Lines (never empty, and without their newlines) and the cursor.

Zero-indexed logical (row, column) position in the buffer. Fields are row then column, so the derived Ord is document order.

Replace editRemoved at editAt with editInserted. Both texts may span lines. An edit carries what it removes, so it can be inverted without looking at the document.

A TextBuffer containing a single blank line.

Construct a TextBuffer from raw Text. Cursor is always (0, 0).

All lines joined with newlines, copied once into a new text.

The text of a row, or empty outside the document.

Move to a position, clamped into the document, without changing text.

The nearest position inside the document.

How many lines at the start and at the end are the ones there at the last markLinesSeen; the lines between may have changed. Whatever was derived per line from the marked document can be kept for those lines and rederived for the rest.

Record that every line has been seen, for changedLines.

Back over spaces (line breaks count), then over the word before them.

Forward over spaces (line breaks count), then over the word after them.

The text between two positions in document order, reading only the lines between them.

Apply an edit and leave the cursor after the inserted text. The removed text decides how far the edit reaches, so an edit recorded against this document (or undone from one) is applied without reading the text it removes.

The edit that takes the document back.

The edit replacing the text between two positions.

Text as it can enter the document: printable characters, tabs and line breaks, with Windows line ends folded.