v0.2.13

A shared Document under several editors, each with its own caret, menus and scroll. Anchors in markdown byte offsets, placed down the page whether built or not, with hover events and app washes beside them. Keyed context menus that stand off a trigger and walk submenus by arrow key. A source view that keeps its lines across frames and highlights edits off the UI thread.

New

• Document, a markdown document as its editors share it: the text, its form, its marks, its anchors and one undo stack. Editor::for_document opens an editor on one, and every editor on it shows the same text with its own caret and scroll. Editor::document is the one an editor is on; Editor::new still makes an editor on a document of its own.
• DocumentEvent reports a change to a document, and DocumentEvent::edited whether its text changed.
• Document::source_with_anchors answers the markdown to save and each anchor's range in byte offsets into it (SourceRanges), and Document::set_source_anchors takes ranges in byte offsets into the markdown the document was read from.
• Editor::anchor_tops places every anchor down the editor, built or not: an anchor whose line has not been built gets its block's top, guessed until the block is measured. BlockLayouts::top places any position the same way.
• Editor::set_washes washes ranges the app sets, such as find hits, over the anchors' own, and Editor::washes reads them back.
• EditorEvent::AnchorHovered says which anchor's text the pointer came over, or None when it leaves one.
• Editor::source_lines counts the source's lines in source mode.
• markdown::SourceText holds a source text's lines and highlight spans across frames. SourceText::edit redoes only the lines an edit touched and answers a SpanJob, which highlights the whole text on any thread for SourceText::set_spans.
• ContextMenu is keyed by a K and stands at a Place: a window point, or above or below a trigger with either edge aligned. ContextMenu::toggle opens or closes the menu a trigger owns, ContextMenu::trigger wraps the trigger, and key, showing, card, place and render_for read and draw it.
• A context menu walks into a submenu with the right arrow and back out with the left (menu::SelectChild, SelectParent).
• History::clear, History::can_undo, and Run, the run of edits an undo step coalesces.

Changed

• with_undo_limit, with_marks, with_mode, set_anchors, source_with_anchors and set_source_anchors are on Document, not Editor.
• ContextMenu is ContextMenu<V, K = ()>, and Slot is Slot<V, K>. ContextMenu::open takes the key, a Place and the choice handler; render no longer takes the handler.
• History::landed and interrupt are on Run.
• markdown::render_source takes a &SourceText instead of a &str.
• Source mode applies an edit to the lines it touched and highlights it on the background executor, showing the spans from before the edit until then.

Fixed

• Lifting custom marks out of markdown is linear in the source again, instead of quadratic in its code spans, fences and links.