From 44a26cd1075f39f12b1a0a248147a52c57d7686b Mon Sep 17 00:00:00 2001
From: Nathan Weizenbaum <nex342@gmail.com>
Date: Tue, 24 Aug 2010 10:50:06 -0700
Subject: [PATCH] Make the js-mode indentation more customizable.

In particular, allow the user to customize how much additional indentation is
used for expressions within braces of various types. Also better document
js--proper-indentation.
---
 lisp/ChangeLog       |    6 +++++
 lisp/progmodes/js.el |   51 ++++++++++++++++++++++++++++++++++++++-----------
 2 files changed, 45 insertions(+), 12 deletions(-)

diff --git a/lisp/ChangeLog b/lisp/ChangeLog
index bb36d60..1bad604 100644
--- a/lisp/ChangeLog
+++ b/lisp/ChangeLog
@@ -1,3 +1,9 @@
+2010-08-24  Nathan Weizenbaum  <nweiz@cressida.sea.corp.google.com>
+
+	* progmodes/js.el: Make indentation more customizable by adding
+	variables `js-paren-indent-offset', `js-square-indent-offset', and
+	`js-curly-indent-offset'.
+
 2010-08-23  Michael Albinus  <michael.albinus@gmx.de>
 
 	* net/dbus.el: Accept UNIX domain sockets as bus address.
diff --git a/lisp/progmodes/js.el b/lisp/progmodes/js.el
index d6feca4..9d9dda7 100644
--- a/lisp/progmodes/js.el
+++ b/lisp/progmodes/js.el
@@ -436,6 +436,24 @@ The value must be no less than minus `js-indent-level'."
   :type 'integer
   :group 'js)
 
+(defcustom js-paren-indent-offset 0
+  "Number of additional spaces used for indentation of expressions within parentheses.
+The value must be no less than minus `js-indent-level'."
+  :type 'integer
+  :group 'js)
+
+(defcustom js-square-indent-offset 0
+  "Number of additional spaces used for indentation of expressions within square braces.
+The value must be no less than minus `js-indent-level'."
+  :type 'integer
+  :group 'js)
+
+(defcustom js-curly-indent-offset 0
+  "Number of additional spaces used for indentation of expressions within curly braces.
+The value must be no less than minus `js-indent-level'."
+  :type 'integer
+  :group 'js)
+
 (defcustom js-auto-indent-flag t
   "Whether to automatically indent when typing punctuation characters.
 If non-nil, the characters {}();,: also indent the current line
@@ -1762,21 +1780,24 @@ nil."
   "Return the proper indentation for the current line."
   (save-excursion
     (back-to-indentation)
-    (cond ((nth 4 parse-status)
+    (cond ((nth 4 parse-status) ; inside comment
            (js--get-c-offset 'c (nth 8 parse-status)))
           ((nth 8 parse-status) 0) ; inside string
-          ((js--ctrl-statement-indentation))
-          ((eq (char-after) ?#) 0)
-          ((save-excursion (js--beginning-of-macro)) 4)
-          ((nth 1 parse-status)
-           (let ((same-indent-p (looking-at
+          ((js--ctrl-statement-indentation)) ; inside braceless control structure
+          ((eq (char-after) ?#) 0) ; cpp directive
+          ((save-excursion (js--beginning-of-macro)) 4) ; cpp directive continuation
+          ((nth 1 parse-status) ; in parens or brackets
+           (let (;; A single closing paren/bracket should be indented at the
+                 ;; same level as the opening statement. Same goes for "case"
+                 ;; and "default".
+                 (same-indent-p (looking-at
                                  "[]})]\\|\\_<case\\_>\\|\\_<default\\_>"))
                  (continued-expr-p (js--continued-expression-p)))
-             (goto-char (nth 1 parse-status))
+             (goto-char (nth 1 parse-status)) ; go to the opening char
              (if (looking-at "[({[]\\s-*\\(/[/*]\\|$\\)")
-                 (progn
+                 (progn ; nothing following the opening paren/bracket
                    (skip-syntax-backward " ")
-		   (when (eq (char-before) ?\)) (backward-list))
+                   (when (eq (char-before) ?\)) (backward-list))
                    (back-to-indentation)
                    (cond (same-indent-p
                           (current-column))
@@ -1784,15 +1805,21 @@ nil."
                           (+ (current-column) (* 2 js-indent-level)
                              js-expr-indent-offset))
                          (t
-                          (+ (current-column) js-indent-level))))
+                          (+ (current-column) js-indent-level
+                             (case (char-after (nth 1 parse-status))
+                               (?\( js-paren-indent-offset)
+                               (?\[ js-square-indent-offset)
+                               (?\{ js-curly-indent-offset))))))
+               ;; If there is something following the opening paren/bracket,
+               ;; everything else should be indented at the same level as that.
                (unless same-indent-p
                  (forward-char)
                  (skip-chars-forward " \t"))
                (current-column))))
 
-          ((js--continued-expression-p)
+          ((js--continued-expression-p) ; in a toplevel expression
            (+ js-indent-level js-expr-indent-offset))
-          (t 0))))
+          (t 0)))) ; at toplevel, outside any expressions
 
 (defun js-indent-line ()
   "Indent the current line as JavaScript."
-- 
1.7.1