It doesn't matter if you're an Emacs militant or a pacifist!

Proof General is designed to be useful for novices and expert users alike.
It will be useful to you if you use a proof assistant, and you'd like an interface with the following features: simplified interaction, script management, multiple file scripting, proof by pointing, toolbar and menus, syntax highlighting, real symbols, functions menu, tags, and finally, adaptability.
Are you convinced yet? If not, read on…

Proof General is designed for proof assistants which have a command-line shell interpreter. When using Proof General, the proof assistant's shell is hidden from the user. Communication takes place via three buffers (Emacs text widgets). The script buffer holds input, the commands to construct a proof. The goals buffer displays the current list of subgoals to be solved. The response buffer displays other output from the proof assistant. By default, only two of these three buffers are displayed at once. This means that the user only sees the output from the most recent interaction, rather than a screen full of output from the proof assistant.

Despite this more friendly communication model, Proof General does not commandeer the proof assistant shell: the user still has complete access to it if necessary.

A proof script is a sequence of commands sent to a proof assistant to construct a proof, usually stored in a file. Script management connects the editing of a proof script directly to an interactive proof process, maintaining consistency between the edit buffer and the state of the proof assistant.

Proof General colours a proof script to show the state in the proof assistant. Parts of a proof script that have been processed are displayed in blue and are "locked" -- they cannot be edited. Parts of the script currently being processed by the proof assistant are shown in red. Proof General has commands for processing new parts of the buffer, or undoing already processed parts.

Take a look at these screenshots of Proof General to see script managament in action.

Script management in Proof General can work across many script files. When a script is visited in the editor, it is locked (coloured) to reflect whether the proof assistant has loaded it in this session. When a file is unlocked, all of the files which depend on it are automatically unlocked too.

Dependencies between script files are either communicated from the proof assistant to Proof General, or maintained automatically by Proof General (based on the order in which files were processed).

Proof by pointing allows you to click on a subterm of a goal to be proved, and apply an appropriate rule or tactic automatically.

Proof by pointing uses the interface to highlight subterms under the mouse, and sends messages asking the prover for hints to proceed. Proof General also uses the subterm structure to make it easy to cut and paste from complicated terms.

Proof General has a toolbar with buttons for examining the proof state, starting a proof, manoeuvring in the proof script, restarting the prover, saving a proof, searching for a theorem, issuing a command, interrupting the assistant, and getting help.

Using the toolbar, you can replay proofs without knowing any low-level commands of the proof assistant or any Emacs hot-keys!

Additionally, the toolbar commands and many more besides are available on menus; you don't need to know magical key presses for any features.

Syntax highlighting is an editing feature which decorates a file with different colours or fonts according to the syntax of some language (usually a programming language).

Proof General decorates proof scripts: proof commands are highlighted and different fonts may be used for definitions and assumptions, for example.

Proof General has a close integration with the powerful X-Symbol package, which makes it easy to transparently use real symbols and Greek letters in your proofs.
Instead of seeing "not P", you see "¬ P", instead of "a * b", you see "a × b", etc.
[the examples above are simple so they will work on most browsers without needing images]

A pull-down menu gives easy navigations to theorems, definitions, and declarations proved in the current buffer.

Sometimes you may want to run a proof assistant on a powerful remote machine. Proof General can communicate with a proof assistant running remotely, while your files and editor reside on your local machine.

Tags are an editing feature which allow you to quickly locate the definition or declaration of a particular identifier. Proof General is supplied with utilities to make tag indexes for Emacs, for the proof assistants LEGO and Coq. This makes it easy to quickly access definitions from a standard library, for example, and in large proof developments split across multiple files.

Proof General is designed to be adaptable. Many aspects of its behaviour can be easily customized (using dialogue boxes and buttons, no text file editing!).

Most importantly, Proof General is generic, so you can adapt it to a new proof assistant with surprisingly little effort.

Adapting for a new proof assistant is mainly a matter of setting some variables with regular expressions to help parse output from the prover, and setting other variables with commands to send to the prover. See this basic . To get the most from Proof General (proof by pointing, for example), it may be necessary to put some hooks in the output routines of the proof assistant.

Please feel free to download Proof General to customize it for a new system, and how you get on.

For (even) more details of the above features, see the