lean2/src/emacs

Emacs mode for lean theorem prover

Requirements

lean-mode requires Emacs 24 and the following packages, which can be installed via M-x package-install.

• dash
• dash-functional
• f
• s

The following packages are optional, but we recommend installing them to use full features of lean-mode.

• company
• flycheck
• fill-column-indicator
• lua-mode
• mmm-mode

Both the optional and required packages will be installed for you automatically the first time you use lean-mode, if you follow the installation instructions below.

Installation

When Emacs is started, it loads startup information from a special initialization file, often called an "init file." The init file can be found in different places on different systems:

• Emacs will check for a file named .emacs in your home directory.
• With GNU Emacs, it is common to use .emacs.d/init.el instead.
• With Aquamacs, it is common to use ~/Library/Preferences/Aquamacs Emacs/Preferences.el.

On Windows, there are two additional complications:

• It may be hard to figure out what Emacs considers to be your "home directory".
• The file explorer may not let you create a file named .emacs, since it begins with a period.

One solution is to run Emacs itself and create the file using C-c C-f (control-C, control-F) and then entering ~/.emacs. (The tilde indicates your home directory.) On Windows, you can also name the file _emacs.

Put the following code in your Emacs init file:

(require 'package)
(add-to-list 'package-archives '("melpa" . "http://melpa.milkbox.net/packages/") t)
(when (< emacs-major-version 24)
  ;; For important compatibility libraries like cl-lib
  (add-to-list 'package-archives '("gnu" . "http://elpa.gnu.org/packages/")))
(package-initialize)

;; Install required/optional packages for lean-mode
(defvar lean-mode-required-packages
  '(company dash dash-functional flycheck f
            fill-column-indicator s lua-mode mmm-mode))
(let ((need-to-refresh t))
  (dolist (p lean-mode-required-packages)
    (when (not (package-installed-p p))
      (when need-to-refresh
        (package-refresh-contents)
        (setq need-to-refresh nil))
      (package-install p))))

Then choose your installation method from the following scenarios, and add the corresponding code to your init file:

Case 1: Build Lean from source

;; Set up lean-root path
(setq lean-rootdir "~/projects/lean")  ;; <=== YOU NEED TO MODIFY THIS
(setq-local lean-emacs-path
            (concat (file-name-as-directory lean-rootdir)
                    (file-name-as-directory "src")
                    "emacs"))
(add-to-list 'load-path (expand-file-name lean-emacs-path))
(require 'lean-mode)

Case 2: Install Lean via apt-get on Ubuntu or via dpkg on Debian

;; Set up lean-root path
(setq lean-rootdir "/usr")
(setq-local lean-emacs-path "/usr/share/emacs/site-lisp/lean")
(add-to-list 'load-path (expand-file-name lean-emacs-path))
(require 'lean-mode)

Case 3: Install Lean via homebrew on OS X

;; Set up lean-root path
(setq lean-rootdir "/usr/local")
(setq-local lean-emacs-path "/usr/local/share/emacs/site-lisp/lean")
(add-to-list 'load-path (expand-file-name lean-emacs-path))
(require 'lean-mode)

Note: if you install homebrew in a custom location that is not the default location, please run brew info lean, and it will tell you where the lean-mode files are located. With that information, update the lean-emacs-path variable accordingly.

Case 4: Install Lean in Windows

;; Set up lean-root path
(setq lean-rootdir "\\lean-0.2.0-windows")
(setq-local lean-emacs-path "\\lean-0.2.0-windows\\share\\emacs\\site-lisp\\lean")
(add-to-list 'load-path (expand-file-name lean-emacs-path))
(require 'lean-mode)

Key Bindings

Key	Function
C-c C-x	lean-std-exe
C-c C-l	lean-std-exe
C-c C-t	lean-eldoc-documentation-function
C-c C-f	lean-fill-placeholder
M-.	lean-find-tag
TAB	lean-tab-indent-or-complete
C-c C-o	lean-set-option
C-c C-e	lean-eval-cmd

Known Issues and Possible Solutions

Unicode

If you experience a problem rendering unicode symbols on emacs, please download the following fonts and install them on your machine:

• Quivira.ttf
• Dejavu Fonts
• NotoSans
• NotoSansSymbols

Then, have the following lines in your emacs setup to use DejaVu Sans Mono font:

(when (member "DejaVu Sans Mono" (font-family-list))
  (set-face-attribute 'default nil :font "DejaVu Sans Mono-11"))

You may also need to install emacs-unicode-fonts package.

• Run M-x package-refresh-contents, M-x package-install, and type unicode-fonts.

• Add the following lines in your emacs setup:

(require 'unicode-fonts) (unicode-fonts-setup)

"Variable binding depth exceeds max-specpdl-size" Error
---------------------------------------------------------

See [Issue 906](https://github.com/leanprover/lean/issues/906) for details.
[Moritz Kiefer](https://github.com/cocreature) reported that `proofgeneral` 
comes with an old version of `mmm-mode` (0.4.8, released in 2004) on ArchLinux
and it caused this problem. Either removing `proofgeneral` or upgrading
`mmm-mode` to the latest version (0.5.1 as of 2015 Dec) resolves this issue.


Contributions
=============

Contributions are welcome!

If your contribution is a bug fix, create your topic branch from
`master`. If it is a new feature, check if there exists a
WIP(work-in-progress) branch (`vMAJOR.MINOR-wip`). If it does, use
that branch, otherwise use `master`.

Install [Cask](https://github.com/cask/cask) if you haven't already,
then:

 $ cd /path/to/lean/src/emacs
 $ cask

Run all tests with:

 $ make