[swift-evolution] [swift-evolution-announce] [Returned for revision] SE-0089: Renaming String.init<T>(_: T)

Patrick Smith pgwsmith at gmail.com
Fri May 27 21:50:21 CDT 2016


Is there any possibility we can break from this? Especially as:

1. ValuePreservingStringConvertible expects its description to be value preserving, but current Cocoa implementations are not.
2. ‘Description’ doesn’t really convey the meaning of ‘value preserving’ in my mind, but is a valuable name for many other use cases.
3. Swift 3 has a wide range of breaking changes for the better.
4. With the presence of ValuePreservingStringConvertible, CustomStringConvertible doesn’t seem to provide much value over CustomDebugStringConvertible?

For string interpolation, I imagine the standard library could fall back to a ‘description’ method for NSObject subclasses.

Thanks,

Patrick

> On 28 May 2016, at 7:49 AM, Dave Abrahams via swift-evolution <swift-evolution at swift.org> wrote:
> 
> 
> on Thu May 26 2016, Patrick Smith <swift-evolution at swift.org> wrote:
> 
>>> On 27 May 2016, at 2:40 PM, Austin Zheng via swift-evolution <swift-evolution at swift.org> wrote:
>>> 
>>> Any of the NSObject subclass candidates may require their
>>> `description`s to be altered to meet the semantics, which may or may
>>> not be an acceptable breaking change.
>> 
>> Do you think it might be worth changing `description` to be named
>> something else? Something more clear, less likely to conflict with
>> ‘real’ properties — ‘description’ doesn’t seem to portray something
>> that is value-preserving. What is the reason for calling it
>> ‘description’?
> 
> The main reason was backward compatibility with Cocoa, which already has
> a “description” property.
> 
>> Especially if NSObject subclasses won’t fit, then why not have a
>> different method that can be strictly value preserving? (Then
>> `description` can stay being an NSObject thing.)
> 
> -- 
> Dave
> 
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