Use month data type for joined key.

member-file.scm

@@ -30,6 +30,7 @@
  (
   *member-file-context*
   *member-file-check-syntax*
+  *member-default-joined*
   load-member-file
   member-file-tests!
   )
@@ -63,6 +64,8 @@
  ;;  'quiet - ignore
  (define *member-file-check-syntax* (make-parameter 'error))
 
+ (define *member-default-joined* (make-parameter (make-month 2015 1)))
+
  ;; Derived keys
  (define start/stop-keys-keys
    (map
@@ -233,19 +236,29 @@
 		     m)
 		 (cdr ks))))))
 
+ ;; Converts given key to month if it is a string. Leaves untouched
+ ;; otherwise.
+ (define (convert-member-key:month m k)
+   (let ((v (dict-ref m k)))
+     (if (string? v)
+	 (dict-set m k (string->month v))
+	 m)))
+
  ;; All conversions in one place
  (define (convert-member-keys m)
-   (convert-member-keys:card
-    (convert-member-key:credit
-     (convert-member-keys:markers->periods m 'suspend 'student))
-    'card 'desfire))
+   (convert-member-key:month
+    (convert-member-keys:card
+     (convert-member-key:credit
+      (convert-member-keys:markers->periods m 'suspend 'student))
+     'card 'desfire)
+    'joined))
 
  ;; Fills-in the defaults
  (define (make-default-member-info)
    (dict-set
     (make-dict)
     'joined
-    "2015-01"))
+    (*member-default-joined*)))
 
  ;; Processes all lines and returns a dictionary representing given
  ;; member. 

members-base.scm

@@ -53,7 +53,8 @@
 	 member-file
 	 primes
 	 member-record
-	 ansi)
+	 ansi
+	 period)
 
  ;; Gets all files and symbolic links from given directory. The
  ;; symbolic links are represented by cons cells with car being the
@@ -273,8 +274,17 @@
 	  (di4 (dict-set di3 'students
 			 (filter-members-by-predicate mb member-student?)))
 	  (di5 (dict-set di4 'destroyed
-			 (filter-members-by-predicate mb member-destroyed?))))
-     di5))
+			 (filter-members-by-predicate mb member-destroyed?)))
+	  (di6 (dict-set di5 'month (*current-month*))))
+     di6))
+
+ ;; Returns a list two lists: keys, data.
+ ;; Each data record contains values for all keys.
+ (define (members-base-stats . args)
+   (let ((keys '(month total active suspended students destroyed invalid)))
+     (let mloop ((data '())
+		 (month '(2015 1))) ; TODO: *oldest-month*
+       #f)))
 
  ;; Basic information about members-base in human-readable form.
  (define (print-members-base-info mb)

month.scm

@@ -28,6 +28,7 @@
 (module
  month
  (
+  make-month
   month-valid?
   string->month
   month->string
@@ -44,6 +45,10 @@
 	 (chicken format)
 	 testing)
 
+ ;; Simple wrapper for creating month representation as a list.
+ (define (make-month y m)
+   (list y m))
+
  ;; Returns true if this is a valid month representation - a list with
  ;; two integer elements within the allowed range.
  (define (month-valid? m)