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// Copyright (c) 2012, the Dart project authors. Please see the AUTHORS file
// for details. All rights reserved. Use of this source code is governed by a
// BSD-style license that can be found in the LICENSE file.
part of dart.core;
/// An integer or floating-point number.
///
/// It is a compile-time error for any type other than [int] or [double]
/// to attempt to extend or implement `num`.
abstract class num implements Comparable<num> {
/// Test whether this value is numerically equal to `other`.
///
/// If both operands are [double]s, they are equal if they have the same
/// representation, except that:
///
/// * zero and minus zero (0.0 and -0.0) are considered equal. They
/// both have the numerical value zero.
/// * NaN is not equal to anything, including NaN. If either operand is
/// NaN, the result is always false.
///
/// If one operand is a [double] and the other is an [int], they are equal if
/// the double has an integer value (finite with no fractional part) and
/// the numbers have the same numerical value.
///
/// If both operands are integers, they are equal if they have the same value.
///
/// Returns false if [other] is not a [num].
///
/// Notice that the behavior for NaN is non-reflexive. This means that
/// equality of double values is not a proper equality relation, as is
/// otherwise required of `operator==`. Using NaN in, e.g., a [HashSet]
/// will fail to work. The behavior is the standard IEEE-754 equality of
/// doubles.
///
/// If you can avoid NaN values, the remaining doubles do have a proper
/// equality relation, and can be used safely.
///
/// Use [compareTo] for a comparison that distinguishes zero and minus zero,
/// and that considers NaN values as equal.
bool operator ==(Object other);
/// Returns a hash code for a numerical value.
///
/// The hash code is compatible with equality. It returns the same value
/// for an [int] and a [double] with the same numerical value, and therefore
/// the same value for the doubles zero and minus zero.
///
/// No guarantees are made about the hash code of NaN values.
int get hashCode;
/// Compares this to `other`.
///
/// Returns a negative number if `this` is less than `other`, zero if they are
/// equal, and a positive number if `this` is greater than `other`.
///
/// The ordering represented by this method is a total ordering of [num]
/// values. All distinct doubles are non-equal, as are all distinct integers,
/// but integers are equal to doubles if they have the same numerical
/// value.
///
/// For doubles, the `compareTo` operation is different from the partial
/// ordering given by [operator==], [operator<] and [operator>]. For example,
/// IEEE doubles impose that `0.0 == -0.0` and all comparison operations on
/// NaN return false.
///
/// This function imposes a complete ordering for doubles. When using
/// `compareTo` the following properties hold:
///
/// - All NaN values are considered equal, and greater than any numeric value.
/// - -0.0 is less than 0.0 (and the integer 0), but greater than any non-zero
/// negative value.
/// - Negative infinity is less than all other values and positive infinity is
/// greater than all non-NaN values.
/// - All other values are compared using their numeric value.
///
/// Examples:
/// ```
/// print(1.compareTo(2)); // => -1
/// print(2.compareTo(1)); // => 1
/// print(1.compareTo(1)); // => 0
///
/// // The following comparisons yield different results than the
/// // corresponding comparison operators.
/// print((-0.0).compareTo(0.0)); // => -1
/// print(double.nan.compareTo(double.nan)); // => 0
/// print(double.infinity.compareTo(double.nan)); // => -1
///
/// // -0.0, and NaN comparison operators have rules imposed by the IEEE
/// // standard.
/// print(-0.0 == 0.0); // => true
/// print(double.nan == double.nan); // => false
/// print(double.infinity < double.nan); // => false
/// print(double.nan < double.infinity); // => false
/// print(double.nan == double.infinity); // => false
/// ```
int compareTo(num other);
/// Adds [other] to this number.
///
/// The result is an [int], as described by [int.+],
/// if both this number and [other] is an integer,
/// otherwise the result is a [double].
num operator +(num other);
/// Subtracts [other] from this number.
///
/// The result is an [int], as described by [int.-],
/// if both this number and [other] is an integer,
/// otherwise the result is a [double].
num operator -(num other);
/// Multiplies this number by [other].
///
/// The result is an [int], as described by [int.*],
/// if both this number and [other] is an integer,
/// otherwise the result is a [double].
num operator *(num other);
/// Euclidean modulo of this number by [other].
///
/// Returns the remainder of the Euclidean division.
/// The Euclidean division of two integers `a` and `b`
/// yields two integers `q` and `r` such that
/// `a == b * q + r` and `0 <= r < b.abs()`.
///
/// The Euclidean division is only defined for integers, but can be easily
/// extended to work with doubles. In that case `q` is stil an integer,
/// but `r` may have a non-integer value that still satisfies `0 <= r < |b|`.
///
/// The sign of the returned value `r` is always positive.
///
/// See [remainder] for the remainder of the truncating division.
///
/// The result is an [int], as described by [int.%],
/// if both this number and [other] is an integer,
/// otherwise the result is a [double].
num operator %(num other);
/// Divides this number by [other].
double operator /(num other);
/// Truncating division operator.
///
/// If either operand is a [double] then the result of the truncating division
/// `a ~/ b` is equivalent to `(a / b).truncate().toInt()`.
///
/// If both operands are [int]s then `a ~/ b` performs the truncating
/// integer division.
int operator ~/(num other);
/// The negation of this value.
///
/// The negation of a number is a number of the same kind
/// (`int` or `double`) representing the negation of the
/// numbers numerical value (the result of subtracting the
/// number from zero), if that value *exists*.
///
/// Negating a double gives a number with same magnitude
/// as the original value (`number.abs() == (-number).abs()`),
/// and the opposite sign (`-(number.sign) == (-number).sign`).
///
/// Negating an integer, `-number`, is equivalent to subtracting
/// it from zero, `0 - number`.
///
/// (Both properties generally also hold for the other type,
/// but with a few edge case exceptions).
num operator -();
/// The remainder of the truncating division of `this` by [other].
///
/// The result `r` of this operation satisfies:
/// `this == (this ~/ other) * other + r`.
/// As a consequence the remainder `r` has the same sign as the divider `this`.
///
/// The result is an [int], as described by [int.remainder],
/// if both this number and [other] is an integer,
/// otherwise the result is a [double].
num remainder(num other);
/// Whether [other] is numerically smaller than this number.
///
/// If either operand is the [double] NaN, the result is always false.
bool operator <(num other);
/// Whether [other] is numerically smaller than or equal to this number.
///
/// If either operand is the [double] NaN, the result is always false.
bool operator <=(num other);
/// Whether [other] is numerically greater than this number.
///
/// If either operand is the [double] NaN, the result is always false.
bool operator >(num other);
/// Whether [other] is numerically greater than or equal to this number.
///
/// If either operand is the [double] NaN, the result is always false.
bool operator >=(num other);
/// Whether the number is the double Not-a-Number value.
bool get isNaN;
/// Whether if the number is negative.
///
/// Negative numbers are those less than zero, and the double `-0.0`.
bool get isNegative;
/// Whether the number is positive infinity or negative infinity.
bool get isInfinite;
/// Whether the number is finite.
///
/// The only non-finite numbers are NaN, positive infinity, and
/// negative infinity. All integers are finite.
bool get isFinite;
/// The absolute value of this number.
///
/// The absolute value is the value itself, if the value is non-negative,
/// and `-value` if the value is negative.
num abs();
/// Negative one, zero or positive one depending on the sign and
/// numerical value of the number.
///
/// Returns minus one if the number is less than zero,
/// plus one if the number is greater than zero,
/// and zero if the number is equal to zero.
///
/// Returns NaN if the number is the [double] NaN value.
///
/// Returns a number of the same type as this number.
/// For doubles, `-0.0.sign == -0.0`.
///
/// The result satisfies:
/// ```dart
/// n == n.sign * n.abs()
/// ```
/// for all numbers `n` (except NaN, because NaN isn't `==` to itself).
num get sign;
/// The integer closest to this number.
///
/// Rounds away from zero when there is no closest integer:
/// `(3.5).round() == 4` and `(-3.5).round() == -4`.
///
/// The number must be finite (see [isFinite]).
///
/// If the value is greater than the highest representable positive integer,
/// the result is that highest positive integer.
/// If the value is smaller than the highest representable negative integer,
/// the result is that highest negative integer.
int round();
/// The greatest integer no greater than this number.
///
/// Rounds fractional values towards negative infinity.
///
/// The number must be finite (see [isFinite]).
///
/// If the value is greater than the highest representable positive integer,
/// the result is that highest positive integer.
/// If the value is smaller than the highest representable negative integer,
/// the result is that highest negative integer.
int floor();
/// The least integer no smaller than `this`.
///
/// Rounds fractional values towards positive infinitiy.
///
/// The number must be finite (see [isFinite]).
///
/// If the value is greater than the highest representable positive integer,
/// the result is that highest positive integer.
/// If the value is smaller than the highest representable negative integer,
/// the result is that highest negative integer.
int ceil();
/// The integer obtained by discarding any fractional digits from `this`.
///
/// Rounds fractional values towards zero.
///
/// The number must be finite (see [isFinite]).
///
/// If the value is greater than the highest representable positive integer,
/// the result is that highest positive integer.
/// If the value is smaller than the highest representable negative integer,
/// the result is that highest negative integer.
int truncate();
/// The double integer value closest to this value.
///
/// Rounds away from zero when there is no closest integer:
/// `(3.5).roundToDouble() == 4` and `(-3.5).roundToDouble() == -4`.
///
/// If this is already an integer valued double, including `-0.0`, or it is a
/// non-finite double value, the value is returned unmodified.
///
/// For the purpose of rounding, `-0.0` is considered to be below `0.0`,
/// and `-0.0` is therefore considered closer to negative numbers than `0.0`.
/// This means that for a value, `d` in the range `-0.5 < d < 0.0`,
/// the result is `-0.0`.
double roundToDouble();
/// Returns the greatest double integer value no greater than `this`.
///
/// If this is already an integer valued double, including `-0.0`, or it is a
/// non-finite double value, the value is returned unmodified.
///
/// For the purpose of rounding, `-0.0` is considered to be below `0.0`.
/// A number `d` in the range `0.0 < d < 1.0` will return `0.0`.
double floorToDouble();
/// Returns the least double integer value no smaller than `this`.
///
/// If this is already an integer valued double, including `-0.0`, or it is a
/// non-finite double value, the value is returned unmodified.
///
/// For the purpose of rounding, `-0.0` is considered to be below `0.0`.
/// A number `d` in the range `-1.0 < d < 0.0` will return `-0.0`.
double ceilToDouble();
/// Returns the double integer value obtained by discarding any fractional
/// digits from the double value of `this`.
///
/// If this is already an integer valued double, including `-0.0`, or it is a
/// non-finite double value, the value is returned unmodified.
///
/// For the purpose of rounding, `-0.0` is considered to be below `0.0`.
/// A number `d` in the range `-1.0 < d < 0.0` will return `-0.0`, and
/// in the range `0.0 < d < 1.0` it will return 0.0.
double truncateToDouble();
/// Returns this [num] clamped to be in the range [lowerLimit]-[upperLimit].
///
/// The comparison is done using [compareTo] and therefore takes `-0.0` into
/// account. This also implies that [double.nan] is treated as the maximal
/// double value.
///
/// The arguments [lowerLimit] and [upperLimit] must form a valid range where
/// `lowerLimit.compareTo(upperLimit) <= 0`.
num clamp(num lowerLimit, num upperLimit);
/// Truncates this [num] to an integer and returns the result as an [int].
///
/// Equivalent to [truncate].
int toInt();
/// This number as a [double].
///
/// If an integer number is not precisely representable as a [double],
/// an approximation is returned.
double toDouble();
/// A decimal-point string-representation of this number.
///
/// Converts this number to a [double]
/// before computing the string representation,
/// as by [toDouble].
///
/// If the absolute value of `this` is greater then or equal to `10^21` then
/// this methods returns an exponential representation computed by
/// `this.toStringAsExponential()`. Otherwise the result
/// is the closest string representation with exactly [fractionDigits] digits
/// after the decimal point. If [fractionDigits] equals 0 then the decimal
/// point is omitted.
///
/// The parameter [fractionDigits] must be an integer satisfying:
/// `0 <= fractionDigits <= 20`.
///
/// Examples:
/// ```dart
/// 1.toStringAsFixed(3); // 1.000
/// (4321.12345678).toStringAsFixed(3); // 4321.123
/// (4321.12345678).toStringAsFixed(5); // 4321.12346
/// 123456789012345.toStringAsFixed(3); // 123456789012345.000
/// 10000000000000000.toStringAsFixed(4); // 10000000000000000.0000
/// 5.25.toStringAsFixed(0); // 5
/// ```
String toStringAsFixed(int fractionDigits);
/// An exponential string-representation of this number.
///
/// Converts this number to a [double]
/// before computing the string representation.
///
/// If [fractionDigits] is given then it must be an integer satisfying:
/// `0 <= fractionDigits <= 20`. In this case the string contains exactly
/// [fractionDigits] after the decimal point. Otherwise, without the parameter,
/// the returned string uses the shortest number of digits that accurately
/// represent this number.
///
/// If [fractionDigits] equals 0 then the decimal point is omitted.
/// Examples:
/// ```dart
/// 1.toStringAsExponential(); // 1e+0
/// 1.toStringAsExponential(3); // 1.000e+0
/// 123456.toStringAsExponential(); // 1.23456e+5
/// 123456.toStringAsExponential(3); // 1.235e+5
/// 123.toStringAsExponential(0); // 1e+2
/// ```
String toStringAsExponential([int? fractionDigits]);
/// A string representation with [precision] significant digits.
///
/// Converts this number to a [double]
/// and returns a string representation of that value
/// with exactly [precision] significant digits.
///
/// The parameter [precision] must be an integer satisfying:
/// `1 <= precision <= 21`.
///
/// Examples:
/// ```dart
/// 1.toStringAsPrecision(2); // 1.0
/// 1e15.toStringAsPrecision(3); // 1.00e+15
/// 1234567.toStringAsPrecision(3); // 1.23e+6
/// 1234567.toStringAsPrecision(9); // 1234567.00
/// 12345678901234567890.toStringAsPrecision(20); // 12345678901234567168
/// 12345678901234567890.toStringAsPrecision(14); // 1.2345678901235e+19
/// 0.00000012345.toStringAsPrecision(15); // 1.23450000000000e-7
/// 0.0000012345.toStringAsPrecision(15); // 0.00000123450000000000
/// ```
String toStringAsPrecision(int precision);
/// The shortest string that correctly represent this number number.
///
/// All [double]s in the range `10^-6` (inclusive) to `10^21` (exclusive)
/// are converted to their decimal representation with at least one digit
/// after the decimal point. For all other doubles,
/// except for special values like `NaN` or `Infinity`, this method returns an
/// exponential representation (see [toStringAsExponential]).
///
/// Returns `"NaN"` for [double.nan], `"Infinity"` for [double.infinity], and
/// `"-Infinity"` for [double.negativeInfinity].
///
/// An [int] is converted to a decimal representation with no decimal point.
///
/// Examples:
/// ```dart
/// (0.000001).toString(); // "0.000001"
/// (0.0000001).toString(); // "1e-7"
/// (111111111111111111111.0).toString(); // "111111111111111110000.0"
/// (100000000000000000000.0).toString(); // "100000000000000000000.0"
/// (1000000000000000000000.0).toString(); // "1e+21"
/// (1111111111111111111111.0).toString(); // "1.1111111111111111e+21"
/// 1.toString(); // "1"
/// 111111111111111111111.toString(); // "111111111111111110000"
/// 100000000000000000000.toString(); // "100000000000000000000"
/// 1000000000000000000000.toString(); // "1000000000000000000000"
/// 1111111111111111111111.toString(); // "1111111111111111111111"
/// 1.234e5.toString(); // 123400
/// 1234.5e6.toString(); // 1234500000
/// 12.345e67.toString(); // 1.2345e+68
/// ```
/// Note: the conversion may round the output if the returned string
/// is accurate enough to uniquely identify the input-number.
/// For example the most precise representation of the [double] `9e59` equals
/// `"899999999999999918767229449717619953810131273674690656206848"`, but
/// this method returns the shorter (but still uniquely identifying) `"9e59"`.
String toString();
/// Parses a string containing a number literal into a number.
///
/// The method first tries to read the [input] as integer (similar to
/// [int.parse] without a radix).
/// If that fails, it tries to parse the [input] as a double (similar to
/// [double.parse]).
/// If that fails, too, it invokes [onError] with [input], and the result
/// of that invocation becomes the result of calling `parse`.
///
/// If no [onError] is supplied, it defaults to a function that throws a
/// [FormatException].
///
/// For any number `n`, this function satisfies
/// `identical(n, num.parse(n.toString()))` (except when `n` is a NaN `double`
/// with a payload).
///
/// The [onError] parameter is deprecated and will be removed.
/// Instead of `num.parse(string, (string) { ... })`,
/// you should use `num.tryParse(string) ?? (...)`.
static num parse(String input, [@deprecated num onError(String input)?]) {
num? result = tryParse(input);
if (result != null) return result;
if (onError == null) throw FormatException(input);
return onError(input);
}
/// Parses a string containing a number literal into a number.
///
/// Like [parse] except that this function returns `null` for invalid inputs
/// instead of throwing.
static num? tryParse(String input) {
String source = input.trim();
// TODO(lrn): Optimize to detect format and result type in one check.
return int.tryParse(source) ?? double.tryParse(source);
}
}