Netflix opensources its first D library: Vectorflow

[Nordlöw via Digitalmars-d-announce]

On Tuesday, 8 August 2017 at 18:40:08 UTC, Nordlöw wrote:
> On Thursday, 3 August 2017 at 04:40:05 UTC, Matt wrote:
>> Also note, one of the main advantages of Eigen is the whole 
>> lazy evaluation of expressions for compound operations.
>>
>> I haven't dug in the source, but it's my understanding it's 
>> done through a lot of compile time C++ template hacking
>
> Note that D provides
>
>     __traits(isRef, Symbol)

To clarify here's an incomplete snippet that should clarify:

auto add(A, B)(A a, B b)
    if (isSomeArithmeticType!A &&
        isSomeArithmeticType!B)
{
    static if (__traits(isRef, a) &&
               __traits(isRef, b)) // both `a` and `b` are l-values
    {
        return a + b; // fully eager evaluation
    }
    else static if (__traits(isRef, a)) // `b` is an r-value
    {
        // `b` can incremented by `a` and returned by move (reused)
    }
    else static if (__traits(isRef, b)) // `a` is an r-value
    {
        // `a` can incremented by `b` and returned by move (reused)
    }
    else // both `a` and `b` are r-values
    {
        return Add(a,b); // delay evaluation
    }
}