Container Purity

[Nordlöw via Digitalmars-d-learn]

Is it currently possible for a container such as

https://github.com/economicmodeling/containers/blob/master/src/containers/dynamicarray.d

that uses std.experimental.container

to be completely pure? If not can be made to?

I wonder because only length(), empty(), front() and back() are 
tagged as pure in DynamicArray at

https://github.com/economicmodeling/containers/blob/master/src/containers/dynamicarray.d

are marked as pure. Is there a reason for this?