Differences

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--- at:tutorial:objects [2007/07/09 21:38] – rewrote tvcutsem
+++ at:tutorial:objects [2007/07/10 12:46] – fixed tvcutsem
@@ Line 51: / Line 51: @@
 </code>
-Every object understands the message ''new'', which creates a clone (a shallow copy) of the receiver object and initializes the clone by invoking its ''init'' method with the arguments that were passed to new (''aX'' and ''aY'' in the example code). Hence, the ''init'' method plays the role of "constructor" for AmbientTalk objects. Hence, in the code above, ''anotherPoint'' shares its methods with its ''Point'' prototype, but it has its own set of fields:
+Every object understands the message ''new'', which creates a clone (a shallow copy) of the receiver object and initializes the clone by invoking its ''init'' method with the arguments that were passed to new (''aX'' and ''aY'' in the example code). Hence, the ''init'' method plays the role of "constructor" for AmbientTalk objects. In the above code, ''anotherPoint'' shares its methods with its ''Point'' prototype, but it has its own set of fields:
 <code>
@@ Line 101: / Line 101: @@
 In this example, ''Point3D'' delegates any message it does not understand to ''Point''. The ''extend:with:'' construct creates a new object whose ''super'' slot is automatically set to the given parent object. The delegation relationship is **IS-A** because a ''Point3D'' is a kind of 2D ''Point'', and a ''z'' coordinate (conceptually) cannot exist without a corresponding ''x'' and ''y'' coordinate.
-A **SHARES-A** relationship between two objects signifies that an object only delegates to another object purely for reasons of code sharing. The delegation link has no other semantics, and conceptually both parent and child can exist without one another.
+A **SHARES-A** relationship between two objects signifies that an object only delegates to another object purely for reasons of code or state sharing. The delegation link has no other semantics, and conceptually both parent and child can exist without one another.
 The following code shows how to extend objects with a **SHARES-A** delegation relationship. It uses the ''share: with:'' language construct.
@@ Line 141: / Line 141: @@
 ===== First-class delegation =====
-AmbientTalk provides an explicit delegation operator ''^'' (the "caret" or "hat" symbol). The code below illustrates the use of the ''^'' operator in the implementation of the ''init'' method of the ''point3D'' object.
+AmbientTalk provides a special message-sending operator ''^'' (the "caret" or "hat" symbol) to express the //explicit// delegation of a message to an object. The code below illustrates the use of the ''^'' operator in the implementation of the ''init'' method of the ''point3D'' object.
 <code>
-> def point3D := extend: point with: {
+def point3D := extend: point with: {
-    def z := 0;
+  def z := 0;
-    def init(aX, aY, aZ) {
+  def init(aX, aY, aZ) {
-      super^init(aX, aY);
+    super^init(aX, aY);
-      z := aZ;
+    z := aZ;
-    };
+  };
-  }
+}
 </code>
-A message sent to an object using the ''^'' symbol (e.g. to the parent object in the example above) will start the method lookup in this object (and its parents) and then execute the method body in the lexical scope of the message sender (''self'' is bound to the message sender).
+A message sent to an object using the ''^'' symbol (e.g. to the parent object in the example above) will start the method lookup in this object (and its parents) and then execute the method body with the ''self'' pseudovariable bound to the message sender.
 <note warning>