Module doc 

The document model: a twig::Editor plus a byte-offset caret and selection.

Where bough moves a selection through the tree, leaf moves a caret through the characters — a normal text editor’s model — and expresses every mutation as one of twig’s offset-addressed ops:

• typing / delete → edit_range(start, end, text) (P0)
• re-anchoring → the returned Change (P1)
• cursor context → node_at / ancestors_at (P3)
• the toolbar → wrap_range/toggle_inline/set_block, toggle_block_container/insert_link (P5)

twig reparses after every edit and leaves everything outside the splice byte-for-byte untouched, so the document stays a live, navigable AST while you type into it.

Structs

Capabilities

Which of leaf’s authoring controls this document’s format can actually spell — one flag per toolbar button, resolved once so a frontend can build its chrome instead of discovering each refusal on a click.

Doc

FootnoteDef

A footnote definition and the reference that sends a reader to it — the answer to Doc::footnote_definition_at, and the other half of the round trip FootnoteRef starts.

FootnoteRef

A footnote reference and the note it names — the answer to Doc::footnote_at.

InlineMarks

The inline marks in force at a point in the document — what a toolbar lights up. A Copy bitset rather than a HashSet, because Doc::active_inline_marks is called on every frame that draws a toolbar and a set that allocates to answer “is Bold on?” is a set that shouldn’t.

Landing

Where a locator lands — the answer to Doc::locate.

Enums

DiskState

What the file behind a document looks like right now, against the bytes leaf last read from it or wrote to it — the question a frontend asks before it saves (a Changed file plus a dirty document is an overwrite about to happen) or when its window regains focus. See Doc::disk_state.

LineFlow

How the WYSIWYG view treats a soft break — a bare newline inside a paragraph. An axis of its own, orthogonal to MarkupMode (which governs inline-markup delimiters) and to View: any reveal preference pairs with either flow. The renderer consults it when it lays a block’s inline content into visual rows.

MarkupMode

How much of the source markup the WYSIWYG view exposes — a per-editor preference, orthogonal to View. Named for markup rather than for Markdown because leaf is grammar-agnostic: twig hands it Djot, HTML and XML on the same terms, and every rung below is about delimiters, whatever grammar spells them. The examples are Markdown only because that is what most documents are.

View

Which view the body shows.