[Python-Dev] PEP 416: Add a frozendict builtin type

[David Malcolm]

On Wed, 2012-02-29 at 19:21 +0100, Victor Stinner wrote:
> As requested, I create a PEP and a related issue:
> 
> http://www.python.org/dev/peps/pep-0416/

[...snip...]

> 
> Rationale
> =========
> 
> A frozendict mapping cannot be changed, but its values can be mutable
> (not hashable). A frozendict is hashable and so immutable if all
> values are hashable (immutable).
The wording of the above seems very unclear to me.

Do you mean "A frozendict has a constant set of keys, and for every key,
d[key] has a specific value for the lifetime of the frozendict.
However, these values *may* be mutable.  The frozendict is hashable iff
all of the values are hashable." ?  (or somesuch)

[...snip...]

>  * Register frozendict has a collections.abc.Mapping
s/has/as/ ?

[...snip...]

> If frozendict is used to harden Python (security purpose), it must be
> implemented in C. A type implemented in C is also faster.

You mention security purposes here, but this isn't mentioned in the
Rationale or Use Cases

Hope this is helpful
Dave