[WIP] Property behaviors #23292
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[WIP] Property behaviors #23292
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…ble. When a variable has a property behavior, wrap the type of the variable in the property behavior type. For example, a property behavior “Lazy” should be written as Lazy<T>. A variable declared as var someLazyInt: Int by Lazy will have a storage type of Lazy<Int>.
When a property behavior contains an initializer init(initialValue:), the initial value provided to a variable using that property behavior will be implicitly passes to the behavior’s init(initialValue:) initializer. This allows property behavior types to opt-in to being initialized implicitly, from a value of their stored type.
When referencing a property that has a property behavior, implicitly reference the `value` of the behavior to see the underlying type of the property.
Implement a very tightly-bound ^ prefix operator to access the behavior of a property that has a behavior, suppressing the implicit “unwrap” that looks at the underlying value.
If a property behavior’s “value” itself has a property behavior, also implicitly unwrap that and allow suppression of any number of levels of that implicit unwrapping with, e.g., ^(^doubleWrapped).
…rap. The ^ binds tightly to an identifier or parenthesized expression, so after forming the suppress-unwrap expression, parse a postfix expression suffix (if any).
DougGregor
added
the
swift evolution pending discussion
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@swift-ci please test source compatibility |
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@swift-ci please test source compatibility release |
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I'm abandoning this approach in favor of #23440 |
AnthonyLatsis
removed
the
swift evolution pending discussion
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A different, experimental take on property behaviors.