Changes between Version 2 and Version 3 of Attributes

Timestamp:

01/28/13 07:54:38 (11 years ago)

Author:

hopscc

Comment:

--

Attributes

@@ -1 @@
-== Attributes ==
-Cobra has the same type of declarations of attributes just like C# but without square brackets and using the has keyword before the attribute
-You also declare the attribute after declaring the variable.
+= Attributes =
 
-You can add attributes to classes and functions and variables also properties e.g. In GTK
+Attributes are items of metadata appended to specific program items that end up supplied with your program.[[BR]]
+
+Some of these are given as of standard (Types and Members).[[BR]]
+
+User defined or Custom attributes can be declared and given to specify additional information required or desired.[[BR]]
+
+These attributes provided can be then queried by standard or additional tools or by runtime examination (reflection).
+
+Cobra provides for the declaration and use of attributes similarly to  C# ( on .Net) and Java Language (on Jvm).
+These are declared using a keyword prefix ('''has''') with the Attribute (or comma separated Attributes) following 
+(similar in form to a cobra Type declaration) rather than a leading syntactic punctuated clause 
+(C# square brackets or Java @named-annotation).
+
+Minimally, Attributes can be provided on classes and methods, class Fields and properties.
+
+== Grammar ==
+
+{{{
+... has <Attribute>[, <Attribute> ...]
+}}}
+
+may be optionally appended to the declaration of a Type (Class, Struct, Interface, Mixin, Enum, Extension, Event, Signature ) or
+to a Types Field ('''vars'''), Methods and Properties to provide an Attribute or Attributes on that item.
+
+They can also be given on a methods parameters or an Assembly declaration.
+
+== Examples ==
+
+With respect to GTK
+
 {{{
 #!cobra
-class HasAnAttribute
-  has TreeNode(listOnly=true)
+class NameTreeNode
+  has TreeNode(listOnly=true)  # this is an attribute ( with args)
 
   var name is String
@@ -15 +42 @@
     pass
 }}}
+
+
+In the following, A and B.oldMethod are marked obsolete with the System.Obsolete Attribute.
+(This is a .Net common attribute - in cobra it would read better if named '!IsObsolete' or '!ObsoleteMarkerAttribute')
+ 
+{{{
+#!cobra
+class A has Obsolete("use class B")
+
+    def Method
+        pass
+
+class B
+    
+    def oldMethod has Obsolete("use NewMethod", true)
+        pass
+
+    def newMethod
+        pass
+
+}}}
+
+
+== Platform ==
+
+In .Net custom attributes can be defined by defining a class subclassed from System.Attribute.
+Attributes are named in Cobra as per declaration and use in C#.
+
+
+For Java, (.Net) Attributes are known as Annotations. The cobra declaration uses the same prefix but
+uses (subclasses) from Java Annotation definitions.
+
+
+== See Also == 
+
+[http://msdn.microsoft.com/en-us/library/z0w1kczw.aspx C# Attributes]
+
+[http://msdn.microsoft.com/en-us/library/sw480ze8.aspx C# Custom Attributes]
+
+[http://msdn.microsoft.com/en-us/library/z371wyft.aspx C#/.Net Common Attributes]