Struct SnippetSession 

pub struct SnippetSession { /* private fields */ }

A live snippet session: one tracked range per stop, the active stop AlwaysGrows and the rest NeverGrows. It never touches the document or history — the caller inserts the snippet text (one sealed transaction), selects the range this reports, and the session only registers / swaps / unregisters ranges. Cancellation is never a transaction: text stays, ranges unregister, nothing enters history.

Implementations

impl SnippetSession

pub fn start( snippet: &Snippet, base: u32, store: &mut DecorationStore, ) -> Option<(Self, Range<u32>)>

Start a session from a just-inserted snippet whose stop ranges are offset by base (the insert position). Registers one SnippetStop per stop (the first AlwaysGrows, the rest NeverGrows) and returns the session plus the first stop’s content for the caller to select. None — no session — when the snippet has no stop besides the final.

pub fn active_index(&self) -> usize

The ordinal (visit-order) index of the active stop.

pub fn active_range(&self, store: &DecorationStore) -> Option<Range<u32>>

The active stop’s current content range (post-edit), or None if it was dropped.

pub fn tab(&mut self, forward: bool, store: &mut DecorationStore) -> TabOutcome

Tab (forward) / Shift+Tab (!forward) between stops. Swaps stickiness on a move; Tab past the last non-final stop ends the session at the final stop (TabOutcome::Finish, ranges already unregistered).

pub fn on_caret( &mut self, offset: u32, store: &mut DecorationStore, ) -> CaretOutcome

A caret landed at offset (a click): re-activate a different stop it lands in, stay if it’s the active stop, or report that it left every stop (the caller then cancels).

pub fn edit_escapes(&self, range: &Range<u32>, store: &DecorationStore) -> bool

Whether an edit spanning range lands wholly outside every stop (→ the caller cancels). An edit touching any stop keeps the session.

pub fn cancel(&mut self, store: &mut DecorationStore)

Unregister every stop range. Cancellation is never a transaction.