--- a/MessageTracer.st	Fri Dec 29 15:42:47 2017 +0100
+++ b/MessageTracer.st	Tue Jan 16 17:16:32 2018 +0100
@@ -1,3 +1,5 @@
+"{ Encoding: utf8 }"
+
 "
  COPYRIGHT (c) 1994 by Claus Gittinger
 	      All Rights Reserved
@@ -727,6 +729,7 @@
 trapMethod:aMethod if:conditionBlock
     "arrange for the debugger to be entered when aMethod has been invoked and conditionBlock
      evaluates to true.
+     conditionBlock gets context and method as (optional) arguments.
      The trap is enabled for any process.
      Use unwrapMethod or untrapClass to remove this trap.
      Be careful, to not place a trap on code needed in the debugger (i.e. on scrollBars etc.);
@@ -734,25 +737,25 @@
      entry/leave blocks."
 
     ^ self
-	wrapMethod:aMethod
-	onEntry:[:con |
-	    |conditionFires|
-
-	    Error handle:[:ex |
-		'MessageTrace: error in breakpoint condition caught: ' errorPrint.
-		ex description errorPrintCR.
-	    ] do:[
-		conditionBlock numArgs == 1 ifTrue:[
-		    conditionFires := conditionBlock value:con
-		] ifFalse:[
-		    conditionFires := conditionBlock value:con value:aMethod
-		].
-	    ].
-	    conditionFires == true ifTrue:[
-		BreakpointSignal raiseRequestWith:nil errorString:nil in:con
-	    ]
-	]
-	onExit:LeaveBreakBlock.
+        wrapMethod:aMethod
+        onEntry:[:con |
+            |conditionFires|
+
+            Error handle:[:ex |
+                'MessageTrace: error in breakpoint condition caught: ' errorPrint.
+                ex description errorPrintCR.
+            ] do:[
+                conditionBlock numArgs == 1 ifTrue:[
+                    conditionFires := conditionBlock value:con
+                ] ifFalse:[
+                    conditionFires := conditionBlock value:con value:aMethod
+                ].
+            ].
+            conditionFires == true ifTrue:[
+                BreakpointSignal raiseRequestWith:nil errorString:nil in:con
+            ]
+        ]
+        onExit:LeaveBreakBlock.
 
     "Created: / 18-08-2000 / 22:09:10 / cg"
     "Modified: / 20-10-2010 / 09:38:57 / cg"
@@ -780,6 +783,42 @@
     "Modified: 22.10.1996 / 17:40:06 / cg"
 !
 
+trapMethod:aMethod onReturnIf:conditionBlock
+    "arrange for the debugger to be entered when aMethod returns
+     and conditionBlock evaluates to true.
+     conditionBlock gets retVal, context and method as (optional) arguments.
+     The trap is enabled for any process.
+     Use unwrapMethod or untrapClass to remove this trap.
+     Be careful, to not place a trap on code needed in the debugger (i.e. on scrollBars etc.);
+     if there is a need to trap those, use the low-level wrap-methods, and put a check into the
+     entry/leave blocks."
+
+    ^ self
+        wrapMethod:aMethod
+        onEntry:[:con | ]
+        onExit:[:con :retVal | 
+            |conditionFires|
+
+            Error handle:[:ex |
+                'MessageTrace: error in breakpoint condition caught: ' errorPrint.
+                ex description errorPrintCR.
+            ] do:[
+                conditionBlock numArgs == 1 ifTrue:[
+                    conditionFires := conditionBlock value:retVal
+                ] ifFalse:[
+                    conditionFires := conditionBlock valueWithOptionalArgument:retVal and:con and:aMethod
+                ].
+            ].
+            conditionFires == true ifTrue:[
+                BreakpointSignal raiseRequestWith:nil errorString:nil in:con
+            ].
+            retVal
+        ]
+
+    "Created: / 18-08-2000 / 22:09:10 / cg"
+    "Modified: / 20-10-2010 / 09:38:57 / cg"
+!
+
 untrapAllClasses
     "remove any traps on any class"