[sv-ec] Virtual interface, virtual other things

We have virtual [interface] which allows us to hook
an object to a (statically elaborated) interface instance
at runtine.  A standard idiom for using this feature is
for a modport to export a clocking block to the client
object...

interface I (input bit clk);
  logic A, B;
  clocking C @(posedge clk);
    input #1step A;
    output #0 B;
  endclocking : C
  modport M(clocking C);
endinterface : I
...
class X;
  virtual I.M V;
  ...
    @(V.C) if (V.C.A) V.C.B <= '0;
  ...
endclass : X

This is good, but note the extreme clumsiness of
the repeated "V.C." paths.  Is there any insuperable
difficulty with creating some more "virtual" types,
and in particular a "virtual clocking"?

class X2; // speculative use of virtual clocking
  virtual interface I.M V;  // prefer "interface" to be explicit now
  virtual clocking I.M.C C;
  ...
    C = V.C;
  ...
    @(C) if (C.A) C.B <= '0;
  ...
endclass : X2

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Even more speculatively: would that allow me to say
  virtual clocking C;
  default clocking C;
so that I can freely use ## cycle-delay syntax within
my class?  Probably not, because of the possibility of
C being null, or being re-targeted, at runtime.

Thanks
-- 
Jonathan Bromley, Consultant

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