Re: [boost] new version of array<>

From: Mark Rodgers (mark.rodgers_at_[hidden])
Date: 2000-08-01 03:56:41

> Same urgent questions I have:
> - How to implement a template assignement operator that
>   makes sure that the same number of elements are used?

Is there anything wrong with 

     template <typename T2>
     array &operator=(const array<T2,N> &rhs) {
        std::copy(rhs.begin(),rhs.end(), begin());
        return *this;
     }

This works for me.  Of course, because rhs may be of a 
different type, we can't easily check for self assignment, 
but I don't think we need to.

I'd also like to see one or more assignment functions for
compatibility with vector.  I think these should behave
like strncpy.  If the range contains more than N elements, 
assign the first N to the array.  If the range contains
fewer than N, assign them to the array and "zero-fill"
(i.e. assign T() to) the remainder.

> - Does anybody know whether using "{...}" instead of
>   "{ { ... } }" for initialisation is valid code???

This is tricky.  I don't see why not, but the standard is 
less than clear.  On the one hand I can't find anything in 
the standard the explicitly allows it; on the other hand I 
can't find anything that forbids it, it works with all the 
compilers I've tested, and I think 8.5.1p11 is implying it
is allowed.  So I think it is OK.

Mark