Foundation’s common currency type for errors is unequivocally
`NSError`, and we’re not looking to change that as part of this
proposal.
Reusing errors from the Cocoa domain has always been a reasonable choice
for 3rd-party developers, and we’d like to keep doing this.
We are looking to improve the experience of throwing such errors (with
some trivial extensions) by allowing you to do something like `throw
CocoaError.error(.coderInvalidValue)`. (Of course, don’t quote me on
the exact syntax, as this is totally subject to change.)
This is pretty simple, and nets you free user-facing localization.
On 15 Mar 2017, at 22:46, Zach Waldowski wrote:
Just a little one that came up with when thinking over the companion
proposal… see inline.
On Mar 15, 2017, at 6:43 PM, Itai Ferber via swift-evolution
<[email protected]> wrote:
Foundation-Provided Errors
Along with providing the above encoders and decoders, we would like
to promote the use of a common set of error codes and messages across
all new encoders and decoders. A common vocabulary of expected errors
allows end-users to write code agnostic about the specific
encoder/decoder implementation they are working with, whether
first-party or third-party:
extension CocoaError.Code {
public static var coderInvalidValue: CocoaError.Code
public static var coderTypeMismatch: CocoaError.Code
public static var coderReadCorrupt: CocoaError.Code
public static var coderValueNotFound: CocoaError.Code
}
I find all the reasons compelling, but I don’t with the overall
choice. A common vocabulary, side table info, and localization can be
achieved with a dedicated error type for coders. I understand ABI
(sorta) concerns are involved here, that older Foundations will
continue to return the same NSError codes. However, it's never felt
appropriate to create my own error instances with NSCocoaErrorDomain,
and this feels very similar to that. What are our options here?
Zach Waldowski
[email protected]
_______________________________________________
swift-evolution mailing list
[email protected]
https://lists.swift.org/mailman/listinfo/swift-evolution
