Add Divisible and Decideable (contravariant Applicative and co.)

描述

貢獻者指南

技術棧

scala

領域

backend

議題類型

feature

難度面向新貢獻者的預計實作難度，1 表示很小改動，5 表示專家級工作。

4

預計時間有經驗貢獻者完成調查、實作、測試並準備 pull request 的粗略時間範圍。

over 1 week

活動狀態議題目前的可參與程度：新鮮、活躍、陳舊、阻塞或等待維護者輸入。

stale

清晰度議題是否清楚說明預期改動、驗收標準和下一步。

needs investigation

前置要求

cats library basicstype classescontravariant functorsscala syntax

新手友善度1-100 的估計分數，表示該議題對首次貢獻者的友善程度。

15

研究方向

Research the Divisible and Decidable type classes from the Haskell contravariant package (https://hackage.haskell.org/package/contravariant 1.4/docs/Data Functor Contravariant Divisible.html). Study the existing Contravariant type class in cats (e.g., cats core/src/main/scala/cats/Contravariant.scala) to understand the pattern. Define new Divisible and Decidable traits and provide instances for common types. Since the issue has been open long, consider posting a design proposal before implementation to ensure maintainer alignment.