Enum ConstValue 

#[non_exhaustive]
pub enum ConstValue {
    Boolean(bool),
    Integer(i128),
    Float {
        mantissa: String,
        exponent: Option<String>,
    },
    Fixed {
        digits: String,
        scale: u8,
    },
    Char(char),
    WChar(u32),
    String(String),
    WString(Vec<u32>),
}

A constant expression’s value, in the form the expression had.

Ast::eval_integral answers for the constants that are numbers a wire format cares about, and returns EvalError::NotIntegral for the rest. That is the right answer where an integer is required — an array bound, a @bit_bound, a case label — and the wrong one where the question is only “what does this constant say”: const string MODULE_ID = "spatial.sensing.lidar/1.5"; is a perfectly evaluated constant that no integer represents, and a backend that asked the integral question could not emit it at all.

Variants (Non-exhaustive)

Non-exhaustive enums could have additional variants added in future. Therefore, when matching against variants of non-exhaustive enums, an extra wildcard arm must be added to account for any future variants.

Boolean(bool)

TRUE / FALSE.

Integer(i128)

An integer, including a character or an enumerator evaluated as one, and every arithmetic expression over them.

Float

A floating-point literal, in the two halves it was written in.

Kept as text: the decimal a source wrote and the nearest f64 are two different values, and which one a backend needs is the backend’s business.

Fields

mantissa: String

Mantissa exactly as written, including any trailing point.

exponent: Option<String>

Exponent as written, without the e.

Fixed

A fixed-point literal — a decimal, and never a binary float.

Fields

digits: String

Digits as written, without the point.

scale: u8

Digits after the point.

Char(char)

A narrow character.

WChar(u32)

A wide character, as a code point.

String(String)

A narrow string, with escapes resolved.

WString(Vec<u32>)

A wide string, as code points.

Trait Implementations

impl Clone for ConstValue

fn clone(&self) -> Self

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for ConstValue

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

Formats the value using the given formatter.

impl PartialEq for ConstValue

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

Equality operator ==.

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

Inequality operator !=.

impl StructuralPartialEq for ConstValue