[Python-ideas] Expose a child factory using MappingProxyType in builtins

[Joseph Hackman]

+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 at 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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