--- title: Range as a functor | daily.dev description: This article explores the concept of ranges as functors in Haskell, F#, and C#, and how different elements of the range can be mapped. It discusses the default... canonical: https://daily.dev/posts/range-as-a-functor-yr65thj9n twitter:card: summary_large_image twitter:site: @dailydotdev og:type: website og:site_name: daily.dev og:title: Range as a functor | daily.dev og:description: This article explores the concept of ranges as functors in Haskell, F#, and C#, and how different elements of the range can be mapped. It discusses the default... og:url: https://daily.dev/posts/range-as-a-functor-yr65thj9n og:image: https://api.daily.dev/og/posts/YR65tHj9n.png og:image:alt: Range as a functor og:image:width: 1200 og:image:height: 630 og:locale: en --- > ## Documentation Index > Fetch the complete documentation index at: https://daily.dev/llms.txt > Use this file to discover all available pages before exploring further. # Range as a functor **[ploeh blog](https://daily.dev/sources/ploeh)** · 12 min read · 0 upvotes · 0 comments ## Summary This article explores the concept of ranges as functors in Haskell, F#, and C#, and how different elements of the range can be mapped. It discusses the default functor instances for pairs in Haskell, introduces the Data.Functor.Product module, and provides examples of how ranges can be projected and transformed. The article emphasizes that a functor is defined by how it follows the functor laws, even if the results may seem counter-intuitive in some cases. ## Full article daily.dev links to this article rather than hosting it. Read it at the original source: ## Similar posts on daily.dev - [Don’t just attend KubeCon \+ CloudNativeCon, Merge Forward your experience\!](https://daily.dev/posts/don-t-just-attend-kubecon-cloudnativecon-merge-forward-your-experience--l0rpp73x8) · CNCF · 1 upvotes · 0 comments - [Announcing H2 2026 KCDs](https://daily.dev/posts/announcing-h2-2026-kcds-m96goajm1) · CNCF · 1 upvotes · 0 comments - [Two months of Open Community Groups](https://daily.dev/posts/two-months-of-open-community-groups-asf52zhbs) · CNCF · 0 upvotes · 0 comments --- Tags: [#c#](https://daily.dev/tags/c#), [#fsharp](https://daily.dev/tags/fsharp), [#haskell](https://daily.dev/tags/haskell) [View this post on daily.dev](https://daily.dev/posts/range-as-a-functor-yr65thj9n) ```json {"@context":"https://schema.org","@graph":[{"@type":"Organization","@id":"https://daily.dev/#organization","name":"daily.dev","url":"https://daily.dev","logo":{"@type":"ImageObject","url":"https://daily.dev/apple-touch-icon.png","width":180,"height":180},"sameAs":["https://twitter.com/dailydotdev","https://github.com/dailydotdev","https://www.linkedin.com/company/daily-dev-ltd"]},{"@type":"WebSite","@id":"https://daily.dev/#website","url":"https://daily.dev","name":"daily.dev","publisher":{"@id":"https://daily.dev/#organization"},"potentialAction":{"@type":"SearchAction","target":{"@type":"EntryPoint","urlTemplate":"https://daily.dev/search?q={search_term_string}"},"query-input":"required name=search_term_string"}}]} {"@context":"https://schema.org","@type":"TechArticle","headline":"Range as a functor","url":"https://daily.dev/posts/range-as-a-functor-yr65thj9n","mainEntityOfPage":{"@type":"WebPage","@id":"https://daily.dev/posts/range-as-a-functor-yr65thj9n"},"datePublished":"2024-02-12T07:05:07.377Z","dateModified":"2026-05-14T02:15:11.119Z","description":"This article explores the concept of ranges as functors in Haskell, F#, and C#, and how different elements of the range can be mapped. 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