Searching MappingProxyType on GitHub gives over 10,000 results.
I think it probably makes sense to make mappingproxy more "visible",
maybe move it to collections module? (where OrderedDict lives)

I am not sure if it makes sense to move it to builtins. (for comparison frozenset gives around 1000,000 results)

--

Ivan

On 28 February 2017 at 16:24, Joseph Hackman <josephhackman@gmail.com> wrote:

+1

I think this makes a lot of sense. What would you name the built in?

-Joseph

> On Feb 28, 2017, at 7:17 AM, Michel Desmoulin <desmoulinmichel@gmail.com> wrote:
>
> We have the immutable frozenset for sets and and tuples for lists.
>
> But we also have something to manipulate dict as immutable datastructures:
>
>>>> from types import MappingProxyType as idict
>>>> d = idict({'a':1, 'b':2, 'c':3})
>>>> d['a'] = 4
> Traceback (most recent call last):
>  File "<ipython-input-3-c6f93d6278af>", line 1, in <module>
>    d['a'] = 4
> TypeError: 'mappingproxy' object does not support item assignment
>
> We could expose this as a built type to allow the last of the most
> important data structure in Python to be easily immutable.
>
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