Result+Catch.swift

extension Result {
    public func `catch`(_ handler: () throws -> Success) -> Result<Success, Error> {
        flatMapError { _ in
            .init { try handler() }
        }
    }

    public func `catch`(_ handler: (Failure) throws -> Success) -> Result<Success, Error> {
        flatMapError { error in
            .init { try handler(error) }
        }
    }

    public func get(default defaultValue: @autoclosure () -> Success) -> Success {
        self.default(defaultValue)
    }

    public func `default`(_ handler: () -> Success) -> Success {
        self.default { _ in handler() }
    }

    public func `default`(_ handler: (Failure) -> Success) -> Success {
        switch self {
        case .success(let success):
            return success
        case .failure(let error):
            return handler(error)
        }
    }
}

Examples

Try all blocks in cascade until getting a success and extract the value, or throw if all blocks fail

let result: Int = try Result {
  try doThisFirst()
}.catch {
  try doThisIfFirstFails()
}.catch {
  try doThisIfSecondFails()
}.get()

Compare with regular do/catch

let result: Int 
do {
  result = try doThisFirst()
} catch {
  do {
    result = try doThisIfFirstFails()
  } catch {
    result = try doThisIfSecondFails()
  }
}

---

Try all blocks in cascade until getting a success and extract the value, or return the default value if all blocks fail

let result: Int = Result {
  try doThisFirst()
}.catch {
  try doThisIfFirstFails()
}.catch {
  try doThisIfSecondFails()
}.get(default: 42)

Compare with regular do/catch

let result: Int 
do {
  result = try doThisFirst()
} catch {
  do {
    result = try doThisIfFirstFails()
  } catch {
    do {
      result = try doThisIfSecondFails()
    } catch {
      result = 42
    }
  }
}

---

Try all blocks in cascade until getting a success and extract the value, or return the value from the non-throwing default block

let result: Int = Result {
  try doThisFirst()
}.catch {
  try doThisIfFirstFails()
}.catch {
  try doThisIfSecondFails()
}.default {
  doThisIfAllFail()
}

Compare with regular do/catch

let result: Int 
do {
  result = try doThisFirst()
} catch {
  do {
    result = try doThisIfFirstFails()
  } catch {
    do {
      result = try doThisIfSecondFails()
    } catch {
      result = doThisIfAllFail()
    }
  }
}

Thanks

Thanks @ABridoux for the help

👌