[boost] PP: detecting a token?

From: Aleksey Gurtovoy (agurtovoy_at_[hidden])
Date: 2003-04-11 15:35:40

Is there a way to detect a particular pre-defined token passed as a
parameter to a macro? If yes, can we fold it into a PP-library primitive so
one can reuse it easily?

For instance, I would like to be able to allow both this:

    MY_MACRO(10, MY_OTHER_MACRO)

and this:

    MY_MACRO(10, default) // use the "default parameter"

Is there a known way to implement it?

TIA,
Aleksey