Add Scheme support

--- constants/constants.el.orig	2015-12-26 17:44:31.734520833 +0100
+++ constants/constants.el	2015-12-30 17:41:28.402871263 +0100
@@ -684,6 +684,33 @@
 
 (eval-when-compile (defvar ctable))
 
+(defun constants-is-lisp-like (mode)
+  (save-match-data
+    (string-match "\\(lisp\\|scheme\\)" (symbol-name mode))))
+
+(defun constants-is-set-like ()
+  (save-excursion
+    (condition-case nil
+        (save-match-data
+          (progn (up-list -1)
+                 (or (looking-at "(set[qf!]?\\>") (looking-at "(define\\>"))))
+      (error nil))))     ; return value nil means use default
+
+;;;###autoload
+(defun constants-lisp-like-function ()
+  "Check context for constants insertion."
+  (if (constants-is-set-like)
+      '(emacs-lisp-mode "%n %v%t; %d %u" "e" "(* %p %v)")
+    '(emacs-lisp-mode "(%n %v)%t; %d %u" "e" "(* %p %v)")))
+
+;;;###autoload
+(mapc (lambda (mode-hook)
+        (add-hook mode-hook
+                  (lambda ()
+                    (setq constants-language-function
+                          'constants-lisp-like-function))))
+      '(scheme-mode-hook emacs-lisp-mode-hook lisp-mode-hook))
+
 ;;;###autoload
 (defun constants-insert (&optional unit-system names)
   "Insert one or more natural constant definitions in source code.
@@ -826,8 +853,9 @@
             (funcall process-func ins))
         ;; Here comes the insertion stuff for source code editing modes.
         ;; First make sure we start a new line
-        (if (string-match
-             "\\S-" (buffer-substring (point-at-bol) (point-at-eol)))
+        (if (and (string-match
+                  "\\S-" (buffer-substring (point-at-bol) (point-at-eol)))
+                 (not (constants-is-lisp-like mode)))
             ;; non-empty line, insert after this line
             (progn 
               (end-of-line 1) 
@@ -841,13 +869,24 @@
           (if (string-match "\\(.*\\)%t\\(.*\\)" line)
               (let ((comment-column 42))
                 (insert (match-string 1 line))
-                (indent-to comment-column)
-                (insert (match-string 2 line)))
+                (if (and (constants-is-lisp-like mode)
+                         (or (constants-is-set-like)
+                             (null clist)))
+                    (save-excursion
+                      (progn
+                        (move-to-column comment-column t)
+                        (insert (match-string 2 line))
+                        ;; insert a newline such that paredit's M-) can mode
+                        ;; the closing parentheses to the next line.
+                        (newline-and-indent)))
+                  (progn
+                    (indent-to comment-column)
+                    (insert (match-string 2 line)))))
             (insert line)))
-        (if constants-indent-code
-            (newline-and-indent)
-          (newline))))))
-
+        (unless (and (constants-is-lisp-like mode) (null clist))
+          (if constants-indent-code
+              (newline-and-indent)
+            (newline)))))))
 ;;;###autoload
 (defun constants-get (&optional const message)
   "Return the value of CONST as defined in the constants package.
5-11-18 08:36:27 +0200'>2015-11-18</span></td><td><a href='/guix/commit/gnu/packages/wget.scm?id=49846012f098be181ca84d66233edb07fbc77d67'>Revert "gnu: wget: Update to 1.17."</a><span class='msg-avail'>...</span></td><td>Efraim Flashner</td></tr>
<tr><td><span title='2015-11-17 00:46:21 +0200'>2015-11-17</span></td><td><a href='/guix/commit/gnu/packages/wget.scm?id=4ca02340691624316330619fc6fec5a5e68e00b7'>gnu: wget: Update to 1.17.</a><span class='msg-avail'>...</span></td><td>Efraim Flashner</td></tr>
<tr><td><span title='2015-07-18 13:05:01 +0300'>2015-07-18</span></td><td><a href='/guix/commit/gnu/packages/wget.scm?id=e881752c39d455a249731a4e81e64d86f50afc34'>gnu packages: Clean up synopses and descriptions.</a><span class='msg-avail'>...</span></td><td>Alex Kost</td></tr>
<tr><td><span title='2015-07-05 17:09:42 +0200'>2015-07-05</span></td><td><a href='/guix/commit/gnu/packages/wget.scm?id=a7fd7b68a6727ea168ae69893a01d7731e9073cf'>gnu: Rename module gnutls to tls.</a><span class='msg-avail'>...</span></td><td>Andreas Enge</td></tr>
<tr><td><span title='2015-03-09 23:51:43 +0100'>2015-03-09</span></td><td><a href='/guix/commit/gnu/packages/wget.scm?id=1ae8237fc94d5f5a93ec7b5804d58ceda057f7e5'>gnu: wget: Update to 1.16.3.</a><span class='msg-avail'>...</span></td><td>Ludovic Courtès</td></tr>
<tr><td><span title='2015-03-01 22:22:43 +0100'>2015-03-01</span></td><td><a href='/guix/commit/gnu/packages/wget.scm?id=6b9540bcff0b57058aa30823b9815a9998fd544a'>gnu: wget: Update to 1.16.2.</a><span class='msg-avail'>...</span></td><td>Ludovic Courtès</td></tr>