Struct Float64 

pub struct Float64 { /* private fields */ }

A float with optional original string representation for passthrough. 16 bytes: 8 for f64, 8 for Option<Box<str>> (NULL or heap pointer).

Fields are private. Construction goes through Float64::new or Float64::with_str, which enforce the no-NaN / no-Inf / no--0.0 invariants that the Hash and PartialEq impls on ExprValue depend on.

Implementations

impl Float64

pub fn new(v: f64) -> Result<Self, ExpressionError>

Create a new Float64, rejecting NaN and infinity, normalizing -0.0 to 0.0.

pub fn with_str(v: f64, s: String) -> Result<Self, ExpressionError>

Create a Float64 preserving the original string representation for lossless display.

pub fn value(&self) -> f64

The underlying f64 value.

pub fn to_display_string(&self) -> String

Display string: the original literal if preserved, otherwise formatted.

Methods from Deref<Target = f64>

pub const RADIX: u32 = 2

pub const BITS: u32 = 64

pub const MANTISSA_DIGITS: u32 = 53

pub const DIGITS: u32 = 15

pub const EPSILON: f64 = 2.2204460492503131e-16_f64

pub const MIN: f64 = -1.7976931348623157e+308_f64

pub const MIN_POSITIVE: f64 = 2.2250738585072014e-308_f64

pub const MAX: f64 = 1.7976931348623157e+308_f64

pub const MIN_EXP: i32 = -1021

pub const MAX_EXP: i32 = 1024

pub const MIN_10_EXP: i32 = -307

pub const MAX_10_EXP: i32 = 308

pub const NAN: f64

pub const INFINITY: f64

pub const NEG_INFINITY: f64

pub const MAX_EXACT_INTEGER: i64

pub const MIN_EXACT_INTEGER: i64

pub const SIGN_MASK: u64 = 0x8000_0000_0000_0000

pub const EXPONENT_MASK: u64 = 0x7ff0_0000_0000_0000

pub const MANTISSA_MASK: u64 = 0x000f_ffff_ffff_ffff

pub fn total_cmp(&self, other: &f64) -> Ordering

Returns the ordering between self and other.

Unlike the standard partial comparison between floating point numbers, this comparison always produces an ordering in accordance to the totalOrder predicate as defined in the IEEE 754 (2008 revision) floating point standard. The values are ordered in the following sequence:

• negative quiet NaN
• negative signaling NaN
• negative infinity
• negative numbers
• negative subnormal numbers
• negative zero
• positive zero
• positive subnormal numbers
• positive numbers
• positive infinity
• positive signaling NaN
• positive quiet NaN.

The ordering established by this function does not always agree with the PartialOrd and PartialEq implementations of f64. For example, they consider negative and positive zero equal, while total_cmp doesn’t.

The interpretation of the signaling NaN bit follows the definition in the IEEE 754 standard, which may not match the interpretation by some of the older, non-conformant (e.g. MIPS) hardware implementations.

Example

struct GoodBoy {
    name: String,
    weight: f64,
}

let mut bois = vec![
    GoodBoy { name: "Pucci".to_owned(), weight: 0.1 },
    GoodBoy { name: "Woofer".to_owned(), weight: 99.0 },
    GoodBoy { name: "Yapper".to_owned(), weight: 10.0 },
    GoodBoy { name: "Chonk".to_owned(), weight: f64::INFINITY },
    GoodBoy { name: "Abs. Unit".to_owned(), weight: f64::NAN },
    GoodBoy { name: "Floaty".to_owned(), weight: -5.0 },
];

bois.sort_by(|a, b| a.weight.total_cmp(&b.weight));

// `f64::NAN` could be positive or negative, which will affect the sort order.
if f64::NAN.is_sign_negative() {
    assert!(bois.into_iter().map(|b| b.weight)
        .zip([f64::NAN, -5.0, 0.1, 10.0, 99.0, f64::INFINITY].iter())
        .all(|(a, b)| a.to_bits() == b.to_bits()))
} else {
    assert!(bois.into_iter().map(|b| b.weight)
        .zip([-5.0, 0.1, 10.0, 99.0, f64::INFINITY, f64::NAN].iter())
        .all(|(a, b)| a.to_bits() == b.to_bits()))
}

Trait Implementations

impl Clone for Float64

fn clone(&self) -> Float64

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for Float64

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl Deref for Float64

type Target = f64

The resulting type after dereferencing.

fn deref(&self) -> &f64

Dereferences the value.

impl Display for Float64

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl Hash for Float64

fn hash<H: Hasher>(&self, state: &mut H)

Feeds this value into the given Hasher.

fn hash_slice<H>(data: &[Self], state: &mut H)

where H: Hasher, Self: Sized,

Feeds a slice of this type into the given Hasher.

impl PartialEq<f64> for Float64

fn eq(&self, other: &f64) -> bool

Tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &Rhs) -> bool

Tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.

impl PartialOrd<f64> for Float64

fn partial_cmp(&self, other: &f64) -> Option<Ordering>

This method returns an ordering between self and other values if one exists.

fn lt(&self, other: &Rhs) -> bool

Tests less than (for self and other) and is used by the < operator.

fn le(&self, other: &Rhs) -> bool

Tests less than or equal to (for self and other) and is used by the <= operator.

fn gt(&self, other: &Rhs) -> bool

Tests greater than (for self and other) and is used by the > operator.

fn ge(&self, other: &Rhs) -> bool

Tests greater than or equal to (for self and other) and is used by the >= operator.

impl Serialize for Float64

fn serialize<__S>(&self, __serializer: __S) -> Result<__S::Ok, __S::Error>

where __S: Serializer,

Serialize this value into the given Serde serializer.