Delegates: Difference between revisions

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@@ Line 754: / Line 754: @@
 =={{header|Elena}}==
-ELENA 3.4 :
+ELENA 4.x :
 Using multi methods:
-<lang elena>import extensions.
+<lang elena>import extensions;
-import system'routines.
+import system'routines;
 interface IOperable
 {
-    abstract operate []
+    abstract operate() {}
 }
-class Operable :: IOperable
+class Operable : IOperable
 {
-    constructor new []
+    constructor() {}
-    operate
+    operate()
-        = "delegate implementation".
+        = "delegate implementation";
 }
 class Delegator
 {
-    object theDelegate.
+    object theDelegate;
-    set Delegate:object
-    [
-        if(nil == object)
-        [
-            theDelegate := nilValue.
-        ];
-        [
-            theDelegate := object.
-        ]
-    ]
-    private operate(object operable)
+    set Delegate(object)
+    {
-        = "default implementation".
+        theDelegate := object
+    }
-    private operate(IOperable operable)
+    internal operate(operable)
-        = operable operate.
+        = "default implementation";
-    operate
+    internal operate(IOperable operable)
-        <= operate(theDelegate).
+        = operable.operate();
+    operate()
+        <= operate(theDelegate);
 }
-public program
+public program()
+{
-[
-    var delegator := Delegator new.
+    var delegator := new Delegator();
-    (nil, Object new, Operable new) forEach(:o)
+    new object[]{nil, new Object(), new Operable()}.forEach:(o)
-    [
+    {
-       delegator Delegate := o.
+       delegator.Delegate := o;
-       console printLine(delegator operate).
+       console.printLine(delegator.operate())
-    ].
+    }
-]</lang>
+}</lang>
 Generic solution:
-<lang elena>import extensions.
+<lang elena>import extensions;
-import system'routines.
+import system'routines;
 class Operable
 {
-    operable = self.
+    Operable = self;
-    operate
+    operate()
-        = "delegate implementation".
+        = "delegate implementation";
 }
 class Delegator
 {
-    object prop Delegate :: theDelegate.
+    prop object Delegate;
-    constructor new
+    constructor()
-    [
+    {
-        theDelegate := nil.
+        Delegate := nil
-    ]
+    }
-    operate
+    operate()
-    [
+    {
         // if the object does not support "get&operable" message - returns nil
-        var anOperable := theDelegate operable \ back:nil.
+        var operable := Delegate.Operable \ back:nil;
-        if (nil == anOperable)
+        if (nil == operable)
-        [
+        {
-            ^ "default implementation".
+            ^ "default implementation"
-        ];
+        }
-        [
+        else
-            ^ anOperable operate.
+        {
-        ].
+            ^ operable.operate()
-    ]
+        }
+    }
 }
-public program
+public program()
+{
-[
-    var delegator := Delegator new.
+    var delegator := new Delegator();
-    (nil, Object new, Operable new) forEach(:o)
+    new object[]{nil, new Object(), new Operable()}.forEach:(o)
-    [
+    {
-       delegator Delegate := o.
+       delegator.Delegate := o;
-       console printLine(delegator operate).
+       console.printLine(delegator.operate())
-    ].
+    }
-]</lang>
+}</lang>
 {{out}}
 <pre>