[cxx-interop] Add CxxSequence protocol to the stdlib overlay
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| /// Returns the unwrapped result of C++ `operator*()`. | ||
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| /// Generally, Swift creates this property automatically for C++ types that define `operator*()`. | ||
| var pointee: Pointee { get } |
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Name chosen to match UnsafePointer.pointee/UnsafeMutablePointer.pointee and the synthesized properties for operator*().
| var pointee: Pointee { get } | ||
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| /// Returns an iterator pointing to the next item in the sequence. | ||
| func successor() -> Self |
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Name chosen to match UnsafePointer.successor()/UnsafeMutablePointer.successor(): I think we should try to avoid adding public methods/properties to Swift stdlib classes like UnsafePointer as much as possible, and reusing the existing name allows us to define an empty extension with no public methods.
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test/Interop/Cxx/stdlib/overlay/custom-sequence-typechecker.swift
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| // REQUIRES: OS=macosx || OS=linux-gnu | ||
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| import CustomSequence | ||
| import std |
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Can you add a test for std.string and/or std.vector? (Maybe in another file.)
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Or better yet: update the existing string/vector tests.
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Yeap, added a test for std::string. std::vector is more tricky because it's a template type.
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| for item in seq { | ||
| print(item) | ||
| } |
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Simply executing the code without validating the results doesn't seem like an adequate test.
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This is a typechecker test, we're not actually executing any code here. This test makes sure that the typechecker doesn't emit any unexpected warnings or remarks.
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@swift-ci please smoke test |
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| extension UnsafePointer: UnsafeCxxInputIterator {} | ||
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| extension UnsafeMutablePointer: UnsafeCxxInputIterator {} |
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Can you conform Optional<UnsafePointer> to UnsafeCxxInputIterator? That way you can allow nullable pointers returned from begin/end, which some empty containers can return.
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That's a great idea, thanks!
That currently means that we have to add new public members to Optional<UnsafePointer> (pointee & successor()), which I think would be best to avoid, since users might start relying on them in non-interop code, but I'll think about how to hide those members a bit later. We can probably fix that by introducing a separate private iterator protocol.
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Just to confirm: if c++ interop is not enabled, people won't get the overlay, therefore won't see these members/conformances?
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That is correct, these conformances will only be visible when C++ interop is enabled.
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This change adds basic helper protocols and structs that are going to be used for making C++ sequences and collection safe and Swifty by adding conformances to `Swift.Sequence`, `Swift.Collection`, etc. This is not meant to be a final design.
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This change adds basic helper protocols and structs that are going to be used for making C++ sequences and collection Swifty by adding conformances to
Swift.Sequence,Swift.Collection, etc.This is not meant to be a final design.