Add the ability to decode more than 9 fields. about stdlib HOT 4 CLOSED

I'm probably missing something, but I bumped into (what I perceive to be) a hard limit of 9 fields using dynamic.decodeN with gleam/pgo.

Hello! If you need to decode more than 9 things at a time you have a couple options:

• You can use a combination of decoders and result.try: notice how a decoder is nothing more than a function returning a Result, so you can combine them with the result module's functions:

  pub fn decode_n(dynamic, decoder_1, ..., decoder_n) {
    use field_1 <- result.try(decoder_1(dynamic))
    ...
    use field_n <- result.try(decoder_n(dynamic))
    Ok(...)
  }

  This is probably going to be the most concise way to do it; the trade-off is that you're going to only get the first decoding error you meet since result.try is short circuiting
• You could have a look at how decodeN functions are implemented and copy that for any N, the code is probably not going to look great but with this approach you can accumulate all the decoding errors you run into. If that's not a dealbreaker for you I'd go for the first approach

  // It looks roughly something like this...
  pub fn decode_n(dynamic, decoder_1, ..., decoder_n) {
    case decoder_1(dynamic), ..., decoder_n(dynamic) {
      Ok(res_1), ..., Ok(res_n) -> Ok(...)
      res_1, ..., res_n ->
        [all_errors(res_1), ..., all_errors(res_n)]
        |> list.concat
        |> Error
    }
  }

from stdlib.

Thank you all for taking the time help.

from stdlib.

Why is this necessary over defining your own decoder as a function which would allow you to support an arbitrary number of fields?

from stdlib.

Or you could call one of the decode functions multiple times!

Thanks all

from stdlib.