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 3 hours 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!
flexagoon 2 hours 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 3 hours ago [-]
I pondered for a while, it IS the company I used to know
ambicapter 45 minutes ago [-]
I once saw a job ad for a company selling a horoscope app that required Haskell. An unusual conjunction for sure.
saithound 3 minutes ago [-]
Astrology and Haskell are quite similar in that both are much much easier to do if you have a math degree.
gib444 17 minutes ago [-]
Using Haskell for a horoscope app is like hiring a mathematician to read tea leaves
ivanjermakov 3 hours 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, "">`.
This example is not only wrong for what you intend to demonstrate but even if it wasn't, it's not problematic. In typescript the proper way to do this is using branded types and exporting only the safe constructor, making anyone who wants to violate the invariant go out of their way, which is no different from the situation in any number of programming languages or scenarios.
declare const brand: unique symbol;
type NonEmptyString = string & { readonly [brand]: 'NonEmptyString' };
// the ONLY non-cast way to produce one
export function nonEmptyString(s: string): NonEmptyString | undefined {
return s.length > 0 ? (s as NonEmptyString) : undefined;
}
export type { NonEmptyString };
swordlucky666 3 hours ago [-]
[dead]
Rendered at 16:46:57 GMT+0000 (Coordinated Universal Time) with Vercel.
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.
Turns out it's some kind of bags and accessories brand!
https://www.typescriptlang.org/docs/handbook/utility-types.h...
Edit: nevermind, LLM fooled me.
https://www.typescriptlang.org/play/?#code/C4TwDgpgBAcg9gOwK...