--- a/compiler/extensions.st	Tue Aug 18 21:47:50 2015 +0100
+++ b/compiler/extensions.st	Tue Aug 18 22:16:18 2015 +0100
@@ -761,15 +761,32 @@
 !PPSmalltalkWhitespaceParser methodsFor:'*petitcompiler'!
 
 parseOn: aPPContext
-    [ [aPPContext atEnd not and: [ aPPContext uncheckedPeek isSeparator ] ]
-        whileTrue: [ aPPContext next ].
-        
-     aPPContext atEnd not and: [ aPPContext uncheckedPeek = $" ] ] whileTrue: [
-        aPPContext next.
-        "aPPContext upTo: $".
-        
-        [aPPContext atEnd or: [aPPContext next == $"]] whileFalse
+    [ 
+        [aPPContext atEnd not and: [ aPPContext uncheckedPeek isSeparator ] ]whileTrue: [ 
+            aPPContext next 
+        ].
+        aPPContext atEnd not and: [ aPPContext uncheckedPeek = $" ] 
+    ] whileTrue: [
+        aPPContext next. "Eat opening $"
+
+        "When running on Smalltalk/X, also support end-of-line comments "
+        "Here, test first if the char following the opening quote is slash
+         and only if so test for Smalltalk/X as this test is lot slower
+         then slash test"
+        ((aPPContext atEnd not and:[ aPPContext uncheckedPeek == $/ ])
+            and:[(Smalltalk respondsTo: #isSmalltalkX) and:[Smalltalk isSmalltalkX]]) ifTrue:[ 
+                "OK, comment start with quote-slash and we're on Smalltalk/X so eat
+                 everything till the end of a line"
+                | c |
+
+                [ aPPContext atEnd or:[ c := aPPContext next codePoint. c == 13 or:[c == 10] ] ] whileFalse.
+            ] ifFalse:[ 
+                "Standard comment so eat till closing quot"
+                [ aPPContext atEnd or: [ aPPContext next == $" ] ] whileFalse
+            ].
     ].
+
+    "Modified: / 18-08-2015 / 22:13:59 / Jan Vrany <jan.vrany@fit.cvut.cz>"
 ! !
 
 !PPStream methodsFor:'*petitcompiler'!