Feature: Swift exceptions #554
Comments
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Any chance you can draft a minimal solution? |
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The pattern in Objective-C that was widely used for errors (exceptions are closer to a panic/fatal error, but not quite), was to pass in an error pointer and have the function set that on return. This pattern was widely enough used that the Objective-C to Swift translation layer understands it with a given attribute and converts it to a thrown Swift error. Example: - (UInt32)filteredSearchSingle:(Float32 const *_Nonnull)vector
count:(UInt32)wanted
filter:(USearchFilterFn)predicate
keys:(USearchKey *_Nullable)keys
distances:(Float32 *_Nullable)distances
error:(NSError **)errorPtr __attribute__((swift_error(nonnull_error))){
search_result_t result = _native->filtered_search(vector, static_cast<std::size_t>(wanted), predicate);
if (!result) {
*errorPtr = [NSError errorWithDomain:@"YourErrorDomain"
code:100
userInfo:@{NSLocalizedDescriptionKey: [NSString stringWithUTF8String:result.error.release()]}];
return 0;
}
std::size_t found = result.dump_to(keys, distances);
return static_cast<UInt32>(found);
}do {
try index.filteredSearchSingle(vec, count: 10, filter: fn, keys: nil, distances: nil)
} catch {
println(error)
} |
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@danpalmer, will it still work with the older ObjC code or do we need to add new APIs to avoid breaking changes? |
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This would be backwards-incompatible, although in my opinion a strong improvement to the ObjC API. From my (outdated?) experience, error passing was more common than NSException, and more idiomatic. |
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@danpalmer, can you please submit a draft of a breaking change and I'll incorporate it into the next major release? |
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Drafted here: #555 |
Describe what you are looking for
Currently the Swift bindings are just generated from Objective-C. Unfortunately Objective-C uses a different error/exception model to Swift.
Currently, errors are thrown as
NSExceptions. These are impossible to catch in Swift, and therefore cause a crash.It would be great if these were thrown as Swift Exceptions. The Swift/Obj-C translation process can automate part of this with annotations.
Can you contribute to the implementation?
Is your feature request specific to a certain interface?
Other
Contact Details
No response
Is there an existing issue for this?
Code of Conduct
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