Re: Passing a reference to a returned reference

[Michael via Digitalmars-d-learn]

On Friday, 6 July 2018 at 14:50:39 UTC, Ali Çehreli wrote:
On 07/06/2018 07:36 AM, Michael wrote:
> but not in
> my case, if this is a weird edge-case with setter member
functions?
This is all very interesting but I'm dying to see the code. :) 
Can you change Timoses's code to demonstrate your case?

Ali

I'm just trying to do that now.

Here is what I have in terms of code:

class Agent
{
    private
    {
        double[int] mDict;
    }

    // Setter: copy
    void beliefs(ref double[int] dict)
    {
        import std.stdio : writeln;
        writeln("Setter function.");
        this.mDict = dict;
    }

    // Getter
    auto ref beliefs()
    {
        return this.mDict;
    }
}

class Operator
{
    static auto ref create()
    {
        double[int] dict;
        dict[2] = 1.0;
        dict[1] = 0.0;
        return dict;
    }
}

unittest
{
    import std.stdio : writeln;

    Agent a = new Agent();

    a.beliefs = Operator.create();
    assert(a.beliefs.keys.length == 2);

    writeln(a.beliefs);
}


and here is the output WITH "ref" in beliefs's signature before 
double[int] dict:

➜  dempshaf git:(master) ✗ rdmd -I../ -unittest -main bug_test.d
[2:1, 1:0]

and without "ref":

➜  dempshaf git:(master) ✗ rdmd -I../ -unittest -main bug_test.d
Setter function.
[2:1, 1:0]


I'm surprised it's showing the correct value of the associative 
array, but hopefully this shows my point that it's not printing 
for some reason, when the parameter is ref.