Struct Fields

pub struct Fields { /* private fields */ }

Mapping of names to Fields.

Implementations

impl Fields

pub fn new() -> Self

Return a new, empty metadata field map.

pub fn is_empty(&self) -> bool

Return whether this field map contains no fields.

let mut fields = Fields::default();

assert!(fields.is_empty());

fields.insert("", Field::empty());

assert!(!fields.is_empty());

pub fn contains(&self, name: impl AsRef<str>) -> bool

Return whether this field map contains a field with the given name.

let fields: Fields = [("a thing", Field::empty())].into_iter().collect();

assert!(fields.contains("a thing"));
assert!(!fields.contains("not a thing"));

pub fn get(&self, name: impl AsRef<str>) -> Option<&Field>

Get a reference to the field with the provided name, if it exists.

let fields: Fields = [("a thing", Field::empty())].into_iter().collect();

assert!(fields.get("a thing").is_some());
assert!(fields.get("not a thing").is_none());

pub fn get_mut(&mut self, name: impl AsRef<str>) -> Option<&mut Field>

Get a mutable reference to the field with the provided name, if it exists.

let mut fields: Fields = [("a thing", Field::empty())].into_iter().collect();

assert!(fields.get_mut("a thing").is_some());
assert!(fields.get_mut("not a thing").is_none());

pub fn insert(&mut self, name: impl Into<String>, field: Field) -> Option<Field>

Insert a field with the given name into the map.

let mut fields = Fields::default();

assert!(fields.insert("field", Field::empty()).is_none());
assert!(fields.insert("field", Field::empty()).is_some());

pub fn remove(&mut self, name: impl AsRef<str>) -> Option<Field>

Remove a field with the given name from the map.

let mut fields: Fields = [("a", Field::empty())].into_iter().collect();

assert_eq!(fields.remove("a"), Some(Field::empty()));
assert_eq!(fields.remove("a"), None);

pub fn field(&mut self, name: impl Into<String>) -> &mut Field

Get a mutable reference to the field with the provided name, inserting an empty Field if it didn’t exist.

let mut fields = Fields::default();

assert!(!fields.contains("thing"));

fields.field("thing");

assert!(fields.contains("thing"));

Trait Implementations

impl Clone for Fields

fn clone(&self) -> Fields

Returns a copy of the value.

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

Performs copy-assignment from source.

impl Debug for Fields

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

Formats the value using the given formatter.

impl Default for Fields

fn default() -> Fields

Returns the “default value” for a type.

impl<'de> Deserialize<'de> for Fields

fn deserialize<__D>(__deserializer: __D) -> Result<Self, __D::Error>

where __D: Deserializer<'de>,

Deserialize this value from the given Serde deserializer.

impl<K: Into<String>> FromIterator<(K, Field)> for Fields

fn from_iter<T: IntoIterator<Item = (K, Field)>>(iter: T) -> Self

Creates a value from an iterator.

impl PartialEq for Fields

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

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

where __S: Serializer,

Serialize this value into the given Serde serializer.

impl Eq for Fields

impl StructuralPartialEq for Fields