On Friday, 6 July 2018 at 13:13:43 UTC, Michael wrote:
static auto ref consensus( ... )
`auto ref` infers the return type from the return statement [1].
So it's not necessarily returning a ref type.
However, I don't think this matters if the only concern you have
is that the setter function actually modifies the passed object.
and the agent's setter method looks like the following:
void beliefs(ref double[int] beliefs)
Now obviously if I remove ref in the above signature,
everything works fine, but I am surprised I wasn't getting any
kind of warning about the reference because the setter function
just doesn't run at all. I tried checking if (beliefs is null)
but perhaps this isn't the correct way to check if an
associative array's reference is no longer reachable?
Some explanation would be great, thanks!
This works for me:
auto create()
{
string[int] dict;
dict[2] = "hello";
return dict;
}
void modifyNoRef(string[int] m)
{
writeln("Address not ref: ", &m);
m[0] = "modified";
}
void modifyRef(ref string[int] m)
{
writeln("Address ref: ", &m);
m[1] = "modified";
}
unittest
{
auto r = create();
writeln("Address r: ", &r);
assert(r.keys.length == 1);
modifyNoRef(r);
assert(r.keys.length == 2);
modifyRef(r);
assert(r.keys.length == 3);
}
So either with ref or not as parameter storage class the assoc.
array is modified. Note the address in the "ref" one is the same
as "r" in the unittest.
[1]: https://dlang.org/spec/function.html#auto-ref-functions
