TypeScript Is Surprisingly OK for Compilers

Re:TypeScript Is Surprisingly OK for Compilers by kaba0 on Friday August 18, 2023 @04:36AM (#37172830)

It can and you in fact either have to mark that you return that error when you use try, or you have to provide a default value in a catch block:

``` fn potentiallyErrorReturningFunc() !u64 { ... }

const foo = potentiallyErrorReturningFunc() catch { 0 }; ```

One notable difference to most other languages is it being a value only, basically a product type of return value XOR error. These error values get serialized into a number by the compiler that is unique, and on the type system level you deal with sets of these error values. Quite clever in case of a low-level system, in my opinion.

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Re:TypeScript Is Surprisingly OK for Compilers by flohofwoe on Friday August 18, 2023 @06:14AM (#37173602)

> const foo = potentiallyErrorReturningFunc() catch { 0 };

Nitpick, but AFAIK this won't work and needs to be rewritten either to:

    const foo = potentiallyErrorReturningFunc() catch 0;

...or to:

    const foo = potentiallyErrorReturningFunc() catch blk: { break :blk 0; }

(I wish there would be a more convenient way to return a value from a scope block, not necessarily with a "dangling expression" like Rust, but maybe at least getting rid of the label somehow)

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