History variables: Difference between revisions

Content added Content deleted

Inline

@@ Line 551: / Line 551: @@
 </lang>
 =={{header|Elena}}==
-ELENA 3.2 :
+ELENA 3.4 :
 <lang elena>import extensions.
 import system'collections.
 import system'routines.
 import extensions'routines.
 class HistoryVariable
 {
+    T<Stack> _previous := Stack new.
     object prop Value :: _value.
-    stack  _previous := Stack new.
     set Value:v
     [
-        if ($nil != _value)
+        if (nil != _value)
         [
             _previous push(_value)
         ].
         _value := v
     ]
     undo
     [
@@ Line 579: / Line 580: @@
         ];
         [
-            _value := $nil
+            _value := nilValue
         ]
     ]
     enumerator => _previous.
-    dispatch => _value.
+    T<literal> literal => _value.
 }
-program =
+public program
 [
     var o := HistoryVariable new.
@@ Line 594: / Line 595: @@
     o Value := "foo".
     o Value := o Value + "bar".
     console printLine(o).
     o forEach:printingLn.
     o undo; undo; undo.
     console printLine(o Value).
-].</lang>
+]</lang>
 {{out}}
 <pre>