Computation Expression

CancellableTaskValidation Computation Expression

Namespace: FsToolkit.ErrorHandling

The CancellableTaskValidation type is defined as:

type CancellableTaskValidation<'a,'err> = CancellableTask<Result<'a, 'err list>>

This CE can take advantage of the and! operator to join multiple error results into a list.

Examples

See here for other validation-like examples

// Result<string, string> -> CancellableTask<Result<string, string>>
let downloadCancellableTask stuff = cancellableTask {
    return stuff
}

// CancellableTaskValidation<string, string>
let result = cancellableTaskValidation {
  let! x = downloadCancellableTask (Ok "I")
  and! y = downloadCancellableTask (Ok "am")
  and! z = downloadCancellableTask (Ok "cancellableTask!")
  return sprintf "%s %s %s" x y z
}
// cancellableTask { return Ok "I am cancellableTask!" }

// CancellableTaskValidation<string, string>
let result = cancellableTaskValidation {
  let! x = downloadCancellableTask (Error "Am")
  and! y = downloadCancellableTask (Error "I")
  and! z = downloadCancellableTask (Error "cancellableTask?")
  return sprintf "%s %s %s" x y z
}

// cancellableTask { return Error [ "Am"; "I"; "cancellableTask?" ] }