Re: Kinds of containers

[Andrei Alexandrescu via Digitalmars-d]

On 10/21/2015 10:21 AM, Timon Gehr wrote:


I still think those should be mutable by default in order to have
painless interchangeability with other value type containers. Why should
corresponding ephemeral and persistent containers have different
interfaces?

I assume you envision code using those to look as follows?

FunSet!int a;
a=a.with_(1);
auto b=a;
a=a.with_(2);
a=a.with_(3);
// b = {1}, a={1,2,3};

I think this should be allowed too:

FunSet!int a;
a.insert(1);
auto b=a;
a.insert(2);
a.insert(3);
// b = {1}, a={1,2,3};

One of the two versions should be automatically implemented via UFCS.

I recall you and I discussed this briefly in the past, but forgot the 
conclusion.

So are you saying that a.insert(1) is really rebinding a to be its 
former value plus a new slot? I.e a.insert(1) is the same as a = 
a.with_(1)? That would work, but only if former reads of a refer to the 
old data. E.g.:

FunSet!int a;
auto b = a;
assert(a.empty && b.empty);
a.insert(1);
assert(!a.empty && b.empty);

Right?


Andrei