 |
| 95 * |
| 96 * // -0.0, and NaN comparison operators have rules imposed by the IEEE |
| 97 * // standard. |
| 98 * print(-0.0 == 0.0); // => true |
| 99 * print(double.NAN == double.NAN); // => false |
| 100 * print(double.INFINITY < double.NAN); // => false |
| 101 * print(double.NAN < double.INFINITY); // => false |
| 102 * print(double.NAN == double.INFINITY); // => false |
79 */ | 103 */ |
80 int compareTo(num other); | 104 int compareTo(num other); |
81 | 105 |
82 /** Addition operator. */ | 106 /** Addition operator. */ |
83 num operator +(num other); | 107 num operator +(num other); |
84 | 108 |
85 /** Subtraction operator. */ | 109 /** Subtraction operator. */ |
86 num operator -(num other); | 110 num operator -(num other); |
87 | 111 |
88 /** Multiplication operator. */ | 112 /** Multiplication operator. */ |
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447 result = double.parse(source, _returnDoubleNull); | 471 result = double.parse(source, _returnDoubleNull); |
448 if (result != null) return result; | 472 if (result != null) return result; |
449 if (onError == null) throw new FormatException(input); | 473 if (onError == null) throw new FormatException(input); |
450 return onError(input); | 474 return onError(input); |
451 } | 475 } |
452 | 476 |
453 /** Helper functions for [parse]. */ | 477 /** Helper functions for [parse]. */ |
454 static int _returnIntNull(String _) => null; | 478 static int _returnIntNull(String _) => null; |
455 static double _returnDoubleNull(String _) => null; | 479 static double _returnDoubleNull(String _) => null; |
456 } | 480 } |
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