Impossible to create an instance of the Costrong class
還沒有人認領這個 Issue。
評估
- 難度
- 5/5
- 預估耗時
- 一週以上
- 新手友好度
- 25/100
- Issue 類型
- 功能
- 描述清晰度
- 基本清楚
- 活躍度
- 停滯
- 領域
- backend
研究方向
Start by reading the Costrong class and its unfirst method; the issue gives no file or test paths, so locate them in the repository. Compare the strict definition with the proposed Lazy constraint and consider the naming or library scope raised in the issue. Done means establishing whether the proposed approach is viable and agreeing on the API direction.
由索引模型根據 Issue 內容生成。
描述
The reason that Function and other types cannot be an instance of Costrong is that PureScript is a strict evaluation.
unfirst :: forall a b c. p (Tuple a c) (Tuple b c) -> p a b
That is, when we want to loop over c, it is impossible to set the initial value of c
How to modify it may be debatable, but I found the following solution
unfirstLazy :: forall a b c. Lazy c => p (Tuple a c) (Tuple b c) -> p a b
unfirstLazy f a = fst $ f $ Tuple a $ go
where
go = snd $ f $ Tuple a $ defer \_ -> go
Also, since this is not "Co" Strong, it might be better to name the class differently, for example CostrongLazy, or create a new library.
Thanks to natefaubion for sharing this issue on PureScript discord server.
- 主要語言
- PureScript
- 星號
- 34
- 分支
- 13
- 平均合併
- 3 天 10 分鐘
- 30 天內合併 PR
- 1
環境準備
- 沒有 Dockerfile 或 Docker Compose 檔案
- 有 Pull Request 範本
- 沒有貢獻指南
從這裡開始
- 先讀完整個 Issue，再讀專案的貢獻指南。
- 在 Issue 下留言說明你要接手 —— 這能避免兩個人做同樣的事。
- Fork 儲存庫，在一個分支上完成修改。
- 送出 Pull Request，並在描述裡引用這個 Issue 編號。
purescript/purescript-profunctor 的其他 Issue
-
難度 4/5 3-5 天 新手友好度 28/100
purescript/purescript-profunctor#49 · 1 則留言 ·
-
status: needs more info
難度 5/5 一週以上 新手友好度 25/100
purescript/purescript-profunctor#32 · 1 則留言 ·
-
type: enhancement
難度 5/5 一週以上 新手友好度 20/100
查看 purescript/purescript-profunctor 的全部 Issue
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