Differences

This shows you the differences between two versions of the page.

--- at:tutorial:objects [2007/06/29 08:35] – jorge
+++ at:tutorial:objects [2007/06/29 10:22] – jorge
@@ Line 9: / Line 9: @@
 <code>
-> def Point := object: {
+> def point := object: {
     def x := 0;
     def y := 0;
@@ Line 27: / Line 27: @@
 </note>
-In the example above, the state of the ''Point'' object is composed of ''x'' and ''y'' fields and its behaviour corresponds to the ''init'' and ''sumOfSquares'' methods.
+In the example above, the state of the ''point'' object is composed of ''x'' and ''y'' fields while its behaviour corresponds to the ''init'' and ''sumOfSquares'' methods.
 ===== Sending messages =====
@@ Line 33: / Line 33: @@
 <code>
-> aPoint.x
+> point.x
 >>2
-> aPoint.sumOfSquares()
+> point.sumOfSquares()
 >>13
 </code>
-This code shows two messages sent to the ''aPoint'' object defined above in this section. The ''x'' message acts as an accessor for the ''x'' field. The ''sumOfSquares'' message selects the ''sumOfSquares'' method and evaluates its body.
+This code shows two messages sent to the ''point'' object defined above in this section. The ''x'' message acts as an accessor for the ''x'' field. The ''sumOfSquares'' message selects the ''sumOfSquares'' method and evaluates its body.
 ===== Cloning and instantiation =====
-As said before in this section, AmbientTalk objects are created [[objects#Objects,_fields_and_methods|ex-nihilo]] or by cloning and adapting an existing object. The code below shows the instatiation of a new ''Point'' object by using the cloning semantics.
+As said before in this section, AmbientTalk objects are created [[objects#Objects,_fields_and_methods|ex-nihilo]] or by cloning and adapting an existing object. The code below shows the instatiation of a new ''point'' object by using the cloning semantics.
 <code>
-> def aPoint := Point.new(2,3)
+> def anotherPoint := point.new(2,3)
 >><object:13393187>
 </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 of the ''Point'' object). Hence, the ''init'' method plays the role of “constructor” for AmbientTalk objects. AmbientTalk’s object instantiation protocol closely corresponds to class instantiation in class-based languages, except that the new object is a clone of an existing object, rather than an empty object allocated from a class.
+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 of the ''point'' object). Hence, the ''init'' method plays the role of “constructor” for AmbientTalk objects. AmbientTalk’s object instantiation protocol closely corresponds to class instantiation in class-based languages, except that the new object is a clone of an existing object, rather than an empty object allocated from a class.
 ===== Delegation and Dynamic Inheritance =====
+AmbientTalk features object inheritance or delegation. By means of delegation, an object can reuse and extend the defintion of another. We distinguish two different delegation relationships: **is-a** and **share-a**.
 ===== Delegation and cloning =====