A class can have following members,

• Properties.
• Methods.

Properties can be of following data types.

• reg
• reg [msb:0]
• integer
• string
• event
• class type
• enum type

Properties can be declared as following

• local : Properties are local to object. This is visible only inside the class.
• public: Properties are public, this is by default. This is visible outside the class.
• protected : This is not visible outside the class, but can be accessed by friend/peer/inherited class.

Accessing Properties

An object can be accessed using the dot operator (.). The handle name for the object precedes the dot, followed by the qualifying property name (for example, address, command).

instance_name.property_name

Sharing Class Properties

The static keyword is used to identify a class property that is shared with all instances of the class. A static properties is not unique to a single object (that is, all objects of the same type share the property).

  1 class A {
  2   public  integer data;
  3   local   integer addr;
  4   protected integer cmd;
  5   static integer credits;
  6   task new() {
  7     data = 100;
  8     addr = 200;
  9     cmd  = 1;
 10     credits = 10;
 11   }
 12   task printA() {
 13     printf ("value of data %0d in A\n", data);
 14     printf ("value of addr %0d in A\n", addr);
 15     printf ("value of cmd  %0d in A\n", cmd);
 16   }
 17 }
 18 
 19 class B extends A {
 20   task printB() {
 21     printf ("value of data %0d in B\n", data);
 22     // Below line will give compile error
 23     //printf ("value of addr %0d in B\n", addr);
 24     printf ("value of cmd  %0d in B\n", cmd);
 25   }
 26 }
 27 
 28 class C {
 29   A a;
 30   B b;
 31   task new() {
 32     a = new();
 33     b = new();
 34     b.data = 2;
 35   }
 36   task printC() {
 37     printf ("value of data %0d in C\n", a.data);
 38     printf ("value of data %0d in C\n", b.data);
 39     // Below line will give compile error
 40     //printf ("value of addr %0d in C\n", a.addr);
 41     //printf ("value of cmd  %0d in C\n", a.cmd);
 42     //printf ("value of addr %0d in C\n", b.addr);
 43     //printf ("value of cmd  %0d in C\n", b.cmd);
 44   }
 45 }
 46 
 47 program properties {
 48   C c = new();
 49   c.a.printA();
 50   c.b.printB();
 51   c.printC();
 52   printf("value of credits is %0d\n",c.a.credits); 
 53   printf("value of credits is %0d\n",c.b.credits); 
 54   c.a.credits ++;
 55   printf("value of credits is %0d\n",c.a.credits); 
 56   printf("value of credits is %0d\n",c.b.credits); 
 57   c.b.credits ++;
 58   printf("value of credits is %0d\n",c.a.credits); 
 59   printf("value of credits is %0d\n",c.b.credits); 
 60 }

 value of data 100 in A
 value of addr 200 in A
 value of cmd  1 in A
 value of data 2 in B
 value of cmd  1 in B
 value of data 100 in C
 value of data 2 in C
 value of credits is 10
 value of credits is 10
 value of credits is 11
 value of credits is 11
 value of credits is 12
 value of credits is 12

Tasks or functions, known as methods, can be designated as local, public, or protected. They are public by default. Accessing Object Methods An object´s methods can be accessed using the dot operator (.). The handle for the object precedes the dot, followed by the method.

The this keyword is used to unambiguously refer to properties or methods of the current instance.

  1 class A {
  2   integer i;
  3 
  4   task set_i(integer value) {
  5     this.i = value;
  6   }
  7 }
  8 
  9 program this_ex {
 10   A a = new();
 11   printf("value of i is %0d\n",a.i);
 12   a.set_i(100);
 13   printf("value of i is %0d\n",a.i);
 14  }

 value of i is x
 value of i is 100

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