--- a/Character.st	Fri Jul 19 21:32:37 2019 +0200
+++ b/Character.st	Sun Jul 21 07:54:48 2019 +0200
@@ -1457,25 +1457,31 @@
 !
 
 digitValue
-    "return my digitValue for any base (up to 37)"
+    "return my digitValue for any base (up to 37).
+     Notice: in case of an invalid character,
+             ST/X is not X3J20 conform:
+                ST/X raises an error,
+                X3J20 returns -1"
 
     |code "{ Class: SmallInteger }" |
 
     code := asciivalue.
     (code between:($0 codePoint) and:($9 codePoint)) ifTrue:[
-	^ code - $0 codePoint
+        ^ code - $0 codePoint
     ].
     (code between:($a codePoint) and:($z codePoint)) ifTrue:[
-	^ code + (10 - $a codePoint)
+        ^ code + (10 - $a codePoint)
     ].
     (code between:($A codePoint) and:($Z codePoint)) ifTrue:[
-	^ code + (10 - $A codePoint)
+        ^ code + (10 - $A codePoint)
     ].
 
 "remove error below for X3J20 conformance ... "
     self error:'bad character'.
 " "
     ^ -1
+
+    "Modified (comment): / 21-07-2019 / 07:54:30 / Claus Gittinger"
 !
 
 digitValueRadix:base