Differences

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--- at:tutorial:objects [2007/07/05 14:05] – jorge
+++ at:tutorial:objects [2007/07/09 21:00] – * tvcutsem
@@ Line 4: / Line 4: @@
 In AmbientTalk, objects are not instantiated from
 classes. Rather, they are either created ex-nihilo or by cloning
-and adapting existing objects, like prototypes in the SELF programming language. The definition of such a prototypical object contains a number of fields and methods that represent the object's state and behaviour respectively.
+and adapting existing objects, in the spirit of prototype-based programming such as in the SELF programming language. The definition of a prototypical object contains a number of fields and methods that represent the object's state and behaviour respectively.
 The following code illustrates the ex-nihilo creation of an object:
 <code>
-> def point := object: {
+def Point := object: {
-    def x := 0;
+  def x := 0;
-    def y := 0;
+  def y := 0;
-    def init(aX,aY) {
+  def init(aX,aY) {
-      x := aX;
+    x := aX;
-      y := aY;
+    y := aY;
-    };
+  };
-    def sumOfSquares() { x*x + y*y };
+  def sumOfSquares() { x*x + y*y };
-  }
+}
 </code>
-As all definitions in AmbientTalk, objects, fields and methods are defined using the **def** keyword. Fields are defined using a ''def name := value'' syntax while methods are defined using a ''name(parameters) {body}'' syntax.
+The above code defines an //ex-nihilo// created point object and binds it to the variable ''Point''. The object itself does not carry a name (i.e. it is "anonymous"). Like all definitions in AmbientTalk, fields and methods are defined using the ''def'' keyword. Fields are defined using a ''def name := value'' syntax while methods are defined using a ''def name(parameters) {body}'' syntax.
-<note important>
+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.
-AmbientTalk not only supports traditional canonical syntax (e.g. ''o.m(a,b,c)'') but also keyworded syntax (e.g. ''o.at: key put: value'') for method definitions and message sends, as in SmallTalk.
-</note>
-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.
+<note>
+As already explained in the [[at:tutorial:basic|basic programming]] part of the tutorial, AmbientTalk not only supports traditional canonical syntax (e.g. ''o.m(a,b,c)'') but also keyworded syntax (e.g. ''o.at: key put: value''). Keyworded syntax can be used both for method definitions and for message sends.
+For Smalltalk/Self programmers: note that a keyworded message send does require a message sending operator (like ''.'') in between the receiver and the message, which is different from Smalltalk and Self. As will be described in later chapters, AmbientTalk features more than one message sending operator, so the programmer must explicitly specify which one to use.
+</note>
 ===== Sending messages =====