Rescript frustration

this is a fact of life in rescript. you gotta be misinterpreting me, or i’m misinterpreting you. it’s the same with a switch statement today, each branch has to generate the same type output.

I’m looking here: rescript-core/src/Core__Option.res at main · rescript-lang/rescript-core · GitHub

there is no “map” function for None states, meaning you cant do something like value->Option.getOrElse(slowSyncOp). the value provided to getOr has to be computed before putting it into getOr. see what I mean?

same with andThen for result. these are not necessary, but provide some nice ergonomics.

i’m pulling code from a commercial project here so it’s a bit adjusted and lacks context (and also i’m pushing the boundaries of what i’m allowed to share):

  let result = switch str->split {
  | Ok(parts) => {
      parts->Array.reverse

      let rec processArgs = (acc) => {
        switch parts->Array.pop {
        | Some(name) =>
          switch args->Dict.get(name)->Option.map(handleArg(_, parts)) {
          | Some(Ok(value)) =>
            switch acc->Dict.get(name) {
            | Some(_) => Error(TooManyOccurrences(`Argument '${name}' must only be specified once`))
            | None => {
                acc->Dict.set(name, value)
                processArgs(acc)
              }
            }
          | Some(Error(e)) => Error(e)
          | None => Error(UnrecognizedArg(`Unrecognized argument: '${name}'`))
          }
        | None => Ok(acc)
        }
      }

      processArgs(Dict.make())
    }

this could be dedented trivially with early returns