FsToolkit.ErrorHandling
  • README
  • FsToolkit.ErrorHandling
    • Result
      • apply
      • bind
      • check
      • Computation Expression
      • either Functions
      • fold
      • ignore
      • map
      • map2
      • map3
      • mapError
      • Operators
      • orElse Functions
      • Other Functions
      • require Functions
      • tee Functions
      • tryCreate
      • zip
      • zipError
      • Lists
        • traverseResultM
        • sequenceResultM
        • traverseResultA
        • sequenceResultA
      • Sequences
        • traverseResultM
        • sequenceResultM
        • traverseResultA
        • sequenceResultA
      • Transforms
        • ofChoice
    • Option
      • bind
      • bindNull
      • Computation Expression
      • either
      • map
      • map2
      • map3
      • sequenceAsync
      • sequenceResult
      • sequenceTask
      • sequenceTaskResult
      • tee Functions
      • traverseAsync
      • traverseResult
      • traverseTask
      • traverseTaskResult
      • zip
      • Lists
        • traverseOptionM
        • sequenceOptionM
        • traverseVOptionM
        • sequenceVOptionM
      • Sequences
        • traverseOptionM
        • sequenceOptionM
        • traverseVOptionM
        • sequenceVOptionM
      • Transforms
        • ofNull
        • ofPair
        • ofResult
        • ofValueOption
        • toValueOption
    • ResultOption
      • apply
      • bind
      • Computation Expression
      • ignore
      • map
      • map2
      • map3
      • mapError
      • Operators
      • zip
      • zipError
      • Transforms
        • ofChoice
        • ofOption
        • ofResult
    • AsyncResult
      • apply
      • bind
      • check
      • Computation Expression
      • error
      • foldResult
      • ignore
      • map
      • map2
      • map3
      • mapError
      • Operators
      • Other Functions
      • zip
      • zipError
      • List
        • traverseAsyncResultM
        • sequenceAsyncResultM
        • traverseAsyncResultA
        • sequenceAsyncResultA
      • Sequences
        • traverseAsyncResultM
        • sequenceAsyncResultM
        • traverseAsyncResultA
        • sequenceAsyncResultA
      • Transforms
        • ofAsync
        • ofResult
        • ofTask
        • ofTaskAction
    • AsyncOption
      • apply
      • bind
      • Computation Expression
      • either
      • map
      • orElse Functions
      • Other Functions
    • AsyncResultOption
      • apply
      • bind
      • Computation Expression
      • error
      • ignore
      • map
      • map2
      • map3
      • Operators
      • Transforms
        • ofAsyncOption
        • ofAsyncResult
        • ofOption
        • ofResult
    • Task
      • apply
      • bind
      • bindV
      • catch
      • Computation Expression
      • ignore
      • map
      • mapV
      • map2
      • map3
      • zip
      • Transforms
        • ofUnit
    • TaskOption
      • apply
      • bind
      • Computation Expression
      • either
      • map
      • Other Functions
      • zip
    • TaskValueOption
      • apply
      • bind
      • Computation Expression
      • either
      • map
      • Other Functions
      • zip
    • TaskResult
      • apply
      • bind
      • check
      • catch
      • Computation Expression
      • ignore
      • map
      • map2
      • map3
      • mapError
      • Operators
      • Other Functions
      • error
      • zip
      • zipError
      • Lists
        • traverseTaskResultM
        • sequenceTaskResultM
        • traverseTaskResultA
        • sequenceTaskResultA
      • Transforms
        • ofAsync
        • ofResult
        • ofTask
    • TaskResultOption
      • apply
      • bind
      • Computation Expression
      • error
      • ignore
      • map
      • map2
      • map3
      • Operators
    • Validation
      • apply
      • Computation Expression
      • error
      • map
      • map2
      • map3
      • mapError
      • mapErrors
      • Operators
      • zip
      • Transforms
        • ofChoice
        • ofResult
    • AsyncValidation
      • apply
      • Computation Expression
      • error
      • map
      • map2
      • map3
      • mapError
      • mapErrors
      • Operators
      • zip
      • Transforms
        • ofChoice
        • ofResult
    • TaskValidation
      • apply
      • Computation Expression
      • error
      • map
      • map2
      • map3
      • mapError
      • mapErrors
      • Operators
      • zip
      • Transforms
        • ofChoice
        • ofResult
  • FsToolkit.ErrorHandling.AsyncSeq
    • AsyncSeq
      • Computation Expression
  • FsToolkit.ErrorHandling.IcedTasks
    • CancellableTaskOption
      • apply
      • bind
      • Computation Expression
      • either
      • map
      • Other Functions
      • zip
    • CancellableTaskResult
      • apply
      • bind
      • Computation Expression
      • getCancellationToken
      • map
      • Operators
      • Other Functions
      • zip
      • parallelZip
    • CancellableTaskValidation
      • apply
      • bind
      • Computation Expression
      • error
      • getCancellationToken
      • map
      • map2
      • map3
      • mapError
      • mapErrors
      • Operators
      • zip
      • parallelZip
      • Transforms
        • ofChoice
        • ofResult
  • FsToolkit.ErrorHandling.JobResult
    • Job
      • apply
      • map2
      • map3
      • singleton
      • zip
    • JobOption
      • apply
      • bind
      • ce
      • either
      • map
    • JobResult
      • apply
      • bind
      • catch
      • Computation Expression
      • error
      • fromTask
      • fromUnitTask
      • ignore
      • map
      • map2
      • map3
      • mapError
      • Operators
      • Other Functions
      • zip
      • zipError
      • Lists
        • traverseJobResultM
        • sequenceJobResultM
        • traverseJobResultA
        • sequenceJobResultA
      • Transforms
        • ofAsync
        • ofJob
        • ofResult
        • fromTask
        • fromUnitTask
    • JobResultOption
      • apply
      • bind
      • Computation Expression
      • ignore
      • map
      • map2
      • map3
  • General Docs
    • Bind Mappings
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  • Examples
  • Example 1
  • Example 2
  1. FsToolkit.ErrorHandling
  2. ResultOption

Operators

Namespace: FsToolkit.ErrorHandling.Operator.ResultOption

FsToolkit.ErrorHandling provides the standard infix operators for the map (<!>), apply (<*>), and bind (>>=) functions of the Result<Option<_>,_> type.

In addition to these, it also offers an another infix operator <*^> for usage with normal Result values (without an inner Option). It has the following function signature:

Result<('a -> 'b) option, 'c> -> Result<'a, 'c> 
  -> Result<'b option, 'c>

Examples

Example 1

Assume that we have the following function:

// int -> int -> int -> int
let add a b c = a + b + c

Then using the infix operators, we can do the following:

// Ok (Some 42)
let opResult : Result<int option, string> =
  add
  <!> (Ok (Some 30)) 
  <*> (Ok (Some 10)) 
  <*> (Ok (Some 2)) 

If we have values that are not Option wrapped, we can use the <*^> operator:

let opResult : Result<int option, string> =
  add
  <!> (Ok (Some 30)) 
  <*^> (Ok 10) 
  <*> (Ok (Some 2))

Example 2

let toCreatePostRequest (dto : CreatePostRequestDto) = 

  // Result<Location option, string>
  let locationR = 
    location
    <!> Option.traverseResult Latitude.TryCreate dto.Latitude
    <*> Option.traverseResult Longitude.TryCreate dto.Longitude

  // Result<Tweet, string>
  let tweetR = Tweet.TryCreate dto.Tweet

  // Result<CreatePostRequest, string>
  Result.map2 createPostRequest tweetR locationR
PreviousmapErrorNextzip

Last updated 1 year ago

The can be written using the infix operators as below:

ResultOption.map2 example