Struct Decimal 

pub struct Decimal(/* private fields */);

A wrapper around rust_decimal::Decimal which serializes to and from f64.

We have a specific need for f64 as underlying type when serialized into JSON, since we bridge to Typst dictionary and we must be able to perform arithmetic with values as numbers in Typst - which we cannot do with Strings.

We don’t need the full precision of rust_decimal::Decimal in this context, so we use f64 for serialization and deserialization, which allows us to easily bridge to Typst.

Implementations

impl Decimal

pub const ZERO: Decimal

pub const ONE: Decimal

pub const TWO: Decimal

pub const EIGHT: Decimal

Methods from Deref<Target = Decimal>

pub const MIN: Decimal = MIN

pub const MAX: Decimal = MAX

pub const ZERO: Decimal = ZERO

pub const ONE: Decimal = ONE

pub const NEGATIVE_ONE: Decimal = NEGATIVE_ONE

pub const TWO: Decimal = TWO

pub const TEN: Decimal = TEN

pub const ONE_HUNDRED: Decimal = ONE_HUNDRED

pub const ONE_THOUSAND: Decimal = ONE_THOUSAND

pub const MAX_SCALE: u32 = MAX_SCALE_U32

pub const PI: Decimal

pub const HALF_PI: Decimal

pub const QUARTER_PI: Decimal

pub const TWO_PI: Decimal

pub const E: Decimal

pub const E_INVERSE: Decimal

pub fn scale(&self) -> u32

Returns the scale of the decimal number, otherwise known as e.

Example

let num = Decimal::new(1234, 3);
assert_eq!(num.scale(), 3u32);

pub fn mantissa(&self) -> i128

Returns the mantissa of the decimal number.

Example

let num = dec!(-1.2345678);
assert_eq!(num.mantissa(), -12345678i128);
assert_eq!(num.scale(), 7);

pub fn is_zero(&self) -> bool

Returns true if this Decimal number is equivalent to zero.

Example

let num = Decimal::ZERO;
assert!(num.is_zero());

pub fn is_integer(&self) -> bool

Returns true if this Decimal number has zero fractional part (is equal to an integer)

Example

assert_eq!(dec!(5).is_integer(), true);
// Trailing zeros are also ignored
assert_eq!(dec!(5.0000).is_integer(), true);
// If there is a fractional part then it is not an integer
assert_eq!(dec!(5.1).is_integer(), false);

pub fn serialize(&self) -> [u8; 16]

Returns a serialized version of the decimal number. The resulting byte array will have the following representation:

• Bytes 1-4: flags
• Bytes 5-8: lo portion of m
• Bytes 9-12: mid portion of m
• Bytes 13-16: high portion of m

pub fn is_negative(&self) -> bool

👎Deprecated since 0.6.3:

please use is_sign_negative instead

Returns true if the decimal is negative.

pub fn is_positive(&self) -> bool

👎Deprecated since 0.6.3:

please use is_sign_positive instead

Returns true if the decimal is positive.

pub fn is_sign_negative(&self) -> bool

Returns true if the sign bit of the decimal is negative.

Example

assert_eq!(true, Decimal::new(-1, 0).is_sign_negative());
assert_eq!(false, Decimal::new(1, 0).is_sign_negative());

pub fn is_sign_positive(&self) -> bool

Returns true if the sign bit of the decimal is positive.

Example

assert_eq!(false, Decimal::new(-1, 0).is_sign_positive());
assert_eq!(true, Decimal::new(1, 0).is_sign_positive());

pub fn trunc(&self) -> Decimal

Returns a new Decimal integral with no fractional portion. This is a true truncation whereby no rounding is performed.

Example

let pi = dec!(3.141);
assert_eq!(pi.trunc(), dec!(3));

// Negative numbers are similarly truncated without rounding
let neg = dec!(-1.98765);
assert_eq!(neg.trunc(), Decimal::NEGATIVE_ONE);

pub fn trunc_with_scale(&self, scale: u32) -> Decimal

Returns a new Decimal with the fractional portion delimited by scale. This is a true truncation whereby no rounding is performed.

Example

let pi = dec!(3.141592);
assert_eq!(pi.trunc_with_scale(2), dec!(3.14));

// Negative numbers are similarly truncated without rounding
let neg = dec!(-1.98765);
assert_eq!(neg.trunc_with_scale(1), dec!(-1.9));

pub fn fract(&self) -> Decimal

Returns a new Decimal representing the fractional portion of the number.

Example

let pi = Decimal::new(3141, 3);
let fract = Decimal::new(141, 3);
// note that it returns a decimal
assert_eq!(pi.fract(), fract);

pub fn abs(&self) -> Decimal

Computes the absolute value of self.

Example

let num = Decimal::new(-3141, 3);
assert_eq!(num.abs().to_string(), "3.141");

pub fn floor(&self) -> Decimal

Returns the largest integer less than or equal to a number.

Example

let num = Decimal::new(3641, 3);
assert_eq!(num.floor().to_string(), "3");

pub fn ceil(&self) -> Decimal

Returns the smallest integer greater than or equal to a number.

Example

let num = Decimal::new(3141, 3);
assert_eq!(num.ceil().to_string(), "4");
let num = Decimal::new(3, 0);
assert_eq!(num.ceil().to_string(), "3");

pub fn normalize(&self) -> Decimal

Strips any trailing zero’s from a Decimal and converts -0 to 0.

Example

let number = Decimal::from_str("3.100")?;
assert_eq!(number.normalize().to_string(), "3.1");

pub fn round(&self) -> Decimal

Returns a new Decimal number with no fractional portion (i.e. an integer). Rounding currently follows “Bankers Rounding” rules. e.g. 6.5 -> 6, 7.5 -> 8

Example

// Demonstrating bankers rounding...
let number_down = Decimal::new(65, 1);
let number_up   = Decimal::new(75, 1);
assert_eq!(number_down.round().to_string(), "6");
assert_eq!(number_up.round().to_string(), "8");

pub fn round_dp_with_strategy( &self, dp: u32, strategy: RoundingStrategy, ) -> Decimal

Returns a new Decimal number with the specified number of decimal points for fractional portion. Rounding is performed using the provided RoundingStrategy

Arguments

• dp: the number of decimal points to round to.
• strategy: the RoundingStrategy to use.

Example

let tax = dec!(3.4395);
assert_eq!(tax.round_dp_with_strategy(2, RoundingStrategy::MidpointAwayFromZero).to_string(), "3.44");

pub fn round_dp(&self, dp: u32) -> Decimal

Returns a new Decimal number with the specified number of decimal points for fractional portion. Rounding currently follows “Bankers Rounding” rules. e.g. 6.5 -> 6, 7.5 -> 8

Arguments

• dp: the number of decimal points to round to.

Example

let pi = dec!(3.1415926535897932384626433832);
assert_eq!(pi.round_dp(2).to_string(), "3.14");

pub fn round_sf(&self, digits: u32) -> Option<Decimal>

Returns Some(Decimal) number rounded to the specified number of significant digits. If the resulting number is unable to be represented by the Decimal number then None will be returned. When the number of significant figures of the Decimal being rounded is greater than the requested number of significant digits then rounding will be performed using MidpointNearestEven strategy.

Arguments

• digits: the number of significant digits to round to.

Remarks

A significant figure is determined using the following rules:

1. Non-zero digits are always significant.
2. Zeros between non-zero digits are always significant.
3. Leading zeros are never significant.
4. Trailing zeros are only significant if the number contains a decimal point.

Example

let value = dec!(305.459);
assert_eq!(value.round_sf(0), Some(dec!(0)));
assert_eq!(value.round_sf(1), Some(dec!(300)));
assert_eq!(value.round_sf(2), Some(dec!(310)));
assert_eq!(value.round_sf(3), Some(dec!(305)));
assert_eq!(value.round_sf(4), Some(dec!(305.5)));
assert_eq!(value.round_sf(5), Some(dec!(305.46)));
assert_eq!(value.round_sf(6), Some(dec!(305.459)));
assert_eq!(value.round_sf(7), Some(dec!(305.4590)));
assert_eq!(Decimal::MAX.round_sf(1), None);

let value = dec!(0.012301);
assert_eq!(value.round_sf(3), Some(dec!(0.0123)));

pub fn round_sf_with_strategy( &self, digits: u32, strategy: RoundingStrategy, ) -> Option<Decimal>

Returns Some(Decimal) number rounded to the specified number of significant digits. If the resulting number is unable to be represented by the Decimal number then None will be returned. When the number of significant figures of the Decimal being rounded is greater than the requested number of significant digits then rounding will be performed using the provided RoundingStrategy.

Arguments

• digits: the number of significant digits to round to.
• strategy: if required, the rounding strategy to use.

Remarks

A significant figure is determined using the following rules:

1. Non-zero digits are always significant.
2. Zeros between non-zero digits are always significant.
3. Leading zeros are never significant.
4. Trailing zeros are only significant if the number contains a decimal point.

Example

let value = dec!(305.459);
assert_eq!(value.round_sf_with_strategy(0, RoundingStrategy::ToZero), Some(dec!(0)));
assert_eq!(value.round_sf_with_strategy(1, RoundingStrategy::ToZero), Some(dec!(300)));
assert_eq!(value.round_sf_with_strategy(2, RoundingStrategy::ToZero), Some(dec!(300)));
assert_eq!(value.round_sf_with_strategy(3, RoundingStrategy::ToZero), Some(dec!(305)));
assert_eq!(value.round_sf_with_strategy(4, RoundingStrategy::ToZero), Some(dec!(305.4)));
assert_eq!(value.round_sf_with_strategy(5, RoundingStrategy::ToZero), Some(dec!(305.45)));
assert_eq!(value.round_sf_with_strategy(6, RoundingStrategy::ToZero), Some(dec!(305.459)));
assert_eq!(value.round_sf_with_strategy(7, RoundingStrategy::ToZero), Some(dec!(305.4590)));
assert_eq!(Decimal::MAX.round_sf_with_strategy(1, RoundingStrategy::ToZero), Some(dec!(70000000000000000000000000000)));

let value = dec!(0.012301);
assert_eq!(value.round_sf_with_strategy(3, RoundingStrategy::AwayFromZero), Some(dec!(0.0124)));

pub fn unpack(&self) -> UnpackedDecimal

Convert Decimal to an internal representation of the underlying struct. This is useful for debugging the internal state of the object.

Important Disclaimer

This is primarily intended for library maintainers. The internal representation of a Decimal is considered “unstable” for public use.

Example

let pi = dec!(3.1415926535897932384626433832);
assert_eq!(format!("{:?}", pi), "3.1415926535897932384626433832");
assert_eq!(format!("{:?}", pi.unpack()), "UnpackedDecimal { \
    negative: false, scale: 28, hi: 1703060790, mid: 185874565, lo: 1102470952 \
}");

Trait Implementations

impl Add for Decimal

type Output = Decimal

The resulting type after applying the + operator.

fn add(self, rhs: Decimal) -> Decimal

Performs the + operation.

impl AddAssign for Decimal

fn add_assign(&mut self, rhs: Decimal)

Performs the += operation.

impl Clone for Decimal

fn clone(&self) -> Decimal

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Copy for Decimal

impl Debug for Decimal

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

Formats the value using the given formatter.

impl Default for Decimal

fn default() -> Decimal

Returns the “default value” for a type.

impl Deref for Decimal

type Target = Decimal

The resulting type after dereferencing.

fn deref(&self) -> &<Decimal as Deref>::Target

Dereferences the value.

impl<'de> Deserialize<'de> for Decimal

fn deserialize<D>( deserializer: D, ) -> Result<Decimal, <D as Deserializer<'de>>::Error>

where D: Deserializer<'de>,

Deserialize this value from the given Serde deserializer.

impl Display for Decimal

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

Formats the value using the given formatter.

impl Eq for Decimal

impl From<Decimal> for Decimal

fn from(value: Decimal) -> Decimal

Converts to this type from the input type.

impl From<i32> for Decimal

fn from(value: i32) -> Decimal

Converts to this type from the input type.

impl From<u8> for Decimal

fn from(value: u8) -> Decimal

Converts to this type from the input type.

impl FromStr for Decimal

type Err = <Decimal as FromStr>::Err

The associated error which can be returned from parsing.

fn from_str(src: &str) -> Result<Decimal, <Decimal as FromStr>::Err>

Parses a string s to return a value of this type.

impl Hash for Decimal

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

where __H: Hasher,

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<__RhsT> Mul<__RhsT> for Decimal

where Decimal: Mul<__RhsT, Output = Decimal>,

type Output = Decimal

The resulting type after applying the * operator.

fn mul(self, rhs: __RhsT) -> Decimal

Performs the * operation.

impl Ord for Decimal

fn cmp(&self, other: &Decimal) -> Ordering

This method returns an Ordering between self and other.

fn max(self, other: Self) -> Self

where Self: Sized,

Compares and returns the maximum of two values.

fn min(self, other: Self) -> Self

where Self: Sized,

Compares and returns the minimum of two values.

fn clamp(self, min: Self, max: Self) -> Self

where Self: Sized,

Restrict a value to a certain interval.

impl PartialEq for Decimal

fn eq(&self, other: &Decimal) -> 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 for Decimal

fn partial_cmp(&self, other: &Decimal) -> 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 Decimal

fn serialize<S>( &self, serializer: S, ) -> Result<<S as Serializer>::Ok, <S as Serializer>::Error>

where S: Serializer,

Serialize this value into the given Serde serializer.

impl StructuralPartialEq for Decimal

impl Sub for Decimal

type Output = Decimal

The resulting type after applying the - operator.

fn sub(self, rhs: Decimal) -> Decimal

Performs the - operation.

impl TryFrom<f64> for Decimal

type Error = Error

The type returned in the event of a conversion error.

fn try_from(value: f64) -> Result<Decimal, Error>

Performs the conversion.