Struct Frontmatter 

pub struct Frontmatter { /* private fields */ }

A concept’s frontmatter: an ordered key/value mapping with typed accessors for the well-known OKF fields.

Implementations

impl Frontmatter

pub const fn new() -> Self

Creates an empty frontmatter block.

pub const fn from_mapping(map: Mapping) -> Self

Wraps an existing mapping.

pub const fn as_mapping(&self) -> &Mapping

Borrows the underlying ordered mapping.

pub const fn as_mapping_mut(&mut self) -> &mut Mapping

Mutably borrows the underlying ordered mapping.

pub fn into_mapping(self) -> Mapping

Consumes the wrapper, returning the underlying mapping.

pub const fn len(&self) -> usize

Number of frontmatter keys.

pub const fn is_empty(&self) -> bool

true if there are no keys.

pub fn contains_key(&self, key: &str) -> bool

true if frontmatter contains the given key.

pub fn iter(&self) -> impl Iterator<Item = (&Value, &Value)>

Iterates over frontmatter (key, value) pairs in order.

pub fn keys(&self) -> impl Iterator<Item = &str>

Iterates over frontmatter string keys in order.

pub fn values(&self) -> impl Iterator<Item = &Value>

Iterates over frontmatter values in order.

pub fn get(&self, key: &str) -> Option<&Value>

Raw value for an arbitrary key (including producer extensions).

pub fn get_mut(&mut self, key: &str) -> Option<&mut Value>

Looks up a mutable value by string key.

pub fn set(&mut self, key: impl Into<String>, value: Value)

Sets a raw value for a key, preserving position if it already exists.

pub fn remove(&mut self, key: &str) -> Option<Value>

Removes a key from frontmatter, returning the removed value if present.

pub fn reorder_preferred(&mut self)

Reorders the keys into PREFERRED_KEY_ORDER, leaving every other key after them in its current relative order.

A port of the reference implementation’s _reorder_frontmatter, which it applies whenever it writes a concept document; call this before Document::serialize to produce frontmatter laid out the same way. No key is added, dropped, or rewritten, so only the serialized order changes.

pub fn type_(&self) -> Option<Cow<'_, str>>

The required type field. None if absent or not a scalar.

Non-string scalars (type: 42) are coerced to their display form, the way the reference’s str(fm.get("type")) does, rather than read as None: the spec calls type “a short string”, so a non-string value is a producer deviation, but a consumer still gets something to route on rather than treating the concept as typeless.

pub fn title(&self) -> Option<Cow<'_, str>>

The optional title field.

pub fn description(&self) -> Option<Cow<'_, str>>

The optional one-line description.

pub fn resource(&self) -> Option<Cow<'_, str>>

The optional resource URI for the underlying asset.

pub fn tags(&self) -> Vec<String>

The optional tags list. Non-string elements are coerced to their display form; a non-sequence tags value yields an empty vector.

pub fn sources(&self) -> Vec<Source>

The sources entries: the materials this concept derives from.

pub fn usage_window(&self) -> Option<UsageWindow>

The shared usage_window that frames every sources[].usage_count.

pub fn generated(&self) -> Option<Generated>

The generated block: how the current content was produced.

pub fn verified(&self) -> Vec<Verification>

The verified events: who or what has confirmed this content.

A bare { by, at } mapping is returned as a one-element list, as the spec requires.

pub fn latest_verification(&self) -> Option<Verification>

The verification with the latest parseable at.

pub fn trust_tier(&self) -> TrustTier

The trust tier derived from verified.

pub fn content_changed_at(&self) -> Option<DateTimeField>

When the content last meaningfully changed: generated.at, falling back to a legacy v0.1 timestamp when generated is absent, as permitted.

pub fn timestamp(&self) -> Option<Cow<'_, str>>

The legacy v0.1 timestamp field, superseded by generated.at.

Prefer Frontmatter::content_changed_at, which reads generated.at first and falls back to this.

pub fn status(&self) -> Status

The lifecycle status. An absent key is Status::Stable.

pub fn stale_after(&self) -> Option<DateTimeField>

The stale_after timestamp, on and after which the content is stale.

pub fn is_stale_at(&self, now: DateTime) -> bool

Whether the concept is stale at now: now >= stale_after. A concept with no (or an unreadable / offset-less) stale_after is never stale.

pub fn is_stale_on(&self, today: Date) -> bool

Whether the concept is stale on today: today >= stale_after. Evaluates staleness at midnight UTC on today.

pub fn is_attested_computation(&self) -> bool

true when type is Attested Computation.

pub fn runtime(&self) -> Option<Cow<'_, str>>

The runtime: how to run the computation, and so what parameters mean. REQUIRED on an Attested Computation concept.

pub fn parameters(&self) -> Vec<Parameter>

The declared parameters an agent may fill.

pub fn computation(&self) -> Option<Cow<'_, str>>

The computation path, when the computation lives in a file rather than a body block.

pub fn executor(&self) -> Option<Executor>

The executor: how the computation is run, and what a receipt carries.

pub fn attester(&self) -> Option<Attester>

The attester: deterministic code that turns a receipt into a verdict.

pub fn path_fields(&self) -> Vec<(&'static str, String)>

The path-valued frontmatter fields present, as (field name, raw value).

sources[].resource is deliberately excluded: it may be a scope descriptor rather than a path. Use Source::resource_kind to filter those yourself.

pub fn extension_keys(&self) -> Vec<&str>

Returns the keys present that are not well-known OKF fields, i.e. the producer-defined extension keys consumers must preserve.

pub fn legacy_keys(&self) -> Vec<&str>

Returns the legacy v0.1 keys present that v0.2 supersedes.

Trait Implementations

impl Clone for Frontmatter

fn clone(&self) -> Frontmatter

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for Frontmatter

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

Formats the value using the given formatter.

impl Default for Frontmatter

fn default() -> Frontmatter

Returns the “default value” for a type.

impl Display for Frontmatter

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

Formats the value using the given formatter.

impl<'a> Extend<(&'a str, Value)> for Frontmatter

fn extend<T: IntoIterator<Item = (&'a str, Value)>>(&mut self, iter: T)

Extends a collection with the contents of an iterator.

fn extend_one(&mut self, item: A)

🔬This is a nightly-only experimental API. (extend_one)

Extends a collection with exactly one element.

fn extend_reserve(&mut self, additional: usize)

🔬This is a nightly-only experimental API. (extend_one)

Reserves capacity in a collection for the given number of additional elements.

impl Extend<(String, Value)> for Frontmatter

fn extend<T: IntoIterator<Item = (String, Value)>>(&mut self, iter: T)

Extends a collection with the contents of an iterator.

fn extend_one(&mut self, item: A)

🔬This is a nightly-only experimental API. (extend_one)

Extends a collection with exactly one element.

fn extend_reserve(&mut self, additional: usize)

🔬This is a nightly-only experimental API. (extend_one)

Reserves capacity in a collection for the given number of additional elements.

impl Extend<(Value, Value)> for Frontmatter

fn extend<T: IntoIterator<Item = (Value, Value)>>(&mut self, iter: T)

Extends a collection with the contents of an iterator.

fn extend_one(&mut self, item: A)

🔬This is a nightly-only experimental API. (extend_one)

Extends a collection with exactly one element.

fn extend_reserve(&mut self, additional: usize)

🔬This is a nightly-only experimental API. (extend_one)

Reserves capacity in a collection for the given number of additional elements.

impl From<Frontmatter> for Mapping

fn from(fm: Frontmatter) -> Self

Converts to this type from the input type.

impl From<Mapping> for Frontmatter

fn from(map: Mapping) -> Self

Converts to this type from the input type.

impl<'a> FromIterator<(&'a str, Value)> for Frontmatter

fn from_iter<T: IntoIterator<Item = (&'a str, Value)>>(iter: T) -> Self

Creates a value from an iterator.

impl FromIterator<(String, Value)> for Frontmatter

fn from_iter<T: IntoIterator<Item = (String, Value)>>(iter: T) -> Self

Creates a value from an iterator.

impl FromIterator<(Value, Value)> for Frontmatter

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

Creates a value from an iterator.

impl FromStr for Frontmatter

type Err = DocumentError

The associated error which can be returned from parsing.

fn from_str(s: &str) -> Result<Self, Self::Err>

Parses a string s to return a value of this type.

impl PartialEq for Frontmatter

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

Equality operator ==.

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

Inequality operator !=.

impl StructuralPartialEq for Frontmatter