Cursorposities

Cursorposities is a term used in discussions of text editing systems to denote any possible position of the text insertion caret within a document. A cursorposity is typically specified either as an absolute offset from the start of the document or as a coordinate such as a line and column. In line-based editors, the line/column representation is natural, while in buffer models that store raw bytes, the offset may be the primary representation.

The concept underpins how editors handle cursor movement, text selection, and editing operations. Editors must translate between coordinate representations and the underlying storage, especially when dealing with variable-width characters and Unicode grapheme clusters. For example, moving by a single character may cross code point boundaries or grapheme boundaries, affecting the resulting cursorposity.

In modern editing environments there may be multiple cursorposities when using multiple cursors or selections, each representing an insertion point. The term can also be extended to describe permissible zones within structured documents, such as within a paragraph, inside a code block, or at the start or end of a selection. Data structures used to store and render text, such as gap buffers, piece tables, or ropes, influence how cursorposities are updated efficiently.

Applications of the cursorposity concept include rendering the caret, guiding incremental parsing, and implementing features like syntax highlighting, folding, or spell checking tied to a specific position. While not universally standardized, cursorposities provide a useful abstraction for modeling textual editing positions across user interfaces and APIs. See also: cursor position, caret, byte offset, grapheme cluster.