[Python-Dev] Guarantee ordered dict literals in v3.7? (original) (raw)

Stephen J. Turnbull turnbull.stephen.fw at u.tsukuba.ac.jp
Thu Dec 21 22:51:36 EST 2017

Chris Barker writes:

Nathaniel Smith has pointed out that eval(pprint(a_dict)) is supposed to return the same dict -- so documented behavior may already be broken.

Sure, but that's because we put shoes on a snake. Why anybody expects no impediment to slithering, I don't know!

I understand the motivation to guarantee order, but it's a programmer convenience that has nothing to do with the idea of mapping, and the particular (insertion) order is very special and usually neither relevant nor reproducible. I have no problem whatsoever with just documenting any failure to preserve order while reproducing dicts, except that a process that inserts keys in the same order had better result in the same insertion order.

Steve

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