swiftlang/swift

[SR-6864] Add a "cycle" method to the standard library

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#49,413 创建于 2018年1月29日

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featuregood first issuestandard libraryswift evolution proposal needed

描述
Previous ID SR-6864
Radar None
Original Reporter @airspeedswift
Type New Feature
Votes 0
Component/s Standard Library
Labels New Feature, StarterProposal
Assignee None
Priority Medium

md5: ce3f8a07c6a7edad8e1997fb1e825980

Issue Description:

It is often useful to cycle over a sequence indefinitely. For example, just like you can write zip(repeatElement("foo", count: Int.max), myArray) and zip(1..., myArray), you could write {{zip([.grey,.white].cycle(), myArray)}}.

贡献者指南

技术栈
swift
领域
apideveloper experience
议题类型
feature
难度面向新贡献者的预计实现难度，1 表示很小改动，5 表示专家级工作。
2
预计时间有经验贡献者完成调查、实现、测试并准备 pull request 的粗略时间范围。
1-3 hours
活动状态议题当前的可参与程度：新鲜、活跃、陈旧、阻塞或等待维护者输入。
stale
清晰度议题是否清楚说明期望改动、验收标准和下一步。
clear
前置要求
Swift programming basicsSequence protocol familiarity
新手友好度1-100 的估计分数，表示该议题对首次贡献者的友好程度。
80
研究方向
Review the existing Sequence protocol in the Swift standard library (see file: stdlib/public/core/Sequence.swift). Examine how similar methods like repeatElement are implemented. Check if there are any prior proposals or discussions about this feature in the Swift Evolution process. Determine whether the cycle method should produce a lazy sequence or an eager collection. The implementation should respect Sequence semantics and potentially use LazySequenceProtocol.
[SR-6864] Add a "cycle" method to the standard library · swiftlang/swift#49413 | Good First Issue