Pan is a prototype and testbed for language-based editors and viewers. Its design addresses the needs of experienced users who manage complex objects such as large software systems. All of Pan's components are multi-lingual, incremental, description-driven, customizable, and extensible. Viewing is facilitated by semantics-based browsing and an object model which integrates text and structure. Pan is intended to share information with other tools, allowing integration into a larger language, program, and document development environment.

This document, a users manual, describes the basic operational facilities of Pan I, the current implementation. It explains the concepts behind Pan's editing environment, introduces editing commands, and discusses techniques for customization. Appendices list command bindings (to both keystrokes and menus), buffer options, buffer flags, and a compatibility guide for GNU Emacs users.

(September, 1986. Revised September, 1987.)