Does anyone know how to D1-ify this (from D2 std.contracts)

In particular I don't understand what those fancy D2 is-expressions are doing.

---------------

bool pointsTo(S, T)(ref S source, ref T target)
{
    static if (is(S P : U*, U))
    {
        const void * m = source, b = &target, e = b + target.sizeof;
        return b <= m && m < e;
    }
    else static if (is(S == struct))
    {
        foreach (i, subobj; source.tupleof)
        {
            if (pointsTo(subobj, target)) return true;
        }
        return false;
    }
    else static if (is(S A : U[], U))
    {
        const void* p1 = source.ptr, p2 = p1 + source.length,
            b = &target, e = b + target.sizeof;
        return overlap(range(p1, p2), range(b, e)).length != 0;
    }
    else
    {
        return false;
    }
}
-----------------

thanks
--bb

Bill Baxter wrote:
> Does anyone know how to D1-ify this (from D2 std.contracts)
> 
> In particular I don't understand what those fancy D2 is-expressions are doing.
> 

I think I got it.

This in D2

> 
>     static if (is(S P : U*, U))

Is another way to say this

      static if (is(S U : U*))

>     else static if (is(S A : U[], U))


Same here -- it's equivalent to   "if(is(S U : U[]))"

--bb