Joel de Guzman wrote:
Eric Niebler wrote:
BOOST_TYPEOF can't perfectly distinguish between lvalues and rvalues.
Yeah, that's my basic problem with BOOST_TYPEOF.
I fudge it where I have to,
Where do you fudge it? if_then expression? How? How about ordinary operators like a + b? Do you simply not allow weird uses like:
X& operator+(A a, B b)
return a reference??
I use BOOST_TYPEOF to get the type of an expression. Then, I check to see if the expression can bind to a non-const reference using the sizeof trick. If it does, then I treat the result as an lvalue and add a reference to the expression's type. It gets the answer wrong for const-qualified rvalues, but in the above example, it would correctly deduce the type of "A()+B()" to be "X&". -- Eric Niebler BoostPro Computing http://www.boostpro.com