Issue #6219 has been updated by MartinBosslet (Martin Bosslet).


nobu (Nobuyoshi Nakada) wrote:
> Calling default proc can be expensive.  So I don't think it's good idea to call it always.
> A patch to separate Hash#store from Hash#[]=, and let it return the old value.

You are right, the default proc is a real "party pooper" here... Could something like Rodrigo 
proposed work for the default proc case? Did you mean something like it when you proposed 
separating Hash#store from #[]=, or did you think about something different?


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Feature #6219: Return value of Hash#store
https://bugs.ruby-lang.org/issues/6219#change-25415

Author: MartinBosslet (Martin Bosslet)
Status: Assigned
Priority: Low
Assignee: matz (Yukihiro Matsumoto)
Category: core
Target version: 3.0


Hash#store returns the value that was just assigned, for example:

  h[:a] = b # => b

Does anyone rely on this behavior, are there cases when this becomes handy?

If however the return value is discarded most of the time, I was thinking it 
might be beneficial if we would return the previous value of a given key (nil if
none was assigned yet) instead. That way we could assign and check for a collision
in one pass, something that right now can only be done in two separate steps.




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