Struct StatementMap 

pub struct StatementMap { /* private fields */ }

The statement-boundary map for one element stream: boundary_after(i) says a statement ends in the gap after element i. Boundaries sit on whole top-level siblings — a boundary never splits a CST node, so anything the greedy parser over-attached to a consumed sibling rides along in its statement.

Implementations

impl StatementMap

pub fn boundary_after(&self, idx: usize) -> bool

Whether a statement boundary sits in the gap after element idx.

pub fn glue_before(&self, idx: usize) -> bool

Whether the gap before element idx must render unbreakable. Set for a recognized-head COMMAND sitting mid-way through a fallback statement: a width wrap at that gap would start a printed line with the recognized head, which the next pass segments as its own statement mid-way through this one and the passes disagree (l3fp-trig.dtx’s \@@_sep:-delimited protocols, xo-or.dtx’s =~ \exp_not:c {…}\space trace lines). Every other fallback gap stays breakable: a printed continuation line starting with anything unrecognized re-segments to exactly that line and renders to itself, the fallback’s fixed point.

pub fn is_glued(&self, idx: usize) -> bool

Whether element idx belongs to a recognized statement that absorbed trailing same-line material ([absorb_trailing_junk]) — a call unit followed by unrecognized tokens or a comment on its authored line (xparse’s \bool_if:NTF … { \cs_set:cpn } … ##1 \q_@@ … definition trickery). Such a statement renders with every top-level gap unbreakable: its junk extent is newline-keyed (the fallback’s Tier-2 residue), so a width wrap moving material across a line boundary would change the extent — and with it the trailing-command glue decision — on the next pass. All-hard gaps preserve the authored line shape (node-internal layout still breaks freely and re-reads node-internal), which is a fixed point by construction.

pub fn is_fallback(&self, idx: usize) -> bool

Whether element idx belongs to a fallback statement. A fallback line commits as a plain greedy fill, never the sticky fill structural statements use: greedy packing is self-fulfilling (each printed line re-segments to a fallback statement that re-fills to exactly itself), while a sticky cascade forces atoms that would fit onto their own broken lines — a shape the next pass’s shorter per-line statements do not reproduce.