Returning multiple arrays from function - struct or byref the only option?

[Laeeth Isharc via Digitalmars-d-learn]

Hi.

I have to write a bunch of functions that operate on input arrays 
to return multiple output arrays.

In case helpful the inputs are price bars or economic data points 
(datetime, ohlc) and the outputs are nx1 arrays (I won't say 
vectors) of doubles or structs.

What is the best way to return multiple arrays in this kind of 
situation.  In Python I returned a tuple of numpy arrays, and the 
C way would be to pass a pointer to the return destinations, and 
I guess I could do the same in a D way by passing by ref not 
value).

I see that I can return a struct containing dynamic arrays, and 
return it (by value of course).  I have read the forum discussion 
a while back over how to return multiple values, and tried using 
tuples.  I don't see that I can return a tuple of arrays - am I 
missing something?

Here is a simple case.  Can I do better ?

Thanks.


import std.typecons;
import std.stdio;

struct RetStruct
{
	double[] a;
	double[] b;
}

RetStruct myfunction(double x)
{
	RetStruct s;
	double[] a,b;
	a~=x+1.0;
	a~=x+9.0;
	b~=x+2.0;
	b~=x+11.0;
	s.a=a;
	s.b=b;
	return s;
}

void main()
{
	writefln("%s",myfunction(99.0));
}