Type-checked non-empty strings

4 comments

• muglug 54 minutes ago
  Very cool that the language allows specification of a type in this way.

  I added a similar type — “non-empty-string” to a typechecker for PHP, and it’s been adopted widely in the PHP ecosystem. It turns out to be pretty handy, especially when there’s a full type system to support it.
• IshKebab 1 hour ago
  "Huh never heard of Bellroy... I wonder what they're using Haskell for..."

  Turns out it's some kind of bags and accessories brand!

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  • flexagoon 5 minutes ago
    I've had a Bellroy bag, they're not the most fashionable but super high quality and well thought-out. Just like Haskell code—maybe that's why they like it.
  • qbane 59 minutes ago
    I pondered for a while, it IS the company I used to know
• ivanjermakov 1 hour ago
  Language is not mentioned in a title, so my first thought was about TypeScript type wizardry. Turns out it's as simple as `Exclude<string, "">`.

  https://www.typescriptlang.org/docs/handbook/utility-types.h...

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  • antipurist 1 hour ago
    It's simple, and it doesn't work as `Exclude` only applies to union types. For type `string` it just returns the same type `string`.
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    • phpnode 34 minutes ago
      yup, it's not possible to do it safely with a simple unparameterised type: https://www.typescriptlang.org/play/?#code/C4TwDgpgBAcg9gOwK...
  • Cthulhu_ 37 minutes ago
    Speaking of TS, there's stuff in there for typing strings / string formats: https://www.typescriptlang.org/docs/handbook/2/template-lite...
  • ralferoo 1 hour ago
    It is very much mentioned in the article title and the first sentence. It's just HN that's truncated the title.
  • nvme0n1p1 31 minutes ago
    Daily reminder that TypeScript's type checker is not sound.

    https://www.typescriptlang.org/play/?#code/C4TwDgpgBAcg9gOwK...
• swordlucky666 1 hour ago
  [dead]