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josh11bandRichard Smith
f4e9063b97
Allowing interfaces to define default values for its associated entities. This:
- Helps with evolution by reducing the changes needed to add new members to an interface.
- Reduces boilerplate when some value is more common than others.
- Addresses the gap between the minimum necessary for a type to provide the desired functionality of an interface and the breadth of API that user's desire.
As an alternative, final values can be provided instead, which can't be overridden, but are more predictable for users and may avoid dynamic dispatch overhead in some cases.
Example:
```
// Interface parameter has a default of `Self`
interface Add(Right:! Type = Self) {
// `AddWith` *always* equals `Right`
final let AddWith:! Type = Right;
// `Result` has a default of `Self`
let Result:! Type = Self;
fn DoAdd[me: Self](right: Right) -> Result;
}
impl String as Add() {
// Right == AddWith == Result == Self == String
fn DoAdd[me: Self](right: Self) -> Self;
}
```
Co-authored-by: Richard Smith <richard@metafoo.co.uk>
Generics
This directory contains the collection of documents describing the generics feature of Carbon:
- Overview - A high-level description of the generics design, with pointers to other design documents that dive deeper into individual topics.
- Goals - The motivation and principles guiding the design direction.
- Terminology - A glossary establishing common terminology for describing the design.
- Detailed design - In depth description of how generic type parameters work.
Rejected alternatives- not implemented yet