* mu-stats.scm: add some simple examples on getting message statistics

toys/muile/mu-stats.scm

@@ -0,0 +1,43 @@
+;;
+;; Copyright (C) 2011 Dirk-Jan C. Binnema <djcb@djcbsoftware.nl>
+;;
+;; This program 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 3, or (at your option) any
+;; later version.
+;;
+;; This program 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 this program; if not, write to the Free Software Foundation,
+;; Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
+;;
+;;
+
+;; some guile/scheme functions to get various statistics of my mu
+;; message store.
+
+;; note, this is a rather inefficient way to calculate the number; for
+;; demonstration purposes only
+(define (mu:stats:count EXPR)
+  "Count the total number of messages. If the optional EXPR is
+provided, only count the messages that match it.\n"
+  (mu:store:foreach (lambda(msg) #f) EXPR))
+
+
+(define (mu:stats:average-size EXPR)
+  "Count the total number of messages. If the optional EXPR is
+provided, only count the messages that match it.\n"
+  (let* ((sum 0)
+	  (n (mu:store:foreach
+	       (lambda(msg) (set! sum (+ sum (mu:msg:size msg)))) EXPR)))
+    (if (= n 0) 0 (exact->inexact (/ sum n)))))
+
+
+
+
+
+