From 04cd02784b5d4339acbf0d5c74a3fd5451daded7 Mon Sep 17 00:00:00 2001
From: nex3 <nex3@7063305b-7217-0410-af8c-cdc13e5119b9>
Date: Thu, 8 Mar 2007 06:50:46 +0000
Subject: [PATCH] Added a handy backspace binding to the haml-mode.el.

git-svn-id: svn://hamptoncatlin.com/haml/trunk@401 7063305b-7217-0410-af8c-cdc13e5119b9
---
 extra/haml-mode.el | 26 +++++++++++++++++++++++++-
 1 file changed, 25 insertions(+), 1 deletion(-)

diff --git a/extra/haml-mode.el b/extra/haml-mode.el
index eebc7c5d..acc85118 100644
--- a/extra/haml-mode.el
+++ b/extra/haml-mode.el
@@ -25,6 +25,11 @@
   :type 'integer
   :group 'haml)
 
+(defcustom haml-backspace-function 'backward-delete-char-untabify
+  "*Function called by `haml-electric-backspace' when deleting backwards."
+  :type 'function
+  :group 'haml)
+
 ;; Helper Functions
 
 (defun string-* (str i)
@@ -42,7 +47,7 @@
 (defconst haml-blank-line-re "^[ \t]*$"
   "Regexp matching a line containing only whitespace.")
 
-(defconst haml-tag-re (hre "[%\\.#][^ \t]*\\({.*}\\)?\\(\\[.*\\]\\).?[ \t]*$")
+(defconst haml-tag-re (hre "[%\\.#][^ \t]*\\({.*}\\)?\\(\\[.*\\]\\)?.?[ \t]*$")
   "Regexp matching a Haml tag.")
 
 (defconst haml-block-re (hre "[-=].*do[ \t]*\\(|.*|[ \t]*\\)?$")
@@ -70,6 +75,9 @@
 (if haml-mode-map
     nil
   (setq haml-mode-map (make-sparse-keymap))
+  (define-key haml-mode-map [backspace] 'haml-electric-backspace)
+  (define-key haml-mode-map "\C-?" 'haml-electric-backspace)
+  (define-key haml-mode-map "\C-a" 'haml-electric-backspace)
   (define-key haml-mode-map "\C-j" 'newline-and-indent))
 
 ;(defvar haml-mode-syntax-table nil
@@ -129,6 +137,22 @@ back-dent the line by `haml-indent-offset' spaces.  On reaching column
       (if (< (current-column) (current-indentation))
           (forward-to-indentation 0))))
 
+(defun haml-electric-backspace (arg)
+  "Delete characters or back-dent the current line.
+If invoked following only whitespace on a line, will back-dent to the
+immediately previous multiple of `haml-indent-offset' spaces."
+  (interactive "*p")
+  (if (or (/= (current-indentation) (current-column)) (bolp))
+      (funcall haml-backspace-function arg)
+    (let ((ci (current-column)))
+      (beginning-of-line)
+      (delete-horizontal-space)
+      (indent-to (* (/ (- ci (* arg haml-indent-offset))
+                       haml-indent-offset)
+                    haml-indent-offset)))))
+
+;; Setup/Activation
+
 (defun haml-mode-version ()
   "Diplay version of `haml-mode'."
   (interactive)