The Emacs Widget Library: A Critique and Case Study

The Emacs widget library (widget.el) excels at defining widget types through inheritance but lacks layout primitives and state management. Building complex UIs requires manual coordinate tracking, full redraws on changes, and careful cursor position preservation. A detailed walkthrough demonstrates building a table widget with editable cells, revealing patterns like measuring widgets in temporary buffers and storing row/column indices. The author created widget-extra and vui.el libraries to address these limitations while maintaining the underlying performance benefits.