Struct ValueKey 

pub struct ValueKey<'a>(/* private fields */);

A key for looking up elements in Value arrays and maps.

ValueKey is the parameter type of Value::get, Value::get_mut, Value::remove, Value::contains, and the Index/IndexMut implementations on Value. You rarely name it directly: it converts from the same inputs that build a Value, so the same arguments work for both.

Where building a Value from a reference would copy, ValueKey borrows instead, so a lookup allocates nothing:

• &str, &String, &[u8], &[u8; N] borrow the string data.
• &Value borrows the value.
• &[Value], &Vec<Value>, &[Value; N], &Array borrow an array-valued key; &Map and &BTreeMap<Value, Value> borrow a map-valued key, bypassing the full-Value allocation a composite key would otherwise need.

Integers, floats, bool, SimpleValue, (), char, and owned inputs (an owned Value, String, Vec<u8>, Array, Map, and so on) are taken by value.

Examples

use cbor_core::{Value, array, map};

let a = array![10, 20, 30];
assert_eq!(a[1].to_u32(), Ok(20));

let m = map! { "x" => 10, 2 => 20 };
assert_eq!(m["x"].to_u32(), Ok(10));
assert_eq!(m[2].to_u32(), Ok(20));

let k: [Value; _] = [1,2,3].map(Value::from);
let m = map! { k.clone() => "array as key" };
assert_eq!(m[&k].as_str(), Ok("array as key") );

let mut v = array![1, 2, 3];
v.remove(0);
assert_eq!(v.len(), Some(2));

Trait Implementations

impl<'a> Debug for ValueKey<'a>

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

Formats the value using the given formatter.

impl<'a, T, const N: usize> From<&'a [T; N]> for ValueKey<'a>

where ValueKey<'a>: From<&'a [T]>,

fn from(value: &'a [T; N]) -> Self

Converts to this type from the input type.

impl<'a> From<&'a [Value<'a>]> for ValueKey<'a>

fn from(value: &'a [Value<'a>]) -> Self

Converts to this type from the input type.

impl<'a> From<&'a [u8]> for ValueKey<'a>

fn from(value: &'a [u8]) -> Self

Converts to this type from the input type.

impl<'a> From<&'a Array<'a>> for ValueKey<'a>

fn from(value: &'a Array<'a>) -> Self

Converts to this type from the input type.

impl<'a> From<&'a BTreeMap<Value<'a>, Value<'a>>> for ValueKey<'a>

fn from(value: &'a BTreeMap<Value<'a>, Value<'a>>) -> Self

Converts to this type from the input type.

impl<'a> From<&'a ByteString<'a>> for ValueKey<'a>

fn from(value: &'a ByteString<'a>) -> Self

Converts to this type from the input type.

impl<'a> From<&'a DateTime> for ValueKey<'a>

fn from(value: &'a DateTime) -> Self

Converts to this type from the input type.

impl<'a> From<&'a Map<'a>> for ValueKey<'a>

fn from(value: &'a Map<'a>) -> Self

Converts to this type from the input type.

impl<'a> From<&'a String> for ValueKey<'a>

fn from(value: &'a String) -> Self

Converts to this type from the input type.

impl<'a> From<&'a TextString<'a>> for ValueKey<'a>

fn from(value: &'a TextString<'a>) -> Self

Converts to this type from the input type.

impl<'a> From<&'a Value<'a>> for ValueKey<'a>

fn from(value: &'a Value<'a>) -> Self

Converts to this type from the input type.

impl<'a, T> From<&'a Vec<T>> for ValueKey<'a>

where ValueKey<'a>: From<&'a [T]>,

fn from(value: &'a Vec<T>) -> Self

Converts to this type from the input type.

impl<'a> From<&'a str> for ValueKey<'a>

fn from(value: &'a str) -> Self

Converts to this type from the input type.

impl<'a, const N: usize> From<[Value<'a>; N]> for ValueKey<'a>

fn from(value: [Value<'a>; N]) -> Self

Converts to this type from the input type.

impl<'a, const N: usize> From<[u8; N]> for ValueKey<'a>

fn from(value: [u8; N]) -> Self

Converts to this type from the input type.

impl<'a> From<()> for ValueKey<'a>

fn from(value: ()) -> Self

Converts to this type from the input type.

impl<'a> From<Array<'a>> for ValueKey<'a>

fn from(value: Array<'a>) -> Self

Converts to this type from the input type.

impl<'a> From<BTreeMap<Value<'a>, Value<'a>>> for ValueKey<'a>

fn from(value: BTreeMap<Value<'a>, Value<'a>>) -> Self

Converts to this type from the input type.

impl<'a> From<BigInt> for ValueKey<'a>

Available on crate feature num-bigint only.

fn from(value: BigInt) -> Self

Converts to this type from the input type.

impl<'a> From<BigUint> for ValueKey<'a>

Available on crate feature num-bigint only.

fn from(value: BigUint) -> Self

Converts to this type from the input type.

impl<'a> From<Box<[Value<'a>]>> for ValueKey<'a>

fn from(value: Box<[Value<'a>]>) -> Self

Converts to this type from the input type.

impl<'a> From<Box<[u8]>> for ValueKey<'a>

fn from(value: Box<[u8]>) -> Self

Converts to this type from the input type.

impl<'a> From<Box<str>> for ValueKey<'a>

fn from(value: Box<str>) -> Self

Converts to this type from the input type.

impl<'a> From<ByteString<'a>> for ValueKey<'a>

fn from(value: ByteString<'a>) -> Self

Converts to this type from the input type.

impl<'a> From<Cow<'a, [u8]>> for ValueKey<'a>

fn from(value: Cow<'a, [u8]>) -> Self

Converts to this type from the input type.

impl<'a> From<Cow<'a, str>> for ValueKey<'a>

fn from(value: Cow<'a, str>) -> Self

Converts to this type from the input type.

impl<'a> From<DateTime> for ValueKey<'a>

fn from(value: DateTime) -> Self

Converts to this type from the input type.

impl<'a> From<EpochTime> for ValueKey<'a>

fn from(value: EpochTime) -> Self

Converts to this type from the input type.

impl<'a> From<Float> for ValueKey<'a>

fn from(value: Float) -> Self

Converts to this type from the input type.

impl<'a, const LIMBS: usize> From<Int<LIMBS>> for ValueKey<'a>

where Uint<LIMBS>: Encoding,

Available on crate feature crypto-bigint only.

fn from(value: Int<LIMBS>) -> Self

Converts to this type from the input type.

impl<'a> From<Integer> for ValueKey<'a>

Available on crate feature rug only.

fn from(value: Integer) -> Self

Converts to this type from the input type.

impl<'a> From<Map<'a>> for ValueKey<'a>

fn from(value: Map<'a>) -> Self

Converts to this type from the input type.

impl<'a, const LIMBS: usize> From<NonZero<Int<LIMBS>>> for ValueKey<'a>

where Uint<LIMBS>: Encoding,

Available on crate feature crypto-bigint only.

fn from(value: NonZero<Int<LIMBS>>) -> Self

Converts to this type from the input type.

impl<'a, const LIMBS: usize> From<NonZero<Uint<LIMBS>>> for ValueKey<'a>

where Uint<LIMBS>: Encoding,

Available on crate feature crypto-bigint only.

fn from(value: NonZero<Uint<LIMBS>>) -> Self

Converts to this type from the input type.

impl<'a> From<SimpleValue> for ValueKey<'a>

fn from(value: SimpleValue) -> Self

Converts to this type from the input type.

impl<'a> From<String> for ValueKey<'a>

fn from(value: String) -> Self

Converts to this type from the input type.

impl<'a> From<TextString<'a>> for ValueKey<'a>

fn from(value: TextString<'a>) -> Self

Converts to this type from the input type.

impl<'a, const LIMBS: usize> From<Uint<LIMBS>> for ValueKey<'a>

where Uint<LIMBS>: Encoding,

Available on crate feature crypto-bigint only.

fn from(value: Uint<LIMBS>) -> Self

Converts to this type from the input type.

impl<'a> From<Value<'a>> for ValueKey<'a>

fn from(value: Value<'a>) -> Self

Converts to this type from the input type.

impl<'a> From<Vec<Value<'a>>> for ValueKey<'a>

fn from(value: Vec<Value<'a>>) -> Self

Converts to this type from the input type.

impl<'a> From<Vec<u8>> for ValueKey<'a>

fn from(value: Vec<u8>) -> Self

Converts to this type from the input type.

impl<'a> From<bool> for ValueKey<'a>

fn from(value: bool) -> Self

Converts to this type from the input type.

impl<'a> From<char> for ValueKey<'a>

fn from(value: char) -> Self

Converts to this type from the input type.

impl<'a> From<f16> for ValueKey<'a>

Available on crate feature half only.

fn from(value: f16) -> Self

Converts to this type from the input type.

impl<'a> From<f32> for ValueKey<'a>

fn from(value: f32) -> Self

Converts to this type from the input type.

impl<'a> From<f64> for ValueKey<'a>

fn from(value: f64) -> Self

Converts to this type from the input type.

impl<'a> From<i128> for ValueKey<'a>

fn from(value: i128) -> Self

Converts to this type from the input type.

impl<'a> From<i16> for ValueKey<'a>

fn from(value: i16) -> Self

Converts to this type from the input type.

impl<'a> From<i32> for ValueKey<'a>

fn from(value: i32) -> Self

Converts to this type from the input type.

impl<'a> From<i64> for ValueKey<'a>

fn from(value: i64) -> Self

Converts to this type from the input type.

impl<'a> From<i8> for ValueKey<'a>

fn from(value: i8) -> Self

Converts to this type from the input type.

impl<'a> From<isize> for ValueKey<'a>

fn from(value: isize) -> Self

Converts to this type from the input type.

impl<'a> From<u128> for ValueKey<'a>

fn from(value: u128) -> Self

Converts to this type from the input type.

impl<'a> From<u16> for ValueKey<'a>

fn from(value: u16) -> Self

Converts to this type from the input type.

impl<'a> From<u32> for ValueKey<'a>

fn from(value: u32) -> Self

Converts to this type from the input type.

impl<'a> From<u64> for ValueKey<'a>

fn from(value: u64) -> Self

Converts to this type from the input type.

impl<'a> From<u8> for ValueKey<'a>

fn from(value: u8) -> Self

Converts to this type from the input type.

impl<'a> From<usize> for ValueKey<'a>

fn from(value: usize) -> Self

Converts to this type from the input type.