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 is_empty(&self) -> bool

true if there are no keys.

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

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

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 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 (§4.1). 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 §5.2 requires.

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

The verification with the latest parseable at (§5.2).

pub fn trust_tier(&self) -> TrustTier

The trust tier derived from verified (§5.3).

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

When the content last meaningfully changed: generated.at (§5.2), falling back to a legacy v0.1 timestamp when generated is absent, as §13.1 permits.

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

The legacy v0.1 timestamp field, superseded by generated.at (§13.1).

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 (§5.4).

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

The stale_after date, on and after which the content is stale (§5.5).

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

Whether the concept is stale on today: today >= stale_after (§5.5). A concept with no (or an unreadable) stale_after is never stale.

A datetime-valued stale_after is compared on its date part, as DateField::effective_date explains.

pub fn is_attested_computation(&self) -> bool

true when type is Attested Computation (§10.1).

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 (§10.3).

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 (§6.2), as (field name, raw value).

sources[].resource is deliberately excluded: it may be a scope descriptor rather than a path (§5.1). 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 (§4.1).

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

Returns the legacy v0.1 keys present that v0.2 supersedes (§13.1).

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 From<Mapping> for Frontmatter

fn from(map: Mapping) -> Self

Converts to this type from the input 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