[report-utilities] fix (gnc:make-stats-collector)

allows it to compare numbers with +/-inf.0 -- 10E9 is an arbitrary
number to compare numbers.

(< N +inf.0) is guaranteed to be #t for all numbers N whereby N is not
also +inf.0.

gnucash/report/report-system/report-utilities.scm

@@ -177,40 +177,35 @@ construct gnc:make-gnc-monetary and use gnc:monetary->string instead.")
 ;; yes.  I think that would still be faster.
 
 (define (gnc:make-stats-collector)
-  (let ;;; values
-      ((value 0)
-       (totalitems 0)
-       (max -10E9)
-       (min 10E9))
-    (let ;;; Functions to manipulate values
-	((adder (lambda (amount)
-		  (if (number? amount) 
-		      (begin
-			(set! value (+ amount value))
-			(if (> amount max)
-			    (set! max amount))
-			(if (< amount min)
-			    (set! min amount))
-			(set! totalitems (+ 1 totalitems))))))
-	 (getnumitems (lambda () totalitems))
-	 (gettotal (lambda () value))
-	 (getaverage (lambda () (/ value totalitems)))
-	 (getmax (lambda () max))
-	 (getmin (lambda () min))
-	 (reset-all (lambda ()
-		    (set! value 0)
-		    (set! max -10E9)
-		    (set! min 10E9)
-		    (set! totalitems 0))))
-      (lambda (action value)  ;;; Dispatch function
-	(case action
-	  ((add) (adder value))
-	  ((total) (gettotal))
-	  ((average) (getaverage))
-	  ((numitems) (getnumitems))
-	  ((getmax) (getmax))
-	  ((getmin) (getmin))
-	  ((reset) (reset-all))
+  (let ((value 0)
+        (totalitems 0)
+        (maximum -inf.0)
+        (minimum +inf.0))
+    (let ((adder (lambda (amount)
+                   (when (number? amount)
+                     (set! value (+ amount value))
+                     (if (> amount maximum) (set! maximum amount))
+                     (if (< amount minimum) (set! minimum amount))
+                     (set! totalitems (1+ totalitems)))))
+          (getnumitems (lambda () totalitems))
+          (gettotal (lambda () value))
+          (getaverage (lambda () (/ value totalitems)))
+          (getmax (lambda () maximum))
+          (getmin (lambda () minimum))
+          (reset-all (lambda ()
+                       (set! value 0)
+                       (set! maximum -inf.0)
+                       (set! minimum +inf.0)
+                       (set! totalitems 0))))
+      (lambda (action value)
+        (case action
+          ((add) (adder value))
+          ((total) (gettotal))
+          ((average) (getaverage))
+          ((numitems) (getnumitems))
+          ((getmax) (getmax))
+          ((getmin) (getmin))
+          ((reset) (reset-all))
           (else (gnc:warn "bad stats-collector action: " action)))))))
 
 (define (gnc:make-drcr-collector)

gnucash/report/report-system/test/test-report-utilities.scm

@@ -22,6 +22,7 @@
   (test-commodity-collector)
   (test-get-account-balances)
   (test-monetary-adders)
+  (test-make-stats-collector)
   (test-end "report-utilities"))
 
 (define (NDayDelta t64 n)
@@ -503,3 +504,50 @@
      "gnc:monetary+ with >1 currency fails"
      #t
      (gnc:monetary+ usd10 usd10 eur8))))
+
+(define (test-make-stats-collector)
+  (test-begin "gnc:make-stats-collector")
+  (let ((s (gnc:make-stats-collector)))
+    (test-equal "initial s is 0"
+      0
+      (s 'total #f))
+
+    (s 'add 5)
+    (test-equal "s+=5 is 5"
+      5
+      (s 'total #f))
+
+    (s 'add 9)
+    (test-equal "s+=9 is 14"
+      14
+      (s 'total #f))
+
+    (test-equal "avg(s) is 7"
+      7
+      (s 'average #f))
+
+    (s 'add 1E12)
+    (s 'add -1E13)
+
+    (test-equal "max(s) is now 1E12"
+      1E12
+      (s 'getmax #f))
+
+    (test-equal "min(s) is now -1E13"
+      -1E13
+      (s 'getmin #f))
+
+    (s 'add 9E12)
+    (test-equal "newavg(s) is 2.8"
+      2.8
+      (s 'average #f))
+
+    (test-equal "num(s) is 5"
+      5
+      (s 'numitems #f))
+
+    (s 'reset #f)
+    (test-equal "after reset num(s) is 0"
+      0
+      (s 'numitems #f)))
+  (test-end "gnc:make-stats-collector"))