[Python-Dev] Add a frozendict builtin type

[R. David Murray]

On Thu, 01 Mar 2012 16:50:06 -0800, Guido van Rossum <guido at python.org> wrote:
> On Thu, Mar 1, 2012 at 4:39 PM, Victor Stinner <victor.stinner at gmail.com> wrote:
> > frozendict could be used to implement "read-only" types: it is not possible
> > to add or remove an attribute or set an attribute value, but attribute value
> > can be a mutable object. Example of an enum with my type_final.patch
> > (attached to issue #14162).
[...]
> 
> I think you should provide stronger arguments in each case why the
> data needs to be truly immutable or read-only, rather than just using
> a convention or an "advisory" API (like __private can be circumvented
> but clearly indicates intent to the reader).

+1.  Except in very limited circumstances (such as a security sandbox)
I would *much* rather have the code I'm interacting with use advisory
means rather than preventing me from being a consenting adult.  (Having to
name mangle by hand when someone has used a __ method is painful enough,
thank you...good thing the need to do that doesn't dome up often (mostly
only in unit tests)).

--David