Enum Meta 

pub enum Meta {
    Identifier(String),
    Value(MetaValue),
    Array(Vec<Meta>),
    Map(HashMap<String, Meta>),
    Named(String, Box<Meta>),
}

A tree of annotations. See the module docs.

Variants

Identifier(String)

A bare name, such as serialize.

Value(MetaValue)

A literal, such as 42 or 'foo'.

Array(Vec<Meta>)

An ordered list, written [a, b].

Map(HashMap<String, Meta>)

Named entries, written {a: 1, b: 2}.

Named(String, Box<Meta>)

A single named entry, written a = 1.

Implementations

impl Meta

pub fn parse(content: &str) -> Result<Meta, String>

Parses metadata from text, returning the parser error as a message.

pub fn as_identifier(&self) -> Option<&str>

Returns the identifier, or None for any other kind.

pub fn as_value(&self) -> Option<&MetaValue>

Returns the literal, or None for any other kind.

pub fn as_array(&self) -> Option<&Vec<Meta>>

Returns the list, or None for any other kind.

pub fn as_map(&self) -> Option<&HashMap<String, Meta>>

Returns the map, or None for any other kind.

pub fn as_named(&self) -> Option<(&str, &Meta)>

Returns the name and its value, or None for any other kind.

pub fn has_id(&self, name: &str) -> bool

Returns true when this tree mentions name, as an identifier, a string, a map key or a named entry.

Searches one level into arrays. This is the usual predicate for a metadata query.

pub fn extract_by_id(&self, name: &str) -> Option<MetaExtract<'_>>

Returns what is stored under name, or None when it is absent.

pub fn items_iter(&self) -> MetaExtractIter<'_>

Iterates the immediate children, treating a leaf as a single item.

Trait Implementations

impl Clone for Meta

fn clone(&self) -> Meta

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for Meta

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

Formats the value using the given formatter.

impl<'de> Deserialize<'de> for Meta

fn deserialize<__D>( __deserializer: __D, ) -> Result<Meta, <__D as Deserializer<'de>>::Error>

where __D: Deserializer<'de>,

Deserialize this value from the given Serde deserializer.

impl Display for Meta

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

Formats the value using the given formatter.

impl PartialEq for Meta

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

Equality operator ==.

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

Inequality operator !=.

impl Serialize for Meta

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 Meta