1 files changed, 52 insertions, 0 deletions
diff --git a/lisp/ldg-exec.el b/lisp/ldg-exec.el
index bf3565b4..e9cefd20 100644
--- a/lisp/ldg-exec.el
+++ b/lisp/ldg-exec.el
@@ -1,3 +1,30 @@
+;;; ldg-exec.el --- Helper code for use with the "ledger" command-line tool
+
+;; Copyright (C) 2003-2013 John Wiegley (johnw AT gnu DOT org)
+
+;; This file is not part of GNU Emacs.
+
+;; This is free software; you can redistribute it and/or modify it under
+;; the terms of the GNU General Public License as published by the Free
+;; Software Foundation; either version 2, or (at your option) any later
+;; version.
+;;
+;; This is distributed in the hope that it will be useful, but WITHOUT
+;; ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+;; FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+;; for more details.
+;;
+;; You should have received a copy of the GNU General Public License
+;; along with GNU Emacs; see the file COPYING.  If not, write to the
+;; Free Software Foundation, Inc., 59 Temple Place - Suite 330, Boston,
+;; MA 02111-1307, USA.
+
+(defconst ledger-version-needed "3.0.0"
+  "The version of ledger executable needed for interactive features")
+
+(defvar ledger-works nil
+  "Flag showing whether the ledger binary can support ledger-mode interactive features")
+
 (defgroup ledger-exec nil
   "Interface to the Ledger command-line accounting program."
   :group 'ledger)
@@ -31,4 +58,29 @@
         (read (current-buffer))
       (kill-buffer (current-buffer)))))
 
+(defun ledger-version-greater-p (needed)
+  "verify the ledger binary is usable for ledger-mode"
+  (let ((buffer ledger-buf)
+        (version-strings '())
+	(version-number))
+    (with-temp-buffer
+      (ledger-exec-ledger buffer (current-buffer) "--version")
+      (goto-char (point-min))
+      (delete-horizontal-space)
+      (setq version-strings (split-string
+			     (buffer-substring-no-properties (point)
+							     (+ (point) 12))))
+      (if (and (string-match (regexp-quote "Ledger") (car version-strings))
+	       (or (string= needed (car (cdr version-strings)))
+		   (string< needed (car (cdr version-strings)))))
+	  t
+	  nil))))
+
+(defun ledger-check-version ()
+  (interactive)
+  (setq ledger-works (ledger-version-greater-p ledger-version-needed))
+  (if ledger-works
+      (message "Good Ledger Version")
+      (message "Bad Ledger Version")))
+
 (provide 'ldg-exec)