Parameterized Clases

[zhon1231]

Hi all,

I am in the middle of writing a parametrized class, and I hit a road block. Is there a way I can overwrite a parameter in the type_id::create call?

For example, can I do something similar to this?

Class A #(int j=10)

....

endclass

Class B

A m_a;

function void build();

case(mode)

0: m_a = A#(7)::type_id::create(...);

1: m_a = A#(2)::type_id::create(...);

2: m_a = A#(11)::type_id::create(...);

default: m_a = A#(4)::type_id::create(...);

endcase

endfunction

endclass

Any comment is greatly appreciated!

Thanks,

Billy

endclass

[dave_59]

You would need to have A extended from a common base class so that m_a could be assigned with any specialization of A. As you have written it

A m_a; // is the same as

A #() m_a; // which is the same as

A #(10) m_a;

It would be better to write

virtual class A_base;
  pure virtual methods...
endclass 
class A #(int j) extends A_base;
endclass

A_base m_a;

and your build method would be the same.

You should be careful about what you choose to parametrize in a class. Take a look at the DVCon paper I reference at the bottom of my blog article on parameters.

BTW, writing class A #(int j) without a default assignment means that you are required to have A #(something) when you reference it. Then A obj_h; would be illegal

Edited November 29, 2011 by dave_59