Type-checked non-empty strings

Discussion (10 Comments)Read Original on HackerNews

muglug•about 1 hour 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•about 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!

flexagoon•3 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•about 1 hour ago

I pondered for a while, it IS the company I used to know

ivanjermakov•about 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...

antipurist•about 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`.

phpnode•31 minutes ago

yup, it's not possible to do it safely with a simple unparameterised type: https://www.typescriptlang.org/play/?#code/C4TwDgpgBAcg9gOwK...

Cthulhu_•35 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•about 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•29 minutes ago

Daily reminder that TypeScript's type checker is not sound.

https://www.typescriptlang.org/play/?#code/C4TwDgpgBAcg9gOwK...

Type-checked non-empty strings

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Discussion (10 Comments)Read Original on HackerNews