Installation
============

To use `lean4-mode` in Emacs, add the following to your `init.el`:
```
;; You need to modify the following line
(setq load-path (cons "/path/to/lean4/lean4-mode" load-path))

(setq lean4-mode-required-packages '(dash dash-functional f flycheck s))

(require 'package)
(add-to-list 'package-archives '("melpa" . "http://melpa.org/packages/"))
(package-initialize)
(let ((need-to-refresh t))
  (dolist (p lean4-mode-required-packages)
    (when (not (package-installed-p p))
      (when need-to-refresh
        (package-refresh-contents)
        (setq need-to-refresh nil))
      (package-install p))))

(require 'lean4-mode)
```

Trying It Out
=============

If things are working correctly, you should see the word ``Lean 4`` in the
Emacs mode line when you open a file with extension `.lean`. If you type
```lean
#check id
```
the word ``#check`` will be underlined, and hovering over it will show
you the type of ``id``. The mode line will show ``FlyC:0/1``, indicating
that there are no errors and one piece of information displayed.

Key Bindings and Commands
=========================

| Key                | Function                                                                        |
|--------------------|---------------------------------------------------------------------------------|
| <kbd>C-c C-k</kbd> | shows the keystroke needed to input the symbol under the cursor                 |
| <kbd>C-c C-x</kbd> | execute lean in stand-alone mode (`lean-std-exe`)                               |
| <kbd>C-c C-n</kbd> | toggle showing next error in dedicated buffer (`lean-toggle-next-error`)        |
| <kbd>C-c ! n</kbd> | flycheck: go to next error                                                      |
| <kbd>C-c ! p</kbd> | flycheck: go to previous error                                                  |
| <kbd>C-c ! l</kbd> | flycheck: show list of errors                                                   |

In the default configuration, the Flycheck annotation `FlyC:n/n` indicates the
number of errors / responses from Lean; clicking on `FlyC` opens the Flycheck menu.