Struct Span 

pub struct Span {
    pub line: u16,
    pub left: u16,
    pub right: u16,
    pub cells: Vec<Cell>,
    pub combining: BTreeMap<usize, Vec<char>>,
    pub links: BTreeMap<usize, NonZeroU32>,
    pub ucolors: BTreeMap<usize, Color>,
}

A damaged column run on one line, with its cells.

combining and links map a span-relative column to what that cell carries — combining clusters (#45) and hyperlinks (#46) live in per-row maps, so neither rides the cell. Since v14 (#621) both are sparse wire groups of their own, not indices in the cell record, which is what removed the u16 ceilings the engine could legitimately exceed.

The two are deliberately not symmetric, and the asymmetry is measured rather than stylistic:

• combining holds the cluster inline. Term::frame pushes one entry per combining cell with no interning, so an index bought nothing but a level of indirection and a table to count. Inlining is size-neutral (measured: −0.5% on a combining-heavy frame) and buys the deletion of both.
• links holds a 1-based index into Frame::link_table, because that table is interned (Term::frame’s link_remap ships each referenced URI once). Inlining a URI at every linked cell was measured at +171…403% on link-dense frames, and all three references share one copy across cells — ghostty ref-counts its hyperlink set explicitly “so that a set of cells can share the same hyperlink without duplicating the data”, xterm.js keys cells to an OscLinkService id, alacritty holds Arc<HyperlinkInner>.

A column is present in either map iff its cell carries the matching bit — and, as with ucolors below, that bit does not travel on the wire (the record encodes cell.c() and encode_color(bg), which drop C_COMBINED and LINK_PRESENT respectively). decode re-arms both from these maps’ own entries. A Span built by hand for a test owes the same pairing.

Fields

line: u16

left: u16

right: u16

cells: Vec<Cell>

combining: BTreeMap<usize, Vec<char>>

links: BTreeMap<usize, NonZeroU32>

ucolors: BTreeMap<usize, Color>

Underline colours (SGR 58, #520): span-relative column → the Color reference the cell’s coloured underline draws in. Sparse — only cells that carry a non-default underline colour appear (gated on the UNDERLINE attribute at parse time). Unlike combining/links this is a colour reference, not a side-table index, so it ships inline (no _table on the Frame). Kept off the per-cell record so a plain-text frame pays nothing (ADR-0020: no inert per-cell payload).

Like combining and links, a column here is present iff its cell carries the matching bit (Cell::is_ucolored) — but that bit does not travel on the wire (encode_color keeps only mode+value, and CellFlags holds no presence bits), so decode re-arms it from this map’s own entries. A Span built by hand for a test owes the same pairing: an entry here without Cell::set_ucolored on the cell is a column the gated readers cannot see. (#531)

Trait Implementations

impl Clone for Span

fn clone(&self) -> Span

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for Span

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

Formats the value using the given formatter.

impl Eq for Span

impl PartialEq for Span

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

Equality operator ==.

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

Inequality operator !=.

impl StructuralPartialEq for Span