Home Original page

[Python-Dev] [Python-checkins] peps: PEP 416: remove mentions of mutable/immutable

Terry Reedy tjreedy at udel.edu
Sat Mar 10 17:23:45 CET 2012 
On 3/10/2012 5:43 AM, victor.stinner wrote:
> http://hg.python.org/peps/rev/7278026a5db9
> changeset:   4124:7278026a5db9
> user:        Victor Stinner<victor.stinner at gmail.com>
> date:        Sat Mar 10 11:43:45 2012 +0100
> summary:
>    PEP 416: remove mentions of mutable/immutable
>
> files:
>    pep-0416.txt |  5 ++---
>    1 files changed, 2 insertions(+), 3 deletions(-)
>
>
> diff --git a/pep-0416.txt b/pep-0416.txt
> --- a/pep-0416.txt
> +++ b/pep-0416.txt
> @@ -20,9 +20,8 @@
>   =========
>
>   A frozendict is a read-only mapping: a key cannot be added nor removed, and a
> -key is always mapped to the same value. However, frozendict values can be
> -mutable (not hashable). A frozendict is hashable and so immutable if and only
> -if all values are hashable (immutable).
> +key is always mapped to the same value. However, frozendict values can be not
> +hashable. A frozendict is hashable if and only if all values are hashable.

I think this would be better with 'key is always mapped to the same 
value object'. The revised second sentence does not add anything. Some 
Python objects are hashable and some not. There is nothing special about 
frozendict value objects either way. The proper revision of your 
original is "However, frozendict value may not be hashable." Either 
change to that or remove it.

Terry
More information about the Python-Dev mailing list