[Python-Dev] Add a frozendict builtin type

[Paul Moore]

On 29 February 2012 19:17, Raymond Hettinger
<raymond.hettinger at gmail.com> wrote:
> From this experience, I conclude that adding a frozendict type
> would be a total waste (except that it would inspire more people
> to request frozen variante of other containers).

It would (apparently) help Victor to fix issues in his pysandbox
project. I don't know if a secure Python sandbox is an important
enough concept to warrant core changes to make it possible. However,
if Victor was saying that implementing this PEP was all that is needed
to implement a secure sandbox, then that would be a very different
claim, and likely much more compelling (to some, at least - I have no
personal need for a secure sandbox).

Victor quotes 6 implementations. I don't see any rationale (either in
the email that started this thread, or in the PEP) to explain why
these aren't good enough, and in particular why the implementation has
to be in the core. There's the hint in the PEP "If frozendict is used
to harden Python (security purpose), it must be implemented in C". But
why in the core (as opposed to an extension)? And why and how would
frozendict help in hardening Python?

As it stands, I don't find the PEP compelling. The hardening use case
might be significant but Victor needs to spell it out if it's to make
a difference.

Paul.