Enum Invariant 

#[non_exhaustive]
pub enum Invariant {
    CarriageReturn,
    BidiControl(char),
    IslandSlotMismatch {
        slots: usize,
        islands: usize,
    },
    LineCountMismatch {
        lines: usize,
        segments: usize,
    },
    MarkOutOfRange {
        start: Usv,
        end: Usv,
        len: Usv,
    },
    ZeroWidthFormatting {
        at: Usv,
    },
    BadHeadingLevel(u8),
    FirstLineContinues,
    ReservedUnknownTag(String),
    ReservedUnknownLineKind(String),
    ReservedUnknownContainer(String),
    MarkEdgeOnNewline {
        at: Usv,
    },
    TableAlignsMismatch {
        aligns: usize,
        cols: usize,
    },
    TableRaggedRow {
        row: usize,
        width: usize,
        cols: usize,
    },
    TableCellNewline {
        cell: usize,
    },
    IslandIdCollision {
        id: String,
    },
    AnchorIdCollision {
        id: String,
    },
    TableHeaderNotArray,
    LineKindMismatch {
        line: usize,
        mismatch: LineKindMismatch,
    },
    NestingTooDeep {
        line: usize,
        depth: usize,
        max: usize,
    },
    JsonTooDeep {
        what: &'static str,
        max: usize,
    },
}

Ways a Content can violate its invariants. Returned by Content::validate; import normalization guarantees none of these.

Variants (Non-exhaustive)

Non-exhaustive enums could have additional variants added in future. Therefore, when matching against variants of non-exhaustive enums, an extra wildcard arm must be added to account for any future variants.

CarriageReturn

\r in the text (line endings must be normalized to \n).

BidiControl(char)

A bidi formatting control in the text.

IslandSlotMismatch

island_slot_count != islands.len().

Fields

slots: usize

islands: usize

LineCountMismatch

lines.len() != newline_segment_count.

Fields

lines: usize

segments: usize

MarkOutOfRange

A mark range runs past the content or is inverted (start > end).

Fields

start: Usv

end: Usv

len: Usv

ZeroWidthFormatting

A zero-width formatting mark survived normalization.

Fields

at: Usv

BadHeadingLevel(u8)

A heading level outside 1..=6.

FirstLineContinues

The first line has continues: true (nothing precedes it to continue).

ReservedUnknownTag(String)

An MarkKind::Unknown reused a reserved built-in type name.

ReservedUnknownLineKind(String)

A LineKind::Unknown reused a reserved built-in kind name: its serialization would parse back as the built-in, dropping its attrs.

ReservedUnknownContainer(String)

A Container::Unknown reused a reserved built-in container name, the same non-injectivity as Invariant::ReservedUnknownLineKind.

MarkEdgeOnNewline

A formatting mark edge sits on a \n (normalization should have trimmed it): a hand-built content that skipped normalize.

Fields

at: Usv

TableAlignsMismatch

A table island’s aligns length differs from its column count (the header width). normalize syncs aligns to the column count.

Fields

aligns: usize

cols: usize

TableRaggedRow

A table island body row’s width differs from the column count (the header width). normalize pads short rows (and the header) to the widest.

Fields

row: usize

width: usize

cols: usize

TableCellNewline

A table cell’s text carries a \n: cells are single-line (a newline would break the exported table). cell is the flat header-then-rows index; normalize rewrites the newline to a space.

Fields

cell: usize

IslandIdCollision

Two islands share an id. Ids are deterministic, session-stable identities (hash input, so never ambient); import mints them by index so they never collide, but a hand-built or round-tripped content can. Downstream code that keys islands by id would otherwise silently pick the wrong one. Uniqueness is the id invariant validate enforces: positional equality is not, since edits keep an island’s id stable across renumbers.

Fields

id: String

AnchorIdCollision

Two prose anchors share an id, or one carries the empty id. An anchor id is a caller-supplied, opaque handle, unique per Content (hash input, never ambient in the twin’s sense; DOCUMENT_STORAGE.md § Anchor-id identity). RemoveAnchor { id } retains-out every match, so a shared id makes removing one destroy both; the empty id is a degenerate handle. Scope is prose marks: cell anchors are outside the op surface.

Fields

id: String

TableHeaderNotArray

A table island’s header prop is present but not a JSON array: it cannot carry column cells. normalize rewrites a non-array header to an empty array (a zero-column, content-free table).

LineKindMismatch

A line’s LineKind contradicts its text. Export trusts the kind and never re-reads the segment, so an unchecked mismatch is silent text loss (an Island-tagged prose line projects to its resolved island alone).

Fields

line: usize

mismatch: LineKindMismatch

NestingTooDeep

A line’s container path is nested deeper than MAX_NESTING_DEPTH. Both emitters recurse one frame per container, so an unbounded path overflows the stack; import caps it, and this is the same cap for the content that never went through import (a decoded blob, a hand-built value).

Fields

line: usize

depth: usize

max: usize

JsonTooDeep

An opaque JSON payload (an island’s props, an unknown line/container/ mark’s attrs) nests deeper than MAX_JSON_DEPTH: Invariant::NestingTooDeep on the payload axis. what names the bag. No true depth: the check bails at the first over-deep container rather than measuring past the limit.

Fields

what: &'static str

max: usize

Trait Implementations

impl Clone for Invariant

fn clone(&self) -> Invariant

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for Invariant

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

Formats the value using the given formatter.

impl Eq for Invariant

impl PartialEq for Invariant

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

Equality operator ==.

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

Inequality operator !=.

impl StructuralPartialEq for Invariant