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SCOPE RESOLUTION OPERATOR






EXAMPLE:
class Base;
typedef enum {bin,oct,dec,hex} radix;

task print( radix r, integer n );
$display(" Enum is %s ",r.name());
$display(" Val is %d",n);
endtask
endclass

program main;
initial
begin
Base b = new;
int bin = 123;
b.print( Base::bin, bin ); // Base::bin and bin are different
end
endprogram

RESULT:

Enum is bin
Val is 123




In addition, to disambiguating class scope identifiers, the :: operator also allows access to static members (class properties and methods) from outside the class,



EXAMPLE:
class Base;
typedef enum {bin,oct,dec,hex} radix;

task print( radix r, integer n );
$display(" Enum is %s ",r.name());
$display(" Val is %d",n);
endtask
endclass

program main;

initial
begin
int bin = 123;
Base::print( Base::bin, bin ); // Base::bin and bin are different
end
endprogram

RESULT:

Enum is bin
Val is 123




Scope resolution operator :: can be used to access to public or protected elements of a superclass from within the derived classes.


EXAMPLE:
class Base;
typedef enum {bin,oct,dec,hex} radix;
endclass

class Ext extends Base;
typedef enum {dec,hex,bin,oct} radix;

task print();
$display(" Ext classs :: enum values %d %d %d %d ",bin,oct,dec,hex);
$display(" Base classs :: enum values %d %d %d %d ",Base::bin,Base::oct,Base::dec,Base::hex);
endtask

endclass

program main;
initial
begin
Ext e;
e = new();
e.print();
end
endprogram
RESULT:

Ext classs :: enum values 2 3 0 1
Base classs :: enum values 0 1 2 3




In SystemVerilog, the class scope resolution operator applies to all static elements of a class: static class properties, static methods, typedefs, enumerations, structures, unions, and nested class declarations. Class scope resolved expressions can be read (in expressions), written (in assignments or subroutines calls), or triggered off (in event expressions). They can also be used as the name of a type or a method call.







The class scope resolution operator enables the following:
Access to static public members (methods and class properties) from outside the class hierarchy.
Access to public or protected class members of a superclass from within the derived classes.
Access to type declarations and enumeration named constants declared inside the class from outside the class hierarchy or from within derived classes.


Index
Introduction
Class
Object
This
Inheritance
Encapsulation
Polymorphism
Abstract Classes
Parameterised Class
Nested Classes
Constant
Static
Casting
Copy
Scope Resolution Operator
Null
External Declaration
Classes And Structures
Typedef Class
Pure
Other Oops Features
Misc

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