From 936c933fd8b7bb71b8a7fd845f27cf50b3fa0402 Mon Sep 17 00:00:00 2001
From: Marijn Haverbeke <marijnh@gmail.com>
Date: Mon, 16 Jan 2012 12:44:24 +0100
Subject: [PATCH] Move emacs mode into tree

---
 doc/tutorial/setup.md      |   4 +-
 src/etc/emacs/Makefile     |  14 ++
 src/etc/emacs/README.md    |  27 ++++
 src/etc/emacs/cm-mode.el   | 186 ++++++++++++++++++++++++
 src/etc/emacs/rust-mode.el | 283 +++++++++++++++++++++++++++++++++++++
 5 files changed, 512 insertions(+), 2 deletions(-)
 create mode 100644 src/etc/emacs/Makefile
 create mode 100644 src/etc/emacs/README.md
 create mode 100644 src/etc/emacs/cm-mode.el
 create mode 100644 src/etc/emacs/rust-mode.el

diff --git a/doc/tutorial/setup.md b/doc/tutorial/setup.md
index a1a28d903a0..f85052961a0 100644
--- a/doc/tutorial/setup.md
+++ b/doc/tutorial/setup.md
@@ -47,8 +47,8 @@ detail [later on](mod.html).
 ## Editing Rust code
 
 There are Vim highlighting and indentation scrips in the Rust source
-distribution under `src/etc/vim/`. An Emacs mode can be found at
-[https://github.com/marijnh/rust-mode][rust-mode].
+distribution under `src/etc/vim/`, and an emacs mode under
+`src/etc/emacs/`.
 
 [rust-mode]: https://github.com/marijnh/rust-mode
 
diff --git a/src/etc/emacs/Makefile b/src/etc/emacs/Makefile
new file mode 100644
index 00000000000..c79e7a9719b
--- /dev/null
+++ b/src/etc/emacs/Makefile
@@ -0,0 +1,14 @@
+E=@echo
+TEMP=temp.el
+
+EMACS ?= emacs
+
+all: $(TEMP)
+	$(EMACS) -batch -q -no-site-file -l ./$(TEMP) -f rustmode-compile
+	rm -f $(TEMP)
+$(TEMP):
+	$(E) '(setq load-path (cons "." load-path))' >> $(TEMP)
+	$(E) '(defun rustmode-compile () (mapcar (lambda (x) (byte-compile-file x))' >> $(TEMP)
+	$(E) ' (list "cm-mode.el" "rust-mode.el")))' >> $(TEMP)
+clean:
+	rm -f *.elc $(TEMP)
diff --git a/src/etc/emacs/README.md b/src/etc/emacs/README.md
new file mode 100644
index 00000000000..7bfeebeef6b
--- /dev/null
+++ b/src/etc/emacs/README.md
@@ -0,0 +1,27 @@
+rust-mode: A major emacs mode for editing Rust source code
+==========================================================
+
+`rust-mode` makes editing [Rust](http://rust-lang.org) code with emacs
+enjoyable.
+
+To install, check out this repository and add this to your .emacs
+file:
+
+    (add-to-list 'load-path "/path/to/rust-mode/")
+    (require 'rust-mode)
+
+Make sure you byte-compile the .el files first, or the mode will be
+painfully slow. There is an included `Makefile` which will do it for
+you, so in the simplest case you can just run `make` and everything
+should Just Work.
+
+If for some reason that doesn't work, you can byte compile manually,
+by pasting this in your `*scratch*` buffer, moving the cursor below
+it, and pressing `C-j`:
+
+    (progn
+      (byte-compile-file "/path/to/rust-mode/cm-mode.el" t)
+      (byte-compile-file "/path/to/rust-mode/rust-mode.el" t))
+
+Rust mode will automatically be associated with .rs and .rc files. To
+enable it explicitly, do `M-x rust-mode`.
diff --git a/src/etc/emacs/cm-mode.el b/src/etc/emacs/cm-mode.el
new file mode 100644
index 00000000000..469bded047a
--- /dev/null
+++ b/src/etc/emacs/cm-mode.el
@@ -0,0 +1,186 @@
+;; Wrapper for CodeMirror-style emacs modes. Highlighting is done by
+;; running a stateful parser (with first-class state object) over the
+;; buffer, line by line, using the output to add 'face properties, and
+;; storing the parser state at the end of each line. Indentation is
+;; done based on the parser state at the start of the line.
+
+(eval-when-compile (require 'cl))
+
+;; Mode data structure
+
+(defun make-cm-mode (token &optional start-state copy-state
+                           compare-state indent)
+  (vector token
+          (or start-state (lambda () 'null))
+          (or copy-state 'cm-default-copy-state)
+          (or compare-state 'eq)
+          indent))
+(defmacro cm-mode-token (x) `(aref ,x 0))
+(defmacro cm-mode-start-state (x) `(aref ,x 1))
+(defmacro cm-mode-copy-state (x) `(aref ,x 2))
+(defmacro cm-mode-compare-state (x) `(aref ,x 3))
+(defmacro cm-mode-indent (x) `(aref ,x 4))
+
+(defvar cm-cur-mode nil)
+(defvar cm-worklist nil)
+
+(defun cm-default-copy-state (state)
+  (if (consp state) (copy-sequence state) state))
+
+(defun cm-clear-work-items (from to)
+  (let ((prev-cons nil)
+        (rem cm-worklist))
+    (while rem
+      (let ((pos (marker-position (car rem))))
+        (cond ((or (< pos from) (> pos to)) (setf prev-cons rem))
+              (prev-cons (setf (cdr prev-cons) (cdr rem)))
+              (t (setf cm-worklist (cdr rem))))
+        (setf rem (cdr rem))))))
+
+(defun cm-min-worklist-item ()
+  (let ((rest cm-worklist) (min most-positive-fixnum))
+    (while rest
+      (let ((pos (marker-position (car rest))))
+        (when (< pos min) (setf min pos)))
+      (setf rest (cdr rest)))
+    min))
+
+;; Indentation
+
+(defun cm-indent ()
+  (let (indent-pos)
+    (save-excursion
+      (beginning-of-line)
+      (let* ((buf (current-buffer))
+             (state (cm-preserve-state buf 'cm-state-for-point))
+             (old-indent (current-indentation)))
+        (back-to-indentation)
+        (setf indent-pos (point))
+        (let ((new-indent (funcall (cm-mode-indent cm-cur-mode) state)))
+          (unless (= old-indent new-indent)
+            (indent-line-to new-indent)
+            (setf indent-pos (point))
+            (beginning-of-line)
+            (cm-preserve-state buf
+             (lambda ()
+               (cm-highlight-line state)
+               (when (< (point) (point-max))
+                 (put-text-property (point) (+ (point) 1) 'cm-parse-state state))))))))
+    (when (< (point) indent-pos)
+      (goto-char indent-pos))))
+
+(defun cm-backtrack-to-state ()
+  (let ((backtracked 0)
+        (min-indent most-positive-fixnum)
+        min-indented)
+    (loop
+     (when (= (point) (point-min))
+       (return (funcall (cm-mode-start-state cm-cur-mode))))
+     (let ((st (get-text-property (- (point) 1) 'cm-parse-state)))
+       (when (and st (save-excursion
+                       (backward-char)
+                       (beginning-of-line)
+                       (not (looking-at "[	 ]*$"))))
+         (return (funcall (cm-mode-copy-state cm-cur-mode) st))))
+     (let ((i (current-indentation)))
+       (when (< i min-indent)
+         (setf min-indent i min-indented (point))))
+     (when (> (incf backtracked) 30)
+       (goto-char min-indented)
+       (return (funcall (cm-mode-start-state cm-cur-mode))))
+     (forward-line -1))))
+
+(defun cm-state-for-point ()
+  (let ((pos (point))
+        (state (cm-backtrack-to-state)))
+    (while (< (point) pos)
+      (cm-highlight-line state)
+      (put-text-property (point) (+ (point) 1) 'cm-parse-state
+                         (funcall (cm-mode-copy-state cm-cur-mode) state))
+      (forward-char))
+    state))
+
+;; Highlighting
+
+(defun cm-highlight-line (state)
+  (let ((eol (point-at-eol)))
+    (remove-text-properties (point) eol '(face))
+    (loop
+     (let ((p (point)))
+       (when (= p eol) (return))
+       (let ((style (funcall (cm-mode-token cm-cur-mode) state)))
+         (when (= p (point)) (print (point)) (error "Nothing consumed."))
+         (when (> p eol) (error "Parser moved past EOL"))
+         (when style
+           (put-text-property p (point) 'face style)))))))
+
+(defun cm-find-state-before-point ()
+  (loop
+   (beginning-of-line)
+   (when (= (point) 1)
+     (return (funcall (cm-mode-start-state cm-cur-mode))))
+   (let ((cur (get-text-property (- (point) 1) 'cm-parse-state)))
+     (when cur (return (funcall (cm-mode-copy-state cm-cur-mode) cur))))
+   (backward-char)))
+
+(defun cm-schedule-work (delay)
+  (run-with-idle-timer delay nil 'cm-preserve-state (current-buffer) 'cm-do-some-work))
+
+(defun cm-preserve-state (buffer f &rest args)
+  (with-current-buffer buffer
+    (let ((modified (buffer-modified-p))
+          (buffer-undo-list t)
+          (inhibit-read-only t)
+          (inhibit-point-motion-hooks t)
+          (inhibit-modification-hooks t))
+      (unwind-protect (apply f args)
+        (unless modified
+          (restore-buffer-modified-p nil))))))
+
+(defun cm-do-some-work-inner ()
+  (let ((end-time (time-add (current-time) (list 0 0 500)))
+        (quitting nil))
+    (while (and (not quitting) cm-worklist)
+      (goto-char (cm-min-worklist-item))
+      (let ((state (cm-find-state-before-point))
+            (startpos (point))
+            (timer-idle-list nil))
+        (loop
+         (cm-highlight-line state)
+         (when (= (point) (point-max)) (return))
+         (let ((old (get-text-property (point) 'cm-parse-state)))
+           (when (and old (funcall (cm-mode-compare-state cm-cur-mode) state old))
+             (return))
+           (put-text-property (point) (+ (point) 1) 'cm-parse-state
+                              (funcall (cm-mode-copy-state cm-cur-mode) state)))
+         (when (or (let ((timer-idle-list nil)) (input-pending-p))
+                   (time-less-p end-time (current-time)))
+           (setf quitting t) (return))
+         (forward-char))
+        (cm-clear-work-items startpos (point)))
+      (when quitting
+        (push (copy-marker (+ (point) 1)) cm-worklist)
+        (cm-schedule-work 0.05)))))
+
+(defun cm-do-some-work ()
+  (save-excursion 
+    (condition-case cnd (cm-do-some-work-inner)
+      (error (print cnd) (error cnd)))))
+
+(defun cm-after-change-function (from to oldlen)
+  (cm-preserve-state (current-buffer) 'remove-text-properties from to '(cm-parse-state))
+  (push (copy-marker from) cm-worklist)
+  (cm-schedule-work 0.2))
+
+;; Entry function
+
+(defun cm-mode (mode)
+  (set (make-local-variable 'cm-cur-mode) mode)
+  (set (make-local-variable 'cm-worklist) (list (copy-marker 1)))
+  (when (cm-mode-indent mode)
+    (set (make-local-variable 'indent-line-function) 'cm-indent))
+  (add-hook 'after-change-functions 'cm-after-change-function t t)
+  (add-hook 'after-revert-hook (lambda () (cm-after-change-function 1 (point-max) nil)) t t)
+  (cm-schedule-work 0.05))
+
+(provide 'cm-mode)
diff --git a/src/etc/emacs/rust-mode.el b/src/etc/emacs/rust-mode.el
new file mode 100644
index 00000000000..e4f0ee6c62f
--- /dev/null
+++ b/src/etc/emacs/rust-mode.el
@@ -0,0 +1,283 @@
+(require 'cm-mode)
+(require 'cc-mode)
+
+(defun rust-electric-brace (arg)
+  (interactive "*P")
+  (self-insert-command (prefix-numeric-value arg))
+  (when (and c-electric-flag
+             (not (member (get-text-property (point) 'face)
+                          '(font-lock-comment-face font-lock-string-face))))
+    (cm-indent)))
+
+(defvar rust-indent-unit 4)
+(defvar rust-syntax-table (let ((table (make-syntax-table)))
+                            (c-populate-syntax-table table)
+                            table))
+
+(add-to-list 'auto-mode-alist '("\\.rs$" . rust-mode))
+(add-to-list 'auto-mode-alist '("\\.rc$" . rust-mode))
+
+(defun make-rust-state ()
+  (vector 'rust-token-base
+          (list (vector 'top (- rust-indent-unit) nil nil nil))
+          0
+          nil))
+(defmacro rust-state-tokenize (x) `(aref ,x 0))
+(defmacro rust-state-context (x) `(aref ,x 1))
+(defmacro rust-state-indent (x) `(aref ,x 2))
+(defmacro rust-state-last-token (x) `(aref ,x 3))
+
+(defmacro rust-context-type (x) `(aref ,x 0))
+(defmacro rust-context-indent (x) `(aref ,x 1))
+(defmacro rust-context-column (x) `(aref ,x 2))
+(defmacro rust-context-align (x) `(aref ,x 3))
+(defmacro rust-context-info (x) `(aref ,x 4))
+
+(defun rust-push-context (st type &optional align-column auto-align)
+  (let ((ctx (vector type (rust-state-indent st) align-column
+                     (if align-column (if auto-align t 'unset) nil) nil)))
+    (push ctx (rust-state-context st))
+    ctx))
+(defun rust-pop-context (st)
+  (let ((old (pop (rust-state-context st))))
+    (setf (rust-state-indent st) (rust-context-indent old))
+    old))
+(defun rust-dup-context (st)
+  (let* ((list (rust-state-context st))
+         (dup (copy-sequence (car list))))
+    (setf (rust-state-context st) (cons dup (cdr list)))
+    dup))
+
+(defvar rust-operator-chars "-+/%=<>!*&|@~^")
+(defvar rust-punc-chars "()[].,{}:;")
+(defvar rust-value-keywords
+  (let ((table (make-hash-table :test 'equal)))
+    (dolist (word '("mod" "type" "resource" "fn" "tag" "iface" "impl"))
+      (puthash word 'def table))
+    (dolist (word '("if" "else" "while" "do" "for" "break" "cont" "ret" "be" "fail" "const"
+                    "check" "assert" "claim" "prove" "native" "import" "export" "let" "log"
+                    "use" "pure" "unsafe"))
+      (puthash word t table))
+    (puthash "alt" 'alt table)
+    (dolist (word '("true" "false")) (puthash word 'atom table))
+    table))
+;; FIXME type-context keywords
+
+(defvar rust-tcat nil "Kludge for multiple returns without consing")
+
+(defmacro rust-eat-re (re)
+  `(when (looking-at ,re) (goto-char (match-end 0)) t))
+
+(defvar rust-char-table
+  (let ((table (make-char-table 'syntax-table)))
+    (macrolet ((def (range &rest body)
+                    `(let ((--b (lambda (st) ,@body)))
+                       ,@(mapcar (lambda (elt)
+	                           (if (consp elt)
+                                       `(loop for ch from ,(car elt) to ,(cdr elt) collect
+                                              (set-char-table-range table ch --b))
+                                     `(set-char-table-range table ',elt --b)))
+                                 (if (consp range) range (list range))))))
+      (def t (forward-char) nil)
+      (def (32 ?\t) (skip-chars-forward " \t") nil)
+      (def ?\" (forward-char)
+           (rust-push-context st 'string (current-column) t)
+           (setf (rust-state-tokenize st) 'rust-token-string)
+           (rust-token-string st))
+      (def ?\' (forward-char)
+           (setf rust-tcat 'atom)
+           (let ((is-escape (eq (char-after) ?\\))
+                 (start (point)))
+             (if (not (rust-eat-until-unescaped ?\'))
+                 'font-lock-warning-face
+               (if (or is-escape (= (point) (+ start 2)))
+                   'font-lock-string-face 'font-lock-warning-face))))
+      (def ?/ (forward-char)
+           (case (char-after)
+             (?/ (end-of-line) 'font-lock-comment-face)
+             (?* (forward-char)
+                 (rust-push-context st 'comment)
+                 (setf (rust-state-tokenize st) 'rust-token-comment)
+                 (rust-token-comment st))
+             (t (skip-chars-forward rust-operator-chars) (setf rust-tcat 'op) nil)))
+      (def ?# (forward-char)
+           (cond ((eq (char-after) ?\[) (forward-char) (setf rust-tcat 'open-attr))
+                 ((rust-eat-re "[a-z_]+") (setf rust-tcat 'macro)))
+           'font-lock-preprocessor-face)
+      (def ((?a . ?z) (?A . ?Z) ?_)
+           (rust-eat-re "[a-zA-Z_][a-zA-Z0-9_]*")
+           (setf rust-tcat 'ident)
+           (if (and (eq (char-after) ?:) (eq (char-after (+ (point) 1)) ?:)
+                    (not (eq (char-after (+ (point) 2)) ?:)))
+               (progn (forward-char 2) 'font-lock-builtin-face)
+             (match-string 0)))
+      (def ((?0 . ?9))
+           (rust-eat-re "0x[0-9a-fA-F_]+\\|0b[01_]+\\|[0-9_]+\\(\\.[0-9_]+\\)?\\(e[+\\-]?[0-9_]+\\)?")
+           (setf rust-tcat 'atom)
+           (rust-eat-re "[iuf][0-9_]*")
+           'font-lock-constant-face)
+      (def ?. (forward-char)
+           (cond ((rust-eat-re "[0-9]+\\(e[+\\-]?[0-9]+\\)?")
+                  (setf rust-tcat 'atom)
+                  (rust-eat-re "f[0-9]+")
+                  'font-lock-constant-face)
+                 (t (setf rust-tcat (char-before)) nil)))
+      (def (?\( ?\) ?\[ ?\] ?\{ ?\} ?: ?\; ?,)
+           (forward-char)
+           (setf rust-tcat (char-before)) nil)
+      (def ?|
+           (skip-chars-forward rust-operator-chars)
+           (setf rust-tcat 'pipe) nil)
+      (def (?+ ?- ?% ?= ?< ?> ?! ?* ?& ?@ ?~)
+           (skip-chars-forward rust-operator-chars)
+           (setf rust-tcat 'op) nil)
+      table)))
+
+(defun rust-token-base (st)
+  (funcall (char-table-range rust-char-table (char-after)) st))
+
+(defun rust-eat-until-unescaped (ch)
+  (let (escaped)
+    (loop
+     (let ((cur (char-after)))
+       (when (or (eq cur ?\n) (not cur)) (return nil))
+       (forward-char)
+       (when (and (eq cur ch) (not escaped)) (return t))
+       (setf escaped (and (not escaped) (eq cur ?\\)))))))
+
+(defun rust-token-string (st)
+  (setf rust-tcat 'atom)
+  (cond ((rust-eat-until-unescaped ?\")
+         (setf (rust-state-tokenize st) 'rust-token-base)
+         (rust-pop-context st))
+        (t (let ((align (eq (char-before) ?\\)))
+             (unless (eq align (rust-context-align (car (rust-state-context st))))
+               (setf (rust-context-align (rust-dup-context st)) align)))))
+  'font-lock-string-face)
+
+(defun rust-token-comment (st)
+  (let ((eol (point-at-eol)))
+    (loop
+     (unless (re-search-forward "\\(/\\*\\)\\|\\(\\*/\\)" eol t)
+       (goto-char eol)
+       (return))
+     (if (match-beginning 1)
+         (push (car (rust-state-context st)) (rust-state-context st))
+       (rust-pop-context st)
+       (unless (eq (rust-context-type (car (rust-state-context st))) 'comment)
+         (setf (rust-state-tokenize st) 'rust-token-base)
+         (return))))
+    'font-lock-comment-face))
+
+(defun rust-next-block-info (st)
+  (dolist (cx (rust-state-context st))
+    (when (eq (rust-context-type cx) ?\}) (return (rust-context-info cx)))))
+
+(defun rust-token (st)
+  (let ((cx (car (rust-state-context st))))
+    (when (bolp)
+      (setf (rust-state-indent st) (current-indentation))
+      (when (eq (rust-context-align cx) 'unset)
+        (setf (rust-context-align cx) nil)))
+    (setf rust-tcat nil)
+    (let* ((tok (funcall (rust-state-tokenize st) st))
+           (tok-id (or tok rust-tcat))
+           (cur-cx (rust-context-type cx))
+           (cx-info (rust-context-info cx)))
+      (when (stringp tok)
+        (setf tok-id (gethash tok rust-value-keywords nil))
+        (setf tok (cond ((eq tok-id 'atom) 'font-lock-constant-face)
+                        (tok-id 'font-lock-keyword-face)
+                        ((equal (rust-state-last-token st) 'def) 'font-lock-function-name-face)
+                        (t nil))))
+      (when rust-tcat
+        (when (eq (rust-context-align cx) 'unset)
+          (setf (rust-context-align cx) t))
+        (when (eq cx-info 'alt-1)
+          (setf cx (rust-dup-context st))
+          (setf (rust-context-info cx) 'alt-2))
+        (when (and (eq rust-tcat 'pipe) (eq (rust-state-last-token st) ?{))
+          (setf cx (rust-dup-context st))
+          (setf (rust-context-info cx) 'block))
+        (case rust-tcat
+          ((?\; ?,) (when (eq cur-cx 'statement) (rust-pop-context st)))
+          (?\{
+           (when (and (eq cur-cx 'statement) (not (member cx-info '(alt-1 alt-2))))
+             (rust-pop-context st))
+           (when (eq cx-info 'alt-2)
+             (setf cx (rust-dup-context st))
+             (setf (rust-context-info cx) nil))
+           (let ((next-info (rust-next-block-info st))
+                 (newcx (rust-push-context st ?\} (current-column))))
+             (cond ((eq cx-info 'alt-2) (setf (rust-context-info newcx) 'alt-outer))
+                   ((eq next-info 'alt-outer) (setf (rust-context-info newcx) 'alt-inner)))))
+          ((?\[ open-attr)
+           (let ((newcx (rust-push-context st ?\] (current-column))))
+             (when (eq rust-tcat 'open-attr)
+               (setf (rust-context-info newcx) 'attr))))
+          (?\( (rust-push-context st ?\) (current-column))
+               (when (eq (rust-context-info cx) 'attr)
+                 (setf (rust-context-info (car (rust-state-context st))) 'attr)))
+          (?\} (when (eq cur-cx 'statement) (rust-pop-context st))
+               (when (eq (rust-context-type (car (rust-state-context st))) ?})
+                 (rust-pop-context st))
+               (setf cx (car (rust-state-context st)))
+               (when (and (eq (rust-context-type cx) 'statement)
+                          (not (eq (rust-context-info cx) 'alt-2)))
+                 (rust-pop-context st)))
+          (t (cond ((eq cur-cx rust-tcat)
+                    (when (eq (rust-context-info (rust-pop-context st)) 'attr)
+                      (setf tok 'font-lock-preprocessor-face)
+                      (when (eq (rust-context-type (car (rust-state-context st))) 'statement)
+                        (rust-pop-context st))))
+                   ((or (and (eq cur-cx ?\}) (not (eq (rust-context-info cx) 'alt-outer)))
+                        (eq cur-cx 'top))
+                    (rust-push-context st 'statement)))))
+        (setf (rust-state-last-token st) tok-id))
+      (setf cx (car (rust-state-context st)))
+      (when (and (eq tok-id 'alt) (eq (rust-context-type cx) 'statement))
+        (setf (rust-context-info cx) 'alt-1))
+      (when (and (eq (rust-state-last-token st) 'pipe)
+                 (eq (rust-next-block-info st) 'block) (eolp))
+        (when (eq (rust-context-type cx) 'statement) (rust-pop-context st))
+        (setf cx (rust-dup-context st)
+              (rust-context-info cx) nil
+              (rust-context-align cx) nil))
+      (if (eq (rust-context-info cx) 'attr)
+          'font-lock-preprocessor-face
+        tok))))
+
+(defun rust-indent (st)
+  (let ((cx (car (rust-state-context st)))
+        (parent (cadr (rust-state-context st))))
+    (when (and (eq (rust-context-type cx) 'statement)
+               (or (eq (char-after) ?\}) (looking-at "with \\|{[ 	]*$")))
+      (setf cx parent parent (caddr (rust-state-context st))))
+    (let* ((tp (rust-context-type cx))
+           (closing (eq tp (char-after)))
+           (unit (if (member (rust-context-info cx) '(alt-inner alt-outer))
+                     (/ rust-indent-unit 2) rust-indent-unit))
+           (base (if (and (eq tp 'statement) parent (rust-context-align parent))
+                     (rust-context-column parent) (rust-context-indent cx))))
+      (cond ((eq tp 'comment) base)
+            ((eq tp 'string) (if (rust-context-align cx) (rust-context-column cx) 0))
+            ((eq tp 'statement) (+ base (if (eq (char-after) ?\}) 0 unit)))
+            ((eq (rust-context-align cx) t) (+ (rust-context-column cx) (if closing -1 0)))
+            (t (+ base (if closing 0 unit)))))))
+
+(define-derived-mode rust-mode fundamental-mode "Rust"
+  "Major mode for editing Rust source files."
+  (set-syntax-table rust-syntax-table)
+  (setq major-mode 'rust-mode mode-name "Rust")
+  (run-hooks 'rust-mode-hook)
+  (set (make-local-variable 'indent-tabs-mode) nil)
+  (let ((par "[ 	]*\\(//+\\|\\**\\)[ 	]*$"))
+    (set (make-local-variable 'paragraph-start) par)
+    (set (make-local-variable 'paragraph-separate) par))
+  (set (make-local-variable 'comment-start) "//")
+  (cm-mode (make-cm-mode 'rust-token 'make-rust-state 'copy-sequence 'equal 'rust-indent)))
+
+(define-key rust-mode-map "}" 'rust-electric-brace)
+(define-key rust-mode-map "{" 'rust-electric-brace)
+
+(provide 'rust-mode)