[issue42348] Language Reference: Set items
Raymond Hettinger
report at bugs.python.org
Fri Nov 13 14:44:22 EST 2020
Raymond Hettinger <raymond.hettinger at gmail.com> added the comment:
I recommend leaving the text as is, and possibly creating a new FAQ entry discussing the relationship between immutability and hashability (something that I consider to be an intermediate or advanced topic).
Other thought:
* The set discussion should remain parallel that for mappings (a few paragraphs) after. That text also discusses immutability
* We've never had a user incident regarding this text, so there is no actual evidence that this current wording is confusing anyone.
* It is common for users to equate hashability with immutability, so I think the current wording is reasonable. My experience with users indicate that "hashable" is more cryptic than "immutable" because the former implies a knowledge of how hash tables work.
* It's easy for us thinking we're helping by making precise distinctions but have the actual effect of making the docs more opaque. That is why first-aid books say "bruise" instead of "subdermal hematoma" :-)
* The word "immutable" is a reasonable first approximation that doesn't require knowledge of hash table mechanics. For the most part, it is how everyday users think about dict keys and set elements.
* That approximation is useful because a fuller discussion would say that if __hash__ is defined, it should do so on fields that don't mutate.
----------
_______________________________________
Python tracker <report at bugs.python.org>
<https://bugs.python.org/issue42348>
_______________________________________
More information about the Python-bugs-list
mailing list