Re: NSDictionary design bug (was: Re: Ugly bug in Foundation, beware!)
Re: NSDictionary design bug (was: Re: Ugly bug in Foundation, beware!)
- Subject: Re: NSDictionary design bug (was: Re: Ugly bug in Foundation, beware!)
- From: Marcel Weiher <email@hidden>
- Date: Mon, 7 Jun 2004 19:40:19 +0100
On 6 Jun 2004, at 20:16, Shawn Erickson wrote:
Java's HashMap (near equivalent to NSMutableDictionary since they both
bucket things using hashes) doesn't copy the keys but simply
references them.
And so does every other implementation of the "dictionary" concept I am
aware of, including Smalltalk Dictionaries. In many years of
monitoring the Squeak mailing list, I haven never seen someone with
problems due to keys changing in the dictionary as is suggested, though
I could have missed it (the list has very heavy traffic)
This can introduce different issues, issues in many ways the flip of
what you are noting above but which can results in the same problem
and a much worse problem.
These are the issues you have to deal with when you are programming in
a language with mutable state: the state my mutate! (Surprise)
Throwing in a bit of copying and a bit of "immutability" is not going
to change that fact. At most, it can make people *think* that that
fact has changed, and cause them to make errors.
Cheers,
Marcel
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| References: | |
| | >Ugly bug in Foundation, beware! (From: Ondra Cada <email@hidden>) |
| | >Is that really a bug at all? (was: Re: Ugly bug in Foundation, beware!) (From: Alastair Houghton <email@hidden>) |
| | >Re: Is that really a bug at all? (was: Re: Ugly bug in Foundation, beware!) (From: Ondra Cada <email@hidden>) |
| | >Re: Is that really a bug at all? (was: Re: Ugly bug in Foundation, beware!) (From: Alastair Houghton <email@hidden>) |
| | >Re: Is that really a bug at all? (was: Re: Ugly bug in Foundation, beware!) (From: Brent Gulanowski <email@hidden>) |
| | >Re: Is that really a bug at all? (was: Re: Ugly bug in Foundation, beware!) (From: Alastair Houghton <email@hidden>) |
| | >Re: Is that really a bug at all? (was: Re: Ugly bug in Foundation, beware!) (From: Ondra Cada <email@hidden>) |
| | >Re: Is that really a bug at all? (was: Re: Ugly bug in Foundation, beware!) (From: Marcel Weiher <email@hidden>) |
| | >Re: Is that really a bug at all? (was: Re: Ugly bug in Foundation, beware!) (From: Brent Gulanowski <email@hidden>) |
| | >Re: Is that really a bug at all? (was: Re: Ugly bug in Foundation, beware!) (From: "Louis C. Sacha" <email@hidden>) |
| | >Re: Is that really a bug at all? (was: Re: Ugly bug in Foundation, beware!) (From: Marcel Weiher <email@hidden>) |
| | >Re: Is that really a bug at all? (was: Re: Ugly bug in Foundation, beware!) (From: Nat! <email@hidden>) |
| | >Re: NSDictionary design bug (was: Re: Ugly bug in Foundation, beware!) (From: Marcel Weiher <email@hidden>) |
| | >Re: NSDictionary design bug (was: Re: Ugly bug in Foundation, beware!) (From: Shawn Erickson <email@hidden>) |