Prepare for notifications.

src/members-payments.scm

@@ -32,6 +32,7 @@
   members-payments-process
   member-balance
   member-total-balance
+  members-to-notify
   )
 
  (import scheme
@@ -211,5 +212,17 @@
 		     (else 0))))
 	       (member-payments mr))))
 
+ ;; Return members to notify because of late payments for more than
+ ;; given number of months
+ (define (members-to-notify mb months)
+   (filter-members-by-predicate
+    mb
+    (lambda (mr)
+      (let ((total (member-total-balance mr))
+	    (fee (lookup-member-fee (if (member-student? mr)
+					'student
+					'regular))))
+	(and (< total 0)
+	     (< total (- (* months fee))))))))
 
  )