Struct tracing::field::FieldSet

pub struct FieldSet { /* fields omitted */ }

Describes the fields present on a span.

Methods

impl FieldSet

pub const fn new(
    names: &'static [&'static str],
    callsite: Identifier
) -> FieldSet

Constructs a new FieldSet with the given array of field names and callsite.

pub fn field<Q>(&self, name: &Q) -> Option<Field> where
    Q: Borrow<str> + ?Sized, 

Returns the Field named name, or None if no such field exists.

pub fn contains(&self, field: &Field) -> bool

Returns true if self contains the given field.

Note: If field shares a name with a field in this FieldSet, but was created by a FieldSet with a different callsite, this FieldSet does not contain it. This is so that if two separate span callsites define a field named "foo", the Field corresponding to "foo" for each of those callsites are not equivalent.

Important traits for Iter

impl Iterator for Iter type Item = Field;

pub fn iter(&self) -> Iter

Returns an iterator over the Fields in this FieldSet.

pub fn len(&self) -> usize

Returns the number of fields in this FieldSet.

pub fn is_empty(&self) -> bool

Returns whether or not this FieldSet has fields.

Trait Implementations

impl<'a> IntoIterator for &'a FieldSet

type IntoIter = Iter

Which kind of iterator are we turning this into?

type Item = Field

The type of the elements being iterated over.

fn into_iter(self) -> <&'a FieldSet as IntoIterator>::IntoIter

Creates an iterator from a value.

impl Debug for FieldSet

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

Formats the value using the given formatter.

impl Display for FieldSet

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

Formats the value using the given formatter.