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Last week I was asked a couple of questions about called base class constructors, to which I didn't know the answers. So, I did some digging. Firstly, Can you call super.new when there is no explicit constructor in the base class? To which the answer is: yes. I can't think why you'd want to, though. module M;     class C;     bit b;   endclass     class P extends C;     bit b;     function new;       super.new;     endfunction   endclass     C c = new;   endmodule https://www.edaplayground.com/x/3BB9 Can you call super.super.new? To which the answer is: no. Section 8.15 of IEEE 1800-2107 says "There is no way to reach higher (for example, super.super.count is not allowed)." module M;     class C;     bit b;   endclass     class P extends C;     bit b;   endclass;     c...

A customer asked me whether you have a generic virtual interface, which could point at any kind of interface? eg    virtual interface vif; instead of    virtual APB_if vif; I would be nice perhaps. And you'd think it might be possible, because generic interface ports are possible. (See IEEE 1800-2017, section 25.3.3). However, this is one of those questions that I realise I know the answer to as soon as I try to start answering it.    virtual APB_if vif; is actually short for    virtual interface APB_if vif; (ie the " interface " is optional). So, because of that,    virtual interface vif; is clearly nonsense. IEEE 1800-2017, section 25.9 shows the syntax of a virtual interface:     virtual [ interface ] interface_identifier [ parameter_value_assignment ] [ . modport_identifier ]     interface I;       bit b;     endinterf...

A customer asked me whether you could extend a concrete class into an abstract class, by adding a pure virtual function. It turns out you can. IEEE 1800-2012 section 8.21 confirms this: Any class may be extended into an abstract class, and may provide additional or overridden pure virtual methods. module M;     virtual class pure_virtual_base_class;     pure virtual function void foo;   endclass     class concrete_class extends pure_virtual_base_class;     virtual function void foo; endfunction   endclass     virtual class another_pure_virtual_base_class extends concrete_class;     pure virtual function void foofoo;   endclass      endmodule    https://www.edaplayground.com/x/2FpZ A customer asked me about this. I didn't know the answer, so I wrote a few lines of code on EDA Playground. EDA Playground is great for that, because it's always on. You don't hav...