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Unfortunately, even with fp-ts, typescript does not yet have the means to enable ergonomic handling of errors without exceptions. I hope they improve this in th

Unfortunately, even with fp-ts, typescript does not yet have the means to enable ergonomic handling of errors without exceptions. I hope they improve this in the future though.

epolanski 4y ago
As a daily fp-ts user I'm not sure I agree, you handle them with the appropriate data type: Either. Exceptions are a path like any other, there's nothing really magical about those, you catch the functions that could throw and handle the fact they have thrown the error, which error, why? There's two helpers for that in fp-ts [1][2] plus the obvious lazy and asynchronous counter parts in the TaskEither and ReaderTaskEither modules. [1]https://gcanti.github.io/fp-ts/modules/Either.ts.html#trycatch https://gcanti.github.io/fp-ts/modules/Either.ts.html#trycat... [2]https://gcanti.github.io/fp-ts/modules/Either.ts.html#trycatchk https://gcanti.github.io/fp-ts/modules/Either.ts.html#trycat...
- valenterry 4y ago
  I think it's a matter of perspective. I tried to user Either, but without proper pattern matching and syntactic sugar for monadic operations, I didn't quite like it. That being said, I think the authors did a great job to make it as good as possible given the limitations.
  - epolanski 4y ago
    Could you show the limitations you're speaking of? I know fp-ts very well and it does not have those limitations you're speaking of. Either admits all of the functor, bifunctor, monad, apply, applicative and traversable instances in fp-ts (so do all the other bifunctors) so there's no shortage of combinators.
    - valenterry 4y ago
      Essentially, I want do write things in the style of (pseudocode) do { result1 <- either1 result2 <- either2 result3 <- fooReturningEither(result1, resul2) } yield result1 + result3 and so on. This gets very noisy without syntactic sugar.
    - epolanski 4y ago
      @valenterry (I can't reply further), you can do that: https://codesandbox.io/s/wispy-shadow-7789p6?file=/src/index.ts https://codesandbox.io/s/wispy-shadow-7789p6?file=/src/index... In whatever ways you want to complicate it (with exceptions, asynchronous operations, with or without Do syntax) you can easily do that in fp-ts.
      - valenterry 4y ago
        You can click on the timestamp of the post to reply next time ;)
        epolanski 4y ago
        Today I learned, thank you.
      - valenterry 4y ago
        (edited) That's actually not too bad!
      - valenterry 4y ago
        If you are still here: any resources on how to build those other things that you mentioned myself? For example, if I would like to combine either and reader into a single monad, how would that look like? Now I'm kinda thrilled!

Unfortunately, even with fp-ts, typescript does not yet have the means to enable ergonomic handling of errors without exceptions. I hope they improve this in the future though.

epolanski 4y ago

As a daily fp-ts user I'm not sure I agree, you handle them with the appropriate data type: Either. Exceptions are a path like any other, there's nothing really magical about those, you catch the functions that could throw and handle the fact they have thrown the error, which error, why? There's two helpers for that in fp-ts [1][2] plus the obvious lazy and asynchronous counter parts in the TaskEither and ReaderTaskEither modules. [1]https://gcanti.github.io/fp-ts/modules/Either.ts.html#trycatch https://gcanti.github.io/fp-ts/modules/Either.ts.html#trycat... [2]https://gcanti.github.io/fp-ts/modules/Either.ts.html#trycatchk https://gcanti.github.io/fp-ts/modules/Either.ts.html#trycat...

valenterry 4y ago
I think it's a matter of perspective. I tried to user Either, but without proper pattern matching and syntactic sugar for monadic operations, I didn't quite like it. That being said, I think the authors did a great job to make it as good as possible given the limitations.
- epolanski 4y ago
  Could you show the limitations you're speaking of? I know fp-ts very well and it does not have those limitations you're speaking of. Either admits all of the functor, bifunctor, monad, apply, applicative and traversable instances in fp-ts (so do all the other bifunctors) so there's no shortage of combinators.
  - valenterry 4y ago
    Essentially, I want do write things in the style of (pseudocode) do { result1 <- either1 result2 <- either2 result3 <- fooReturningEither(result1, resul2) } yield result1 + result3 and so on. This gets very noisy without syntactic sugar.
  - epolanski 4y ago
    @valenterry (I can't reply further), you can do that: https://codesandbox.io/s/wispy-shadow-7789p6?file=/src/index.ts https://codesandbox.io/s/wispy-shadow-7789p6?file=/src/index... In whatever ways you want to complicate it (with exceptions, asynchronous operations, with or without Do syntax) you can easily do that in fp-ts.
    - valenterry 4y ago
      You can click on the timestamp of the post to reply next time ;)
      - epolanski 4y ago
        Today I learned, thank you.
    - valenterry 4y ago
      (edited) That's actually not too bad!
    - valenterry 4y ago
      If you are still here: any resources on how to build those other things that you mentioned myself? For example, if I would like to combine either and reader into a single monad, how would that look like? Now I'm kinda thrilled!